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Infineon C161RI User`s Manual

1. Reload Value Prescaler for fepu in WDTREL 2 WDTIN 0 128 WDTIN 1 20 MHz 16 MHz 12 MHz 20 MHz 16 MHz 12 MHz FF 25 6 us 32 0 us 42 67 us 1 64 ms 2 05 ms 2 73 ms 7Fy 3 3 ms 4 13ms 5 5ms 211 ms 264 ms 352 ms 00 6 55 ms 8 19 ms 10 92 ms 419 ms 524 ms 699 ms Note For safety reasons the user is advised to rewrite WDTCON each time before the watchdog timer is serviced Semiconductor Group 13 3 1998 05 01 SIEMENS The Watchdog Timer WDT C161RI 13 2 Reset Source Indication The reset indication flags in register WDTCON provide information on the source for the last reset As the C161RI starts executing from location 00 0000 after any possible reset event the initialization software may check these flags in order to determine if the recent reset event was triggered by an external hardware signal via RSTIN by software itself or by an overflow of the watchdog timer The initialization and also the further operation of the microcontroller system can thus be adapted to the respective circumstances e g a special routine may verify the software integrity after a watchdog timer reset The reset indication flags are not mutually exclusive i e more than one flag may be set after reset depending on its source The table below summarizes the possible combinations Reset Indication Flag Combinations Reset Indication Flags Reset Source LHWR SHWR SWR WDTR L
2. CS Signal Generation During external accesses the EBC can generate a programmable number of CS lines on Port 6 which allow to directly select external peripherals or memory banks without requiring an external decoder The number of CS lines is selected during reset and coded in bit field CSSEL in register RPOH see table below CSSEL Chip Select Lines Note 1 1 Five CS4 CSO Default without pull downs 10 None Port 6 pins free for IO 01 Two CS1 CSO 00 Three CS2 CS0 The CSx outputs are associated with the BUSCONXx registers and are driven active low for any access within the address area defined for the respective BUSCON register For any access outside this defined address area the respective CSx signal will go inactive high At the beginning of each external bus cycle the corresponding valid CS signal is determined and activated All other CS lines are deactivated driven high at the same time Note The CSx signals will not be updated for an access to any internal address area i e when no external bus cycle is started even if this area is covered by the respective ADDRSELx register An access to an on chip X Peripheral deactivates all external CS signals Upon accesses to address windows without a selected CS line all selected CS lines are deactivated Semiconductor Group 9 8 1998 06 01 SIEMENS The External Bus Interface C161RI The chip select signals allow to be operated
3. TXDO P3 10 Receive Buffer Reg Transmit Buffer Reg SORBUF SOTBUF Internal Bus ucet Figure 11 2 Asynchronous Mode of Serial Channel ASCO Semiconductor Group 11 4 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Asynchronous Data Frames 8 bit data frames either consist of 8 data bits D7 DO SOM 0015 or of 7 data bits D6 DO plus an automatically generated parity bit SOM 011 Parity may be odd or even depending on bit SOODD in register SOCON An even parity bit will be set if the modulo 2 sum of the 7 data bits is 1 An odd parity bit will be cleared in this case Parity checking is enabled via bit SOPEN always OFF in 8 bit data mode The parity error flag SOPE will be set along with the error interrupt request flag if a wrong parity bit is received The parity bit itself will be stored in bit SORBUF 7 Do D1 D2 D3 D4 D5 D7 LSB Parity Asynchronous 8 bit Data Frames Figure 11 3 9 bit data frames either consist of 9 data bits D8 DO SOM 1005 of 8 data bits D7 DO plus an automatically generated parity bit SOM 111 or of 8 data bits D7 DO plus wake up bit SOM 1015 Parity may be odd or even depending on bit SOODD in register SOCON An even parity bit will be set if the modulo 2 sum of the 8 data bits is 1 An odd parity bit will be cleared in this case Parity checking is enabled via bit SOPEN
4. Figure 13 2 Watchdog Timer Block Diagram Semiconductor Group 13 1 1998 05 01 SIEMENS The Watchdog Timer WDT C161RI 13 1 Operation of the Watchdog Timer The current count value of the Watchdog Timer is contained in the Watchdog Timer Register WDT which is a non bitaddressable read only register The operation of the Watchdog Timer is controlled by its bitaddressable Watchdog Timer Control Register WDTCON This register specifies the reload value for the high byte of the timer selects the input clock prescaling factor and provides flags that indicate the source of a reset WDTCON FFAE D7 SFR Reset Value 00XX 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 r r r r rw rw Bit Function WDTIN Watchdog Timer Input Frequency Selection 0 Input frequency is fopy 2 1 Input frequency is fopy 128 WDTR Watchdog Timer Reset Indication Flag Cleared by a hardware reset or by the SRVWDT instruction SWR Software Reset Indication Flag SHWR Short Hardware Reset Indication Flag LHWR Long Hardware Reset Indication Flag WDTREL Watchdog Timer Reload Value for the high byte of WDT Note The reset value depends on the reset source see description below The execution of EINIT clears the reset indication flags After any software reset external hardware reset see note or watchdog timer reset the watchdog timer is enabled and starts counting up from 0000 with the frequency fcp 2 The inpu
5. Specify the size of the physical system stack area within the internal RAM bitfield STKSZ in register SYSCON Define two pointers which specify the upper and lower boundary of the external stack These values are then tested in the stack underflow and overflow trap routines when moving data Set the stack overflow pointer STKOV to the limit of the defined internal stack area plus six words for the reserved space to store two interrupt entries The internal stack will now fill until the overflow pointer is reached After entry into the overflow trap procedure the top of the stack will be copied to the external memory The internal pointers will then be modified to reflect the newly allocated space After exiting from the trap procedure the internal stack will wrap around to the top of the internal stack and continue to grow until the new value of the stack overflow pointer is reached When the underflow pointer is reached while the stack is emptied the bottom of stack is reloaded from the external memory and the internal pointers are adjusted accordingly Linear Stack The C161RI also offers a linear stack option STKSZ 111 where the system stack may use the complete internal RAM area This provides a large system stack without requiring procedures to handle data transfers for a circular stack However this method also leaves less RAM space for variables or code The RAM area that may effectively be consumed by the s
6. The result of a conversion is stored in the result register ADDAT ADDAT FEAQ 50 SFR Reset Value 0000 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 7 rw Bit Function ADRES A D Conversion Result The 8 bit result is stored right or left adjusted according to bit ADRP ADRP 0 Result in ADRES 9 2 left adjusted ADRES 1 0 00 ADRP 1 Result in ADRES 7 0 right adjusted ADRES 9 8 00 A conversion is started by setting bit ADST 1 The busy flag ADBSY will be set and the converter then selects and samples the input channel which is specified by the channel selection field ADCH in register ADCON The sampled level will then be held internally during the conversion When the conversion of this channel is complete the 8 bit result is transferred into the result register ADDAT and the interrupt request flag ADCIR is set The conversion result is placed into bitfield ADRES of register ADDAT left or right adjusted depending on bit ADRP in register ADCON If bit ADST is reset via software while a conversion is in progress the A D converter will stop after the current conversion Setting bit ADST while a conversion is running will abort this conversion and start a new conversion with the parameters specified in ADCON Note Abortion and restart see above are triggered by bit ADST changing from 0 to 1 i e ADST must be 0 before being set While a conversion is in progr
7. A short hardware reset is extended to the duration of the internal reset sequence Semiconductor Group 18 3 1998 06 01 SIEMENS System Reset C161RI The C161RI s Pins after Reset After the reset sequence the different groups of pins of the C161RI are activated in different ways depending on their function Bus and control signals are activated immediately after the reset sequence according to the configuration latched from PORTO so either external accesses can takes place or the external control signals are inactive The general purpose IO pins remain in input mode high impedance until reprogrammed via software see figure below The RSTOUT pin remains active low until the end of the initialization routine see description Internal Reset Condition 39 Initialization 6 3 RSTIN Internal Reset Condition Initialization When the internal reset condition is extended by RSTIN the activation of the output signals is delayed until the end of the internal reset condition 1 Current bus cycle is completed or aborted 2 Switches asynchronously with RSTIN synchronously upon software or watchdog reset 3 The reset condition ends here The C161RI starts program execution 4 Activation of the IO pins is controlled by software 5 Execution of the EINIT instruction 6 7 8 The shaded area designates the internal rese
8. Bit Function GLVL Group Level Defines the internal order for simultaneous requests of the same priority 3 Highest group priority 0 Lowest group priority ILVL Interrupt Priority Level Defines the priority level for the arbitration of requests F4 Highest priority level Op Lowest priority level xxlE Interrupt Enable Control Bit individually enables disables a specific source 0 Interrupt request is disabled 1 Interrupt Request is enabled xxIR Interrupt Request Flag 0 No request pending 1 This source has raised an interrupt request The Interrupt Request Flag is set by hardware whenever a service request from the respective source occurs It is cleared automatically upon entry into the interrupt service routine or upon a PEC service In the case of PEC service the Interrupt Request flag remains set if the COUNT field in register PECCx of the selected PEC channel decrements to zero This allows a normal CPU interrupt to respond to a completed PEC block transfer Note Modifying the Interrupt Request flag via software causes the same effects as if it had been set or cleared by hardware Interrupt Priority Level and Group Level The four bits of bit field ILVL specify the priority level of a service request for the arbitration of simultaneous requests The priority increases with the numerical value of ILVL so 0000 is the lowest and 1111 is the highest priority level When mor
9. P D mode f RTC RTC Oscillator Frequency Control Clock Drivers Figure 6 1 CPU Clock Generation Stages Semiconductor Group 6 1 1998 05 01 SIEMENS Clock Generation C161RI 6 1 Oscillator The main oscillator of the C161RI is a power optimized Pierce oscillator providing an inverter and a feedback element Pins XTAL1 and XTAL2 connect the inverter to the external crystal The standard external oscillator circuitry see figure below comprises the crystal two low end capacitors and series resistor Rx2 to limit the current through the crystal The additional LC combination is only required for 3rd overtone crystals to suppress oscillation in the fundamental mode A test resistor Ro may be temporarily inserted to measure the oscillation allowance of the oscillator circuitry XTAL1 XTAL2 l Ra Rx2 Figure 6 2 External Oscillator Circuitry The on chip oscillator is optimized for an input frequency range of 1 to 16 MHz An external clock signal e g from an external oscillator or from a master device may be fed to the input XTAL1 The Pierce oscillator then is not required to support the oscillation itself but is rather driven by the input signal In this case the input frequency range may be 0 to 50 MHz please note that the maximum applicable input frequency is limited by the device s maximum CPU frequency For input frequencies above 25 30 MHz the oscillator s output should be terminated as shown
10. Semiconductor Group 7 3 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Port Functions In order to provide a maximum of flexibility for different applications and their specific IO requirements port lines have programmable alternate input or output functions associated with them Alternate Port Functions Port Alternate Function s PORTO Address and data lines when accessing external resources e g memory PORT1 Address lines when accessing external resources e g memory Port 2 Fast external interrupt inputs Port 3 Input output functions of timers serial interfaces Optional bus control signal BHE WRH and system clock output CLKOUT Port 4 Additional selected segment address bits Axx A16 in systems where more than 64 KBytes of memory are to be accessed directly Port 5 Analog input channels to the A D converter Timer control signal inputs Port 6 Chip select output signals and EFC interface lines If an alternate output function of a pin is to be used the direction of this pin must be programmed for output DPx y 1 except for some signals that are used directly after reset and are configured automatically Otherwise the pin remains in the high impedance state and is not effected by the alternate output function The respective port latch should hold a 1 because its output is combined with the alternate output data If an alternate input function of a pin is used the direction
11. 16 bit XSSCBM 1 SSCHB SSC Heading Control Bit 0 Transmit Receive LSB First 1 Transmit Receive MSB First SSCPH SSC Clock Phase Control Bit 0 Shift transmit data on the leading clock edge latch on trailing edge 1 Latch receive data on leading clock edge shift on trailing edge SSCPO SSC Clock Polarity Control Bit 0 Idle clock line is low leading clock edge is low to high transition 1 Idle clock line is high leading clock edge is high to low transition SSCTEN SSC Transmit Error Enable Bit 0 Ignore transmit errors 1 Check transmit errors SSCREN SSC Receive Error Enable Bit 0 Ignore receive errors d Check receive errors SSCPEN SSC Phase Error Enable Bit 0 Ignore phase errors 1 Check phase errors SSCBEN SSC Baudrate Error Enable Bit 0 Ignore baudrate errors Tz Check baudrate errors SSCAREN SSC Automatic Reset Enable Bit 0 No additional action upon a baudrate error 1 The SSC is automatically reset upon a baudrate error SSCMS SSC Master Select Bit 0 Slave Mode Operate on shift clock received via SCLK 1 Master Mode Generate shift clock and output it via SCLK SSCEN SSC Enable Bit 0 Transmission and reception disabled Access to control bits Semiconductor Group 12 3 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI SSCCON FFB2 D9 SFR Reset Value 0000 15 14 13 12 11 40 9 8 7 6 5 4 3 2 1 0 SSC SSC SSC SSC SSC SSC SSC rw rw rw r
12. CSRENx Read Chip Select Enable 0 The CS signal is independent of the read command RD 1 The CS signal is generated for the duration of the read command CSWENx Write Chip Select Enable 0 The CS signal is independent of the write command WR WRL WRH 1 The CS signal is generated for the duration of the write command Semiconductor Group 9 20 1998 06 01 SIEMENS The External Bus Interface C161RI ADDRSEL1 FE18 0C SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ADDRSEL2 FE1A OD SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ADDRSEL3 FE1C OE SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ADDRSEL4 FE1E OF SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 UJ it Function RGSZ Range Size Selection Defines the size of the address area controlled by the respective BUSCONx ADDRSELx register pair See table below RGSAD Range Start Address Defines the upper bits of the start address A23 of the respective address area See table below Note There is no register ADDRSELO as register BUSCONO controls all external accesses outside the four address windows of BUSCONA BUSCON1 within the complete address space Semiconductor Group 9 21 1998 06 01 SIEMENS The External Bus Interface C161RI Definition of Address Areas The four register pairs BUSCON4 ADDRSEL4 BUSCON1 ADDRSEL1 allow to define 4 separate
13. Note Bit T5SC only controls whether a capture is performed or not If T5SC 0 the selected trigger event can still be used to clear timer T5 or to generate an interrupt request This interrupt is controlled by the CAPREL interrupt control register CRIC Up Down Auxiliary Timer T5 TSIR ele Edge Select Interrupt CRIR Request CAPREL Register MCB02044 Figure 10 19 GPT2 Register CAPREL in Capture Mode Semiconductor Group 10 26 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT2 Capture Reload Register CAPREL in Reload Mode This 16 bit register can be used as a reload register for the core timer T6 This mode is selected by setting bit T6SR 1 in register TECON The event causing a reload in this mode is an overflow or underflow of the core timer T6 When timer T6 overflows from FFFF to 0000 when counting up or when it underflows from 0000 to FFFF when counting down the value stored in register CAPREL is loaded into timer T6 This will not set the interrupt request flag CRIR associated with the CAPREL register However interrupt request flag T6IR will be set indicating the overflow underflow of T6 CAPREL Register Interrupt Core Timer T6 Redis MCS03899 Figure 10 20 GPT2 Register CAPREL in Reload Mode Semiconductor Group 10 27 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT2 Capture Reload Register CAPREL in Capture And Re
14. Reload from register CAPREL Enabled Timer 6 Run Bit The timer can be started or stopped by software through bit T6R Timer T6 Run Bit If TGR 0 the timer stops Setting T6R to 1 will start the timer In gated timer mode the timer will only run if T6R 1 and the gate is active high or low as programmed Timer 6 Output Toggle Latch An overflow or underflow of timer T6 will clock the toggle bit T6OTL in control register T6CON T6OTL can also be set or reset by software T6OTL can be used in conjunction with the timer over underflows as an input for the counter function of the auxiliary timer T5 Semiconductor Group 10 21 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timer 6 in Timer Mode Timer mode for the core timer T6 is selected by setting bitfield T6M in register TECON to 000p In this mode T6 is clocked with the internal system clock divided by a programmable prescaler which is selected by bit field T6l The input frequency fre for timer T6 and its resolution rz are scaled linearly with lower clock frequencies fcpy as can be seen from the following formula f Jeru ius 4x p lt T6l gt T6 7 lt EN e 4 x 2716 i Jopu MHz Interrupt P ld Request Clock GPT2 Timer T6 Up Down Figure 10 17 Block Diagram of Core Timer T6 in Timer Mode The timer input frequencies resolution and periods which result from the selected prescaler option are listed
15. The SSC supports full duplex synchronous communication at up to 4 Mbaud 16 MHz CPU clock It may be configured so it interfaces with serially linked peripheral components A dedicated baud rate generator allows to set up all standard baud rates without oscillator tuning For transmission reception and error handling 3 separate interrupt vectors are provided The SSC transmits or receives characters of 2 16 bits length synchronously to a shift clock which can be generated by the SSC master mode or by an external master slave mode The SSC can start shifting with the LSB or with the MSB and allows the selection of shifting and latching clock edges as well as the clock polarity A number of optional hardware error detection capabilities has been included to increase the reliability of data transfers Transmit and receive error supervise the correct handling of the data buffer Phase and baudrate error detect incorrect serial data The On chip PC Bus Module The integrated IC Module handles the transmission and reception of frames over the two line IC bus in accordance with the PC Bus specification The on chip IC Module can receive and transmit data using 7 bit or 10 bit addressing and it can operate in slave mode in master mode or in multi master mode Several physical interfaces port pins can be established under software control Data can be transferred at speeds up to 400 Kbit sec Two interrupt nodes dedicated to the PC module al
16. are completed before entering the service routine The actual execution time for these instructions e g waitstates therefore influences the interrupt response time In the figure above the respective interrupt request flag is set in cycle 1 fetching of instruction N The indicated source wins the prioritization round during cycle 2 In cycle 3 a TRAP instruction is injected into the decode stage of the pipeline replacing instruction N 1 and clearing the source s interrupt request flag to 0 Cycle 4 completes the injected TRAP instruction save PSW IP and CSP if segmented mode and fetches the first instruction 11 from the respective vector location All instructions that entered the pipeline after setting of the interrupt request flag N 1 N 2 will be executed after returning from the interrupt service routine The minimum interrupt response time is 5 states 10 TCL This requires program execution from the internal code memory no external operand read requests and setting the interrupt request flag during the last state of an instruction cycle When the interrupt request flag is set during the first state of an instruction cycle the minimum interrupt response time under these conditions is 6 state times 12 TCL The interrupt response time is increased by all delays of the instructions in the pipeline that are executed before entering the service routine including N Semiconductor Group 5 16 1998 05 01 SIEMENS I
17. exchanges the transmit data with the receive data Since the clock line is connected to all slaves their shift registers will be shifted synchronously with the master s shift register shifting out the data contained in the registers and shifting in the data detected at the input line After the preprogrammed number of clock pulses via the data width selection the data transmitted by the master is contained in all slaves shift registers while the master s shift register holds the data of the selected slave In the master and all slaves the content of the shift register is copied into the receive buffer SSCRB and the receive interrupt flag SSCRIR is set A slave device will immediately output the selected first bit MSB or LSB of the transfer data at pin MRST when the content of the transmit buffer is copied into the slave s shift register It will not wait for the next clock from the baudrate generator as the master does The reason for this is that depending on the selected clock phase the first clock edge generated by the master may be already used to clock in the first data bit So the slave s first data bit must already be valid at this time Semiconductor Group 12 7 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI Note On the SSC always a transmission and a reception takes place at the same time regardless whether valid data has been transmitted or received This is different e g from asynchronous re
18. All interrupt requests may be enabled or disabled generally via bit IEN in register PSW This control bit is the main switch that selects if requests from any source are accepted or not For a specific request to be arbitrated the respective source s enable bit and the global enable bit must both be set The Priority Level automatically selects a certain group of interrupt requests that will be acknowledged disclosing all other requests The priority level of the source that won the arbitration is compared against the CPU s current level and the source is only serviced if its level is higher than the current CPU level Changing the CPU level to a specific value via software blocks all requests on the same or a lower level An interrupt source that is assigned to level 0 will be disabled and never be serviced The ATOMIC and EXTend instructions automatically disable all interrupt requests for the duration of the following 1 4 instructions This is useful e g for semaphore handling and does not require to re enable the interrupt system after the unseparable instruction sequence see chapter System Programming Interrupt Class Management An interrupt class covers a set of interrupt sources with the same importance i e the same priority from the system s viewpoint Interrupts of the same class must not interrupt each other The C161RI supports this function with two features Classes with up to 4 members can be established by using t
19. Figure 4 2 Sequential Instruction Pipelining Standard Branch Instruction Processing Instruction pipelining helps to speed sequential program processing In the case that a branch is taken the instruction which has already been fetched providently is mostly not the instruction which must be decoded next Thus at least one additional machine cycle is normally required to fetch the branch target instruction This extra machine cycle is provided by means of an injected instruction see figure below nots 1 Machine Injection Cycle Y EN Ls E OE j E EA ee ee ee PEE e e E o e ee eee om ME EET RU time Figure 4 3 Standard Branch Instruction Pipelining If a conditional branch is not taken there is no deviation from the sequential program flow and thus no extra time is required In this case the instruction after the branch instruction will enter the decode stage of the pipeline at the beginning of the next machine cycle after decode of the conditional branch instruction Semiconductor Group 4 4 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Cache Jump Instruction Processing The C161RI incorporates a jump cache to optimize conditional jumps which are processed repeatedly within a loop Whenever a jump on cache is taken the extra time to fetch the branch target instruction can be saved and thus the corresponding cache jump instruction in mos
20. The previously received character in the receive buffer is overwritten The Loop Back option selected by bit SOLB allows the data currently being transmitted to be received simultaneously in the receive buffer This may be used to test serial communication routines at an early stage without having to provide an external network In loop back mode the alternate input output functions of the Port 3 pins are not necessary Note Serial data transmission or reception is only possible when the Baud Rate Generator Run Bit SOR is set to 1 Otherwise the serial interface is idle Do not program the mode control field SOM in register SOCON to one of the reserved combinations to avoid unpredictable behavior of the serial interface Semiconductor Group 11 3 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI 11 1 Asynchronous Operation Asynchronous mode supports full duplex communication where both transmitter and receiver use the same data frame format and the same baud rate Data is transmitted on pin TXDO P3 10 and received on pin RXDO P3 11 These signals are alternate functions of Port 3 pins Reload Register Glock r ero 2 gt Baud Rate Timer H SOR SOPE SOFE 4 S0OE Clock Receive Int SUR Request Serial Port Control SOTIR diu Int RXDO P3 11 eques Error Int Shift Clock SOEIR Request Receive Shift Transmit Shift Register Register SOM SOSTP
21. The timer is counting downwards and can be started or stopped through the global enable bit SSCEN in register SSCCON Register SSCBR is the dual function Baud Rate Generator Reload register Reading SSCBR while the SSC is enabled returns the content of the timer Reading SSCBR while the SSC is disabled returns the programmed reload value In this mode the desired reload value can be written to SSCBR Note Never write to SSCBR while the SSC is enabled Semiconductor Group 12 10 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI The formulas below calculate either the resulting baud rate for a given reload value or the required reload value for a given baudrate foru foru Bsgo SSCBR 2 x lt SSCBR gt 1 2 x Baudratessc lt SSCBR gt represents the content of the reload register taken as unsigned 16 bit integer The maximum baud rate that can be achieved when using a CPU clock of 16 MHz is 4 MBaud The table below lists some possible baud rates together with the required reload values and the resulting bit times assuming a CPU clock of 16 MHz Baud Rate Bit Time Reload Value Reserved Use a reload value gt 0 0000 4 0 MBaud 250 ns 00014 2 67 MBaud 375 ns 00024 2 0 MBaud 500 ns 0003 1 6 MBaud 625 ns 0004 1 0 MBaud 1 us 0007 100 KBaud 10 us 004F 10 KBaud 100 us 031F 1 0 KBaud 1 ms 1F3F 122 1 Baud 8 2
22. read from bitfield CSSEL in register RPOH read only e g in order to check the configuration during run time The table below summarizes the alternate functions of Port 6 depending on the number of selected chip select lines coded via bitfield CSSEL Port 6 Pin Altern Function Altern Function Altern Function Altern Function CSSEL 10 CSSEL 01 CSSEL 00 CSSEL 11 P6 0 Gen purpose IO Chip select CSO Chip select CSO Chip select CSO P6 1 Gen purpose IO Chip select CST Chip select CS1 Chip select CST P6 2 Gen purpose IO Gen purpose IO Chip select CS2 Chip select CS2 P6 3 Gen purpose IO Gen purpose IO Gen purpose IO Chip select CS3 P6 4 Gen purpose IO Gen purpose IO Gen purpose IO Chip select CS4 P6 5 SDA1 PC bus data line 1 P6 6 SCL1 PC bus clock line 1 P6 7 SDA2 PC bus data line 2 Alternate Function P6 7 P6 6 P6 5 P6 4 P6 3 P6 2 P6 1 P6 0 General Purpose Input Output Figure 7 17 Port 6 IO and Alternate Functions Semiconductor Group 7 27 1998 05 01 SIEMENS Parallel Ports C161RI The chip select lines of Port 6 additionally have an internal weak pullup device This device is switched on always during reset for all potential CS output pins This feature is implemented to drive the chip select lines high during reset in order to avoid multiple chip selection After reset the CS function must be used if selected so In this case there i
23. sud nete ien P oped a bed owas Ene 20 11 20 5 Peripheral Control and Interface 00 00 eee 20 11 20 6 Floating Point S pport reis ia ord Rok rv eb lane ER 20 12 20 7 Trap Interrupt Entry and EXIU ue ook SSS ER AG BERS RE RR E Ost ROK 20 12 20 8 Unseparable Instruction Sequences 0 0 cece eee ee 20 12 20 9 Overriding the DPP Addressing Mechanism 0000 eee eee 20 13 20 10 Handling the Internal Code Memory eee eee ee 20 14 20 11 Pits ciitaps and MINGS 3 c sicui bi eta eem Frac ec oe Rt ose rele mo Da eae 20 15 21 Thie Heglster Seb cos oer sd urere ys eee ae hae HEE REID RE na 21 1 21 1 Register Description Formal p ERE A EXE EAR Heda be DER 21 1 21 2 CPU General Purpose Registers GPRs llllsssellslesss 21 2 21 3 Special Function Registers ordered by Name 00 0c eee eens 21 4 21 4 Registers ordered by Address 000 cece ee tee ee 21 9 21 5 leer oi Sw iso re T PITT 21 14 Semiconductor Group l 3 1998 05 01 SIEMENS G16 1R General Information Table of Contents Page 22 Instruction Set Summary 00 anaana 22 1 23 Device Specification 0 0 ee 23 1 24 Keyword Index cosi rx te oa nee wee ES E le eed 24 1 Semiconductor Group 4 1998 05 01 SIEMENS Introduction C161RI 1 Introduction The rapidly growing area of embedded control applications is representing one of the most time critical operating enviro
24. the interrupt node XP3IE 1 and the RTC subnode RTCIE 1 must be enabled Please note that the node request bit XP3IR is automatically cleared when the interrupt handler is vectored to while the subnode request bit T14IR must be cleared by software Semiconductor Group 14 3 1998 06 01 SIEMENS The Real Time Clock C161RI Defining the RTC Time Base The reload timer T14 determines the input frequency of the RTC timer i e the RTC time base as well as the T14 interrupt cycle time The table below lists the interrupt period range and the T14 reload values for a time base of 1 s and 1 ms for several oscillator frequencies RTC Interrupt Periods and Reload Values Oscillator RTC Interrupt Period Reload Value A Reload Value B Frequency Minimum Maximum T14REL Base TI4REL Base 32 768 KHz Aux 244 14 us 16 0s F000 1 000 s FFFC 0 977 ms 32 KHz Aux 250 us 16 38 s F060 1 000 s FFFC 1 000 ms 32 KHz Main 8000 us 524 29 s FF83 1 000s 4 MHz Main 64 0 us 4 195 C2F7 1 000s FFFO0 1 024 ms 5 MHz Main 51 2 us 3 35 s B3B5 0 999 s FFEC 1 024 ms 8 MHz Main 32 0 us 2 10s 85EE 1 000 s FFE1 0 992 ms 10 MHz Main 25 6 us 1 68 s 676A 0 999 s FFD9 0 998 ms 12 MHz Main 21 3 us 1 40 s 48E5 1 000s FFD2 1 003 ms 16 MHz Main 16 0 us 1 05 s OBDC 1 000 s FFC2 0 992 ms Increased RTC Accuracy through Software Correction The accuracy of
25. the other is programmed for a reload on a negative transition of T3OTL With this combination the core timer is alternately reloaded from the two auxiliary timers The figure below shows an example for the generation of a PWM signal using the alternate reload mechanism T2 defines the high time of the PWM signal reloaded on positive transitions and T4 defines the low time of the PWM signal reloaded on negative transitions The PWM signal can be output on TSOUT with TSOE 1 port latch 1 and direction bit 1 With this method the high and low time of the PWM signal can be varied in a wide range Note The output toggle latch T3OTL is accessible via software and may be changed if required to modify the PWM signal However this will NOT trigger the reloading of T3 Reload Register T2 Interrupt gt T2iR Request Y QU gt Core Timer T3 T30TL e eo X 52 d 1 Up Down TIOE Interrupt TSIR Request r Interrupt TAIR Request t Reload Register T4 T4I MCB02037 Note Lines only affected by over underflows of T3 but NOT by software modifications of T3OTL Figure 10 13 GPT1 Timer Reload Configuration for PWM Generation Note Although it is possible it should be avoided to select the same reload trigger event for both auxiliary timers In this case both reload registers would try to load the core timer at the same time If this combination is selected T2 is d
26. 00 FCE8 00 FCF6 00 FCE6 00 FCFA 00 FCEA 00 FCF2 00 FCE2 00 FCFO 00 FCEO Figure 5 2 Mapping of PEC Pointers into the Internal RAM PEC data transfers do not use the data page pointers DPP3 DPPO The PEC source and destination pointers are used as 16 bit intra segment addresses within segment 0 so data can be transferred between any two locations within the first four data pages 3 0 The pointer locations for inactive PEC channels may be used for general data storage Only the required pointers occupy RAM locations Note If word data transfer is selected for a specific PEC channel i e BWT 0 the respective source and destination pointers must both contain a valid word address which points to an even byte boundary Otherwise the Illegal Word Access trap will be invoked when this channel is used Semiconductor Group 5 12 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 3 Prioritization of Interrupt and PEC Service Requests Interrupt and PEC service requests from all sources can be enabled so they are arbitrated and serviced if they win or they may be disabled so their requests are disregarded and not serviced Enabling and disabling interrupt requests may be done via three mechanisms Control Bits allow to switch each individual source ON or OFF so it may generate a request or not The control bits xxIE are located in the respective interrupt control registers
27. 1 Bsync lt SOBRL gt represents the content of the reload register taken as unsigned 13 bit integers lt SOBRS gt represents the value of bit SOBRS i e 0 or 1 taken as integer The maximum baud rate that can be achieved in synchronous mode when using a CPU clock of 16 MHz is 2 MBaud Semiconductor Group 11 11 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI 11 5 ASCO Interrupt Control Four bit addressable interrupt control registers are provided for serial channel ASCO Register SOTIC controls the transmit interrupt SOTBIC controls the transmit buffer interrupt SORIC controls the receive interrupt and SOEIC controls the error interrupt of serial channel ASCO Each interrupt source also has its own dedicated interrupt vector SOTINT is the transmit interrupt vector SOTBINT is the transmit interrupt vector SORINT is the receive interrupt vector and SOEINT is the error interrupt vector The cause of an error interrupt request framing parity overrun error can be identified by the error status flags in control register SOCON Note In contrary to the error interrupt request flag SOEIR the error status flags SOFE SOPE SOOE are not reset automatically upon entry into the error interrupt service routine but must be cleared by software SOTIC FF6C B6 SFR Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SORIC FF6E B7 SFR TRES 7 SOEIC FF70 B8 SFR Res
28. 1 1998 05 01 SIEMENS The General Purpose Timer Units C161RI All three timers of block GPT1 T2 T3 T4 can run in 4 basic modes which are timer gated timer counter and incremental interface mode and all timers can either count up or down Each timer has an alternate input function pin TxIN associated with it which serves as the gate control in gated timer mode or as the count input in counter mode The count direction Up Down may be programmed via software or may be dynamically altered by a signal at an external control input pin Each overflow underflow of core timer T3 is latched in the toggle FlipFlop T3OTL and may be indicated on an alternate output function pin The auxiliary timers T2 and T4 may additionally be concatenated with the core timer or used as capture or reload registers for the core timer The current contents of each timer can be read or modified by the CPU by accessing the corresponding timer registers T2 T3 or T4 which are located in the non bitaddressable SFR space When any of the timer registers is written to by the CPU in the state immediately before a timer increment decrement reload or capture is to be performed the CPU write operation has priority in order to guarantee correct results T UID CPU Clock SUT TIENTS dp OC n 2 nz3 10 T2 T2IN Mode Reload Control Capture gt CPU Clock 9 n 3 10 3 Toggle FF Mode GPT1 Timer T3 TBIN Con
29. 10 4 5 CPU Special Function Registers 0 0 00 eee eee 4 11 5 Interrupt and Trap Functions 0 0 0 ee 5 1 5 1 Interrupt System Structure isses ev RM wee wa tae Vee RE ens 5 2 5 2 Interrupt Control Registers 2 25 5 once ineat t tcp de eto pete tns 5 5 5 3 Operation of the PEC Channels 2 000 eee 5 10 5 4 Prioritization of Interrupt and PEC Service Requests 055 5 13 5 5 Saving the Status during Interrupt Service llle 5 14 5 6 Interrupt Response Times seo cee aaa 5 16 5 7 PEG Response TIMES os i pias us ex tur me ROS E a E T 2 AE 5 18 5 8 Interrupt Node Sharing asian UR aaaea 5 20 5 9 Extaral Interr pIs onnon 2 Ses ate ROR RA e E Mie A abc ER 5 21 5 10 Tap FUNCIONS Sansan ettet E ete dor aa es he aceite wate 5 24 6 Clock Generation 0 000 c ce ee 6 1 6 1 iG olio CE 6 2 6 2 FreaiencyGontFol suaeqasse Sora etie Dn EUR PROS E Gem ertet ep eE dr RS 6 3 6 3 Clock Divers oou kh Mee hu adhe pexe DR YE CENE ERE Ree DDS 6 6 7 P aralle POSi ri a toes Sid Chee Se wade tup t aep Durant Oh ou 7 1 7 1 PORTO re angenan a aaa a aa aaa a her CHEER A a RISE is 7 6 7 2 Alternate Functions of PORTO ok ER i ee eee eS eee ye SAN a 7 7 7 3 POBI S eit eaa equ pesi beset ais TR Bs ee ee GE avatars Gea be ewe aie IM 7 9 Semiconductor Group l 1 1998 05 01 SIEMENS C161RI General Information Table of Contents Alternate Functions of PORT1 Alternate Functions of P
30. 16 bit Mux Bus 3 6 3 3 8 bit Demux Bus 4 8 4 4 8 bit Mux Bus 6 12 6 6 Execution from the internal RAM provides flexibility in terms of loadable and modifiable code on the account of execution time Execution from external memory strongly depends on the selected bus mode and the programming of the bus cycles waitstates The operand and instruction accesses listed below can extend the execution time of an instruction Internal code memory operand reads same for byte and word operand reads Internal RAM operand reads via indirect addressing modes Internal SFR operand reads immediately after writing External operand reads External operand writes Jumps to non aligned double word instructions in the internal ROM space Testing Branch Conditions immediately after PSW writes Semiconductor Group 4 10 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI 4 4 CPU Special Function Registers The core CPU requires a set of Special Function Registers SFRs to maintain the system state information to supply the ALU with register addressable constants and to control system and bus configuration multiply and divide ALU operations code memory segmentation data memory paging and accesses to the General Purpose Registers and the System Stack The access mechanism for these SFRs in the CPU core is identical to the access mechanism for any other SFR Since all SFRs can simply be controlled by means of any i
31. 32 16 signed R3 holds divisor JMPR cc V ERROR Test for divide overflow MOV R3 MDH Move remainder to R3 MOV R4 MDL Move integer result to R4 Clears MDRIU Whenever a multiply or divide instruction is interrupted while in progress the address of the interrupted instruction is pushed onto the stack and the MULIP flag in the PSW of the interrupting routine is set When the interrupt routine is exited with the RETI instruction this bit is implicitly tested before the old PSW is popped from the stack If MULIP 1 the multiply divide instruction is re read from the location popped from the stack return address and will be completed after the RETI instruction has been executed Note The MULIP flag is part of the context of the interrupted task When the interrupting routine does not return to the interrupted task e g scheduler switches to another task the MULIP flag must be set or cleared according to the context of the task that is switched to BCD Calculations No direct support for BCD calculations is provided in the C161RI BCD calculations are performed by converting BCD data to binary data performing the desired calculations using standard data types and converting the result back to BCD data Due to the enhanced performance of division instructions binary data is quickly converted to BCD data through division by 105 Conversion from BCD data to binary data is enhanced by multiple bit shift instructions This provides similar per
32. 4 Std Function Altern Function Altern Function Altern Function Pin SALSEL 0164 KB SALSEL 11256KB SALSEL 00 1 MB SALSEL 10 4 MB P4 0 Gen purpose IO Seg Address A16 Seg Address A16 Seg Address A16 P4 1 Gen purpose IO Seg Address A17 Seg Address A17 Seg Address A17 P4 2 Gen purpose IO Gen purpose IO Seg Address A18 Seg Address A18 P4 3 Gen purpose IO Gen purpose IO Seg Address A19 Seg Address A19 P4 4 Gen purpose IO Gen purpose IO Gen purpose IO Seg Address A20 P4 5 Gen purpose IO Gen purpose IO Gen purpose IO Seg Address A21 P4 6 Gen purpose IO Gen purpose IO Gen purpose IO Seg Address A22 Alternate Function a Port 4 P4 6 A22 P4 5 A21 P4 4 A20 P4 3 A19 P4 2 A18 P4 1 A17 P4 0 A16 General Purpose Input Output Figure 7 13 Port 4 IO and Alternate Functions Semiconductor Group 7 21 1998 05 01 SIEMENS Parallel Ports C161RI Write DP4 y Direction Latch Read DP4 y Alternate Function Enable Write P4 y Alternate Data Output MUX e 0 I n t e r n a l Port Output Latch Read P4 y 1 KHH 0 e Alternate Data 4 Input Figure 7 14 Block Diagram of a Port 4 Pin Semiconductor Group 7 22 gt Output Buffer MCB02075 1998 05 01 SIEMENS Parallel Ports C161RI 7 6 Port 5 This 6 bit input port can only read data There is no output l
33. 7 Port6 If this 8 bit port is used for general purpose IO the direction of each line can be configured via the corresponding direction register DP6 Each port line can be switched into push pull or open drain mode via the open drain control register ODP6 P6 FFCC E6 SFR Reset Value 00 WU ML LUNES 8 7 6 5 4 3 2 1 0 i rw rw rw rw rw rw rw rw Bit Function P6 y Port data register P6 bit y DP6 FFCE E7 SFR Reset Value 00 9 8 7 6 5 4 3 2 1 0 x B rw rw rw rw rw rw rw rw Bit Function DP6 y Port direction register DP6 bit y DP6 y 0 Port line P6 y is an input high impedance DP6 y 1 Port line P6 y is an output ODP6 F1CE E7 ESFR Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ODP6 ODP6 ODP6 ODP6 ODP6 4 2 1 0 3 rw rw rw rw rw Bit Function ODP6 y Port 6 Open Drain control register bit y ODP6 y 0 Port line P6 y output driver in push pull mode ODP6 y 1 Port line P6 y output driver in open drain mode Semiconductor Group 7 26 1998 05 01 Parallel Ports C161RI SIEMENS Alternate Functions of Port 6 A programmable number of chip select signals CS4 CS0 derived from the bus control registers BUSCONA BUSCONO can be output on 5 pins of Port 6 The other 3 pins may be used for C Bus interface lines The number of chip select signals is selected via PORTO during reset The selected value can be
34. Bus Type Pins POL 7 and POL 6 BUSTYP select the external bus type during reset if an external start is selected via pin EA This allows the configuration of the external bus interface of the C161RI even for the first code fetch after reset The two bits are copied into bit field BTYP of register BUSCONO POL 7 controls the data bus width while POL 6 controls the address output multiplexed or demultiplexed This bit field may be changed via software after reset if required BTYP Encoding External Data Bus Width External Address Bus Mode 00 8 bit Data Demultiplexed Addresses 0 1 8 bit Data Multiplexed Addresses 10 16 bit Data Demultiplexed Addresses 11 16 bit Data Multiplexed Addresses PORTO and PORT are automatically switched to the selected bus mode In multiplexed bus modes PORTO drives both the 16 bit intra segment address and the output data while PORT1 remains in high impedance state as long as no demultiplexed bus is selected via one of the BUSCON registers In demultiplexed bus modes PORT1 drives the 16 bit intra segment address while PORTO or POL according to the selected data bus width drives the output data For a 16 bit data bus BHE is automatically enabled for an 8 bit data bus BHE is disabled via bit BYTDIS in register SYSCON Default 16 bit data bus with multiplexed addresses Note If an internal start is selected via pin EA these two pins are disregarded and bit field BTYP of register BUSC
35. Instruction Pipelining The instruction pipeline of the C161RI partitiones instruction processing into four stages of which each one has its individual task 1st gt FETCH In this stage the instruction selected by the Instruction Pointer IP and the Code Segment Pointer CSP is fetched from either the internal ROM internal RAM or external memory 2nd DECODE In this stage the instructions are decoded and if required the operand addresses are calculated and the respective operands are fetched For all instructions which implicitly access the system stack the SP register is either decremented or incremented as specified For branch instructions the Instruction Pointer and the Code Segment Pointer are updated with the desired branch target address provided that the branch is taken 3rd 5EXECUTE In this stage an operation is performed on the previously fetched operands in the ALU Additionally the condition flags in the PSW register are updated as specified by the instruction All explicit writes to the SFR memory space and all auto increment or auto decrement writes to GPRs used as indirect address pointers are performed during the execute stage of an instruction too 4th gt WRITE BACK In this stage all external operands and the remaining operands within the internal RAM space are written back A particularity of the C161RI are the so called injected instructions These injected instructions are generated internally by th
36. PEC channel number is accessed independent of the current DPP register contents and also the locations referred to by these pointers are accessed independent of the current DPP register contents If a PEC channel is not used the corresponding pointer locations area available and can be used for word or byte data storage For more details about the use of the source and destination pointers for PEC data transfers see section Interrupt and Trap Functions Semiconductor Group 3 7 1998 05 01 SIEMENS Memory Organization C161RI Special Function Registers The functions of the CPU the bus interface the IO ports and the on chip peripherals of the C161RI are controlled via a number of so called Special Function Registers SFRs These SFRs are arranged within two areas of 512 Byte size each The first register block the SFR area is located in the 512 Bytes above the internal RAM 00 FFFF 00 FE00 the second register block the Extended SFR ESFR area is located in the 512 Bytes below the internal RAM 00 F1FF 00 F000 Special function registers can be addressed via indirect and long 16 bit addressing modes Using an 8 bit offset together with an implicit base address allows to address word SFRs and their respective low bytes However this does not work for the respective high bytes Note Writing to any byte of an SFR causes the non addressed complementary byte to be cleared The upper half of each register block is bit
37. POL 7 and POL 6 bit BUSACTO in register BUSCONO is set to 1 bit ALECTLO in register BUSCONO is set to 1 bit ROMEN in register SYSCON will be cleared to 0 bit BYTDIS in register SYSCON is set according to the data bus width bit WRCFG in register SYSCON is set according to pin POH O WRC When an internal start is selected pin EA 17 register BUSCONO is cleared to 0000 bit ROMEN in register SYSCON will be set to 1 bit BYTDIS in register SYSCON is cleared i e BHE WRH is enabled bit WRCFG in register SYSCON is set according to pin POH O WRC The other bits of register BUSCONO and the other BUSCON registers are cleared This default initialization selects the slowest possible external accesses using the configured bus type When the internal reset has completed the configuration of PORTO PORT1 Port 4 Port 6 and of the BHE signal High Byte Enable alternate function of P3 12 depends on the bus type which was selected during reset When any of the external bus modes was selected during reset PORTO will operate in the selected bus mode Port 4 will output the selected number of segment address lines all zero after reset and Port 6 will drive the selected number of CS lines CSO will be 0 while the other active CS lines will be 1 When no memory accesses above 64 K are to be performed segmentation may be disabled When the on chip bootstrap loader was activated during reset
38. Register 0000 T4CON b FF44 A2 GPT1 Timer 4 Control Register 0000 T4IC b FF64 B2 GPT1 Timer 4 Interrupt Control Register 0000 T5 FE46 23 GPT2 Timer 5 Register 0000 T5CON b FF46 A3 GPT2 Timer 5 Control Register 0000 T5IC b FF66 B3 GPT2 Timer 5 Interrupt Control Register 0000 T6 FE48 24 GPT2 Timer 6 Register 0000 T6CON b FF48 A4 GPT2 Timer 6 Control Register 0000 T6IC b FF68 B4 GPT2 Timer 6 Interrupt Control Register 0000 TFR b FFAC D6 Trap Flag Register 0000 WDT FEAE 57 Watchdog Timer Register read only 0000 WDTCON b FFAE D74 Watchdog Timer Control Register 00XX XPOIC b F186 E C3 FC Data Interrupt Control Register 0000 Semiconductor Group 21 7 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value XP1IC b F18E E C7 FC Protocol Interrupt Control Register 0000 XP2IC b F196 E CB X Peripheral 2 Interrupt Control Register 0000 XP3IC b F19E E CF RTC Interrupt Control Register 0000 ZEROS b FF1C 8E Constant Value 0 s Register read only 0000 The system configuration is selected during reset 2 The reset value depends on the indicated reset source Semiconductor Group 21 8 1998 05 01 SIEMENS The Reg ister Set C161RI 21 4 Registers ordered by Address The following table lists all SFRs which are implemented in the C161RI ordered by their physical address Bit addressable SFRs
39. SOBRL reload value from the timer contents The formula below shows the association T6 36 9 SOBRL 3725 T6 z Semiconductor Group 15 5 1998 05 01 SIEMENS The Bootstrap Loader C161RI For a correct data transfer from the host to the C161RI the maximum deviation between the internal initialized baudrate for ASCO and the real baudrate of the host should be below 2 5 The deviation Fg in percent between host baudrate and C161RI baudrate can be calculated via the formula below Boontr n B nost Contr 100 96 Fa 2 5 96 Note Function Fg does not consider the tolerances of oscillators and other devices supporting the serial communication This baudrate deviation is a nonlinear function depending on the CPU clock and the baudrate of the host The maxima of the function Fg increase with the host baudrate due to the smaller baudrate prescaler factors and the implied higher quantization error see figure below 2 5 Q PN nei V M NM Blow B High P uost MCA02260 Figure 15 3 Baudrate deviation between host and C161RI The minimum baudrate B in the figure above is determined by the maximum count capacity of timer T6 when measuring the zero byte i e it depends on the CPU clock Using the maximum T6 count 2 6 in the formula the minimum baudrate for fopy 16 MHz is 549 Baud The lowest standard baudrate in this case would be 600 Baud Baudrates below B would
40. STUTRAP 0000184 06 I Class B Hardware Traps Undefined Opcode UNDOPC BTRAP 00 0028 OA Protected Instruction PRTFLT BTRAP 00 0028 OA Fault Illegal Word Operand ILLOPA BTRAP 00 0028 OA Access Illegal Instruction Access ILLINA BTRAP 00 0028 OA Illegal External Bus ILLBUS BTRAP 00 0028 OA Access Reserved 2C 3C 0B OF 4 Software Traps Any Any Current TRAP Instruction 0000004 00 7F CPU 00 01FC Priority in steps of 4 Semiconductor Group 5 4 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Normal Interrupt Processing and PEC Service During each instruction cycle one out of all sources which require PEC or interrupt processing is selected according to its interrupt priority This priority of interrupts and PEC requests is programmable in two levels Each requesting source can be assigned to a specific priority A second level called group priority allows to specify an internal order for simultaneous requests from a group of different sources on the same priority level At the end of each instruction cycle the one source request with the highest current priority will be determined by the interrupt system This request will then be serviced if its priority is higher than the current CPU priority in register PSW Interrupt System Register Description Interrupt processing is controlled globally by register PSW through a general interrupt enable bit IEN and the CPU prio
41. See description After that the bus pin drivers and the IO pin drivers are switched off tristate The internal reset procedure requires 516 CPU clock cycles in order to perform a complete reset sequence This 516 cycle reset sequence is started upon a watchdog timer overflow a SRST instruction or when the reset input signal RSTIN is latched low hardware reset The internal reset condition is active at least for the duration of the reset sequence and then until the RSTIN input is inactive When this internal reset condition is removed reset sequence complete RSTIN inactive the reset configuration is latched from PORTO and RD and then pins ALE RD and WR are driven to their inactive levels Note Bit ADP which selects the Adapt mode is latched with the rising edge of RSTIN After the internal reset condition is removed the microcontroller will start program execution from memory location 00 0000 in code segment zero This start location will typically hold a branch instruction to the start of a software initialization routine for the application specific configuration of peripherals and CPU Special Function Registers 7 C161RI oZ RSTOUT X yy External Hardware Vcc jj External Reset Cp amp Reset Sources a Generated Warm reset b Automatic Power on reset MCA02259 Figure 18 1 External Reset Circuitry Semiconductor Group 18 1 1998 06 01 SIEMENS Sy
42. The system stack is also located within the on chip RAM area and it is accessed by the CPU via the stack pointer SP register Two separate SFRs STKOV and STKUN are implicitly compared against the stack pointer value upon each stack access for the detection of a stack overflow or underflow Semiconductor Group 2 7 1998 05 01 SIEMENS Architectural Overview C161RI Hardware detection of the selected memory space is placed at the internal memory decoders and allows the user to specify any address directly or indirectly and obtain the desired data without using temporary registers or special instructions A 2 KByte 16 bit wide on chip XRAM provides fast access to user data variables user stacks and code The on chip XRAM is realized as an X Peripheral and appears to the software as an external RAM Therefore it cannot store register banks and is not bitaddressable The XRAM allows 16 bit accesses with maximum speed For Special Function Registers 1024 Bytes of the address space are reserved The standard Special Function Register area SFR uses 512 bytes while the Extended Special Function Register area ESFR uses the other 512 bytes E SFRs are wordwide registers which are used for controlling and monitoring functions of the different on chip units Unused E SFR addresses are reserved for future members of the C166 family with enhanced functionality External Bus Interface In order to meet the needs of designs where more memory is
43. USRO User General Purpose Flag May be used by the application software HLDEN Interrupt and EBC Control Fields ILVL IEN Define the response to interrupt requests and enable external bus arbitration Described in section Interrupt and Trap Functions ALU Status N C V Z E MULIP The condition flags N C V Z E within the PSW indicate the ALU status due to the last recently performed ALU operation They are set by most of the instructions due to specific rules which depend on the ALU or data movement operation performed by an instruction After execution of an instruction which explicitly updates the PSW register the condition flags cannot be interpreted as described in the following because any explicit write to the PSW register supersedes the condition flag values which are implicitly generated by the CPU Explicitly reading the PSW register supplies a read value which represents the state of the PSW register after execution of the immediately preceding instruction Note After reset all of the ALU status bits are cleared Semiconductor Group 4 14 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI N Flag For most of the ALU operations the N flag is set to 1 if the most significant bit of the result contains a 1 otherwise it is cleared In the case of integer operations the N flag can be interpreted as the sign bit of the result negative N 1 positive N 0 Negative n
44. XP3INT 00 010C 43 675 Semiconductor Group 5 3 1998 05 01 Interrupt and Trap Functions C161RI SIEMENS The table below lists the vector locations for hardware traps and the corresponding status flags in register TFR It also lists the priorities of trap service for cases where more than one trap condition might be detected within the same instruction After any reset hardware reset software reset instruction SRST or reset by watchdog timer overflow program execution starts at the reset vector at location 00 0000 Reset conditions have priority over every other system activity and therefore have the highest priority trap priority III Software traps may be initiated to any vector location between 00 0000 and 00 01FC A service routine entered via a software TRAP instruction is always executed on the current CPU priority level which is indicated in bit field ILVL in register PSW This means that routines entered via the software TRAP instruction can be interrupted by all hardware traps or higher level interrupt requests Exception Condition Trap Trap Vector Trap Trap Flag Vector Location Number Priority Reset Functions Hardware Reset RESET 00 0000 00 I Software Reset RESET 00 0000 00 III Watchdog Timer Over RESET 00 0000 00 I flow Class A Hardware Traps Non Maskable Interrupt NMI NMITRAP 00 0008 02 Stack Overflow STKOF STOTRAP 00 0010 04 I Stack Underflow STKUF
45. accesses on a GPR the GPR s word address is calculated as just described but the position of the bit within the word is specified by a separate additional 4 bit value Semiconductor Group 4 23 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Specified by reg or bitoff Context 1111 4 Bit GPR Pointer Address Internal RAM Control gt Must be within the internal RAM area For byte GPR For word GPR accesses accesses MCD02005 Figure 4 8 Implicit CP Use by Short GPR Addressing Modes The Stack Pointer SP This non bit addressable register is used to point to the top of the internal system stack TOS The SP register is pre decremented whenever data is to be pushed onto the stack and it is post incremented whenever data is to be popped from the stack Thus the system stack grows from higher toward lower memory locations Since the least significant bit of register SP is tied to 0 and bits 15 through 12 are tied to 1 by hardware the SP register can only contain values from F000 to FFFE This allows to access a physical stack within the internal RAM of the C161RI A virtual stack usually bigger can be realized via software This mechanism is supported by registers STKOV and STKUN see respective descriptions below The SP register can be updated via any instruction which is capable of modifying an SFR Note Due to the internal instruction pipeline a POP or RETURN in
46. addressable so the respective control status bits can directly be modified or checked using bit addressing When accessing registers in the ESFR area using 8 bit addresses or direct bit addressing an Extend Register EXTR instruction is required before to switch the short addressing mechanism from the standard SFR area to the Extended SFR area This is not required for 16 bit and indirect addresses The GPRs R15 RO are duplicated ie they are accessible within both register blocks via short 2 4 or 8 bit addresses without switching ESFR SWITCH EXAMPLE EXTR 4 Switch to ESFR area for next 4 instr MOV ODP2 datal6 ODP2 uses 8 bit reg addressing BFLDL DP6 mask data8 Bit addressing for bit fields BSET DP1H 7 Bit addressing for single bits MOV T8REL R1 T8REL uses 16 bit mem address R1 is duplicated into the ESFR space EXTR is not required for this access poss j The scope of the EXTR 4 instruction ends here MOV T8REL R1 T8REL uses 16 bit mem address R1 is accessed via the SFR space In order to minimize the use of the EXTR instructions the ESFR area mostly holds registers which are mainly required for initialization and mode selection Registers that need to be accessed frequently are allocated to the standard SFR area wherever possible Note The tools are equipped to monitor accesses to the ESFR area and will automatically insert EXTR instructions or issue a warning in
47. are marked with the letter b in column Name SFRs within the Extended SFR Space ESFRs are marked with the letter E in column Physical Address Registers within on chip X Peripherals are marked with the letter X in column Physical Address Name Physical 8 Bit Description Reset Address Address Value ICCFG EDOO X FC Configuration Register XXy ICCON EDO2 X FC Control Register UUUU ICST EDOA X FC Status Register UUUU ICADR EDO6 X FC Address Register XX01 ICRTB ED08 X FC Receive Transmit Buffer UFUU IDPROG F078 E 3C Identifier 0000 IDMEM F07A E 3D Identifier 0000 IDCHIP F07C E 3E Identifier 09XX IDMANUF F07E E 3F Identifier 1820 SSCTB FOBO E58 SSC Transmit Buffer write only 0000 SSCRB FOB2 E59 SSC Receive Buffer read only XXXXy SSCBR FOBA E 5A SSC Baudrate Register 0000 T14REL FODO E 68 RTC Timer 14 Reload Register XXXXy T14 FOD2 E 69 RTC Timer 14 Register XXXXy RTCL FOD4 E 6A RTC Low Register XXXX RTCH FOD6 E 6B RTC High Register XXXX DPOL b F100 E 80 POL Direction Control Register 00 DPOH b F102 E 81 POH Direction Control Register 00 DP1L b F104 E82 P1L Direction Control Register 00 DP1H b F106 E83 P1H Direction Control Register 00 RPOH b F108 E 84 System Startup Configuration Register Rd only XX XPOIC b F186 E C3 X Peripheral 0 Inter
48. banks can only reside within the internal RAM All GPRs are bit addressable Name Physical 8 Bit Description Reset Address Address Value RO CP 0 F0 CPU General Purpose Word Register RO UUUU R1 CP 2 Fi CPU General Purpose Word Register R1 UUUU R2 CP 4 F2 CPU General Purpose Word Register R2 UUUU R3 CP 6 F3 CPU General Purpose Word Register R3 UUUU R4 CP 8 FA CPU General Purpose Word Register R4 UUUU R5 CP 10 F5 CPU General Purpose Word Register R5 UUUU R6 CP 12 F6 CPU General Purpose Word Register R6 UUUU R7 CP 14 F7 CPU General Purpose Word Register R7 UUUU R8 CP 16 F8 CPU General Purpose Word Register R8 UUUU R9 CP 18 F9 CPU General Purpose Word Register R9 UUUU R10 CP 20 FA CPU General Purpose Word Register R10 UUUU R11 CP 22 FB CPU General Purpose Word Register R11 UUUU R12 CP 24 FC CPU General Purpose Word Register R12 UUUU R13 CP 26 FD CPU General Purpose Word Register R13 UUUU R14 CP 28 FE CPU General Purpose Word Register R14 UUUU R15 CP 30 FF CPU General Purpose Word Register R15 UUUU Semiconductor Group 21 2 1998 05 01 SIEMENS The Register Set C161RI The first 8 GPRs R7XRO may also be accessed bytewise Other than with SFRs writing to a GPR byte does not affect the other byte of the respective GPR The respective halves of
49. banks can physically exist within the internal RAM at the same time Only the register bank selected by the Context Pointer register CP is active at a given time however Selecting a new active register bank is simply done by updating the CP register A particular Switch Context SCXT instruction performs register bank switching and an automatic saving of the previous context The number of implemented register banks arbitrary sizes is only limited by the size of the available internal RAM Details on using switching and overlapping register banks are described in chapter System Programming Semiconductor Group 3 6 1998 05 01 SIEMENS Memory Organization C161RI PEC Source and Destination Pointers The 16 word locations in the internal RAM from 00 FCEO to 00 FCFE just below the bit addressable section are provided as source and destination address pointers for data transfers on the eight PEC channels Each channel uses a pair of pointers stored in two subsequent word locations with the source pointer SRCPx on the lower and the destination pointer DSTPx on the higher word address x 7 0 O0 FCFE y 00 FCFE y 00 FCFC H 00 FCE0 H 00 FCDE p PEC Source and Destination Pointers Internal RAM 00 FCE2 H 00 F600 H MCD03903 Figure 3 4 Location of the PEC Pointers Whenever a PEC data transfer is performed the pair of source and destination pointers which is selected by the specified
50. bit wise programmable as inputs or outputs via direction registers The IO ports are true bidirectional ports which are switched to high impedance state when configured as inputs The output drivers of three IO ports can be configured pin by pin for push pull operation or open drain operation via control registers During the internal reset all port pins are configured as inputs All port lines have programmable alternate input or output functions associated with them PORTO and PORT1 may be used as address and data lines when accessing external memory while Port 4 outputs the additional segment address bits A22 19 17 A16 in systems where segmentation is used to access more than 64 KBytes of memory Port 6 provides IC Bus lines and the chip select signals CS4 CSO Port 2 accepts the fast external interrupt inputs Port 3 includes alternate functions of timers serial interfaces the optional bus control signal BHE and the system clock output CLKOUT Port 5 is used for timer control signals and for the analog inputs to the A D Converter All port lines that are not used for these alternate functions may be used as general purpose IO lines Semiconductor Group 2 10 1998 05 01 SIEMENS Architectural Overview C161RI Serial Channels Serial communication with other microcontrollers processors terminals or external peripheral components is provided by two serial interfaces with different functionality an Asynchronous Synchronous Se
51. bitfield MOD in register ICCON The physical channel is configured by a control word written to register ICCFG defining the active interface pins and the used baudrate It is recommended to have only one SDA and SCL line active at a time when operating in slave mode The address by which the slave module can be selected is written to register ICADR The FC module is selected by another master when it receives after a start condition either its own device address stored in ICADR or the general call address 00 In this case an interrupt is generated and bit SLA in register ICST is set indicating the valid selection The desired transfer mode is then selected via bit TRX TRX 0 for reception TRX 1 for transmission For a transmission the respective data byte is placed into the buffer ICRTB which automatically sets bit TRX and the acknowledge behavior is selected via bit ACKDIS For a reception the respective data byte is fetched from the buffer ICRTB after IRQD has been activated In both cases the data transfer itself is enabled by clearing bit IRQP which releases the SCL line When a stop condition is detected bit SLA is cleared Semiconductor Group 17 7 1998 05 01 2 SIEMENS The I2C Bus Module C161RI The I C bus configuration register ICCFG selects the bus baudrate as well as the activation of SDA and SCL lines So an external I C channel can be established baudrate and physical lines with one single regis
52. by a set of SFRs as summarized below Those portions of port and direction registers which are used for alternate functions by the GPT2 block are shaded Ports amp Direction Control Data Registers Control Registers Interrupt Control Alternate Functions T5CON T6CON CAPIN P3 2 ODP3 Port 3 Open Drain Control Register T5 GPT2 Timer 5 Register DP3 Port 3 Direction Control Register T6 GPT2 Timer 6 Register P3 Port 3 Data Register CAPREL GPT2 Capture Reload Register T5CON GPT2 Timer 5 Control Register T5IC GPT2 Timer 5 Interrupt Control Register T6CON GPT2 Timer 6 Control Register T6IC GPT2 Timer 6 Interrupt Control Register CRIC GPT2 CAPREL Interrupt Control Register Figure 10 15 SFRs and Port Pins Associated with Timer Block GPT2 Timer block GPT2 supports high precision event control with a maximum resolution of 8 TCL It includes the two timers T5 and T6 and the 16 bit capture reload register CAPREL Timer T6 is referred to as the core timer and T5 is referred to as the auxiliary timer of GPT2 The count direction Up Down may be programmed via software An overflow underflow of T6 is indicated by the output toggle bit T6OTL In addition T6 may be reloaded with the contents of CAPREL The toggle bit also supports the concatenation of T6 with auxiliary timer T5 Triggered by an external signal the contents of T5 can be captured into register CAPREL and T5 may optionally be cleared Both timer T6 and T5 can count up
53. by the selected slave is avoided when all slaves which are not selected for transmission to the master only send ones 1 Since this high level is not actively driven onto the line but only held through the pullup device the selected slave can pull this line actively to a low level when transmitting a zero bit The master selects the slave device from which it expects data either by separate select lines or by sending a special command to this slave After performing all necessary initializations of the SSC the serial interfaces can be enabled For a master device the alternate clock line will now go to its programmed polarity The alternate data line will go to either 0 or 1 until the first transfer will start After a transfer the alternate data line will always remain at the logic level of the last transmitted data bit When the serial interfaces are enabled the master device can initiate the first data transfer by writing the transmit data into register SSCTB This value is copied into the shift register which is assumed to be empty at this time and the selected first bit of the transmit data will be placed onto the MTSR line on the next clock from the baudrate generator transmission only starts if SSCEN 1 Depending on the selected clock phase also a clock pulse will be generated on the SCLK line With the opposite clock edge the master at the same time latches and shifts in the data detected at its input line MRST This
54. by writing to the Transmit Buffer register SOTBUF via an instruction or a PEC data transfer Only the number of data bits which is determined by the selected operating mode will actually be transmitted i e bits written to positions 9 through 15 of register SOTBUF are always insignificant After a transmission has been completed the transmit buffer register is cleared to 0000 Data transmission is double buffered so a new character may be written to the transmit buffer register before the transmission of the previous character is complete This allows the transmission of characters back to back without gaps Data reception is enabled by the Receiver Enable Bit SOREN After reception of a character has been completed the received data and if provided by the selected operating mode the received parity bit can be read from the read only Receive Buffer register SORBUF Bits in the upper half of SORBUF which are not valid in the selected operating mode will be read as zeros Data reception is double buffered so that reception of a second character may already begin before the previously received character has been read out of the receive buffer register In all modes receive buffer overrun error detection can be selected through bit SOOEN When enabled the overrun error status flag SOOE and the error interrupt request flag SOEIR will be set when the receive buffer register has not been read by the time reception of a second character is complete
55. can be defined within the C161Rl s address space may partly overlap each other Thus e g small areas may be cut out of bigger windows in order to effectively utilize external resources especially within segment 0 For each access the EBC compares the current address with all address select registers programmable ADDRSELx and hardwired XADRSx This comparison is done in four levels Priority 1 The hardwired XADRSx registers are evaluated first A match with one of these registers directs the access to the respective X Peripheral using the corresponding XBCONXx register and ignoring all other ADDRSELx registers Priority 2 Registers ADDRSEL2 and ADDRSELA are evaluated before ADDRSEL1 and ADDRSELS respectively A match with one of these registers directs the access to the respective external area using the corresponding BUSCONXx register and ignoring registers ADDRSEL 1 3 see figure below Priority 3 A match with registers ADDRSEL1 or ADDRSEL3 directs the access to the respective external area using the corresponding BUSCONXx register Priority 4 If there is no match with any XADRSx or ADDRSELx register the access to the external bus uses register BUSCONO XBCONO BUSCON2 E BUSCON4 BUSCON1 BUSCONS3 BUSCONO Active Window Inactive Window Figure 9 11 Address Window Arbitration Note Only the indicated overlaps are defined All other overlaps lead to erroneous bus cycles E g ADDRSEL4 may not overlap ADDRSEL2 o
56. different modes such as gated timer or counter mode or may be concatenated with another timer of the same block The auxiliary timers of GPT1 may optionally be configured as reload or capture registers for the core timer In the GPT2 block the additional CAPREL register supports capture and reload operation with extended functionality and its core timer T6 may be concatenated with timers of the CAPCOM units TO T1 T7 and T8 Each block has alternate input output functions and specific interrupts associated with it 10 1 Timer Block GPT1 From a programmer s point of view the GPT1 block is composed of a set of SFRs as summarized below Those portions of port and direction registers which are used for alternate functions by the GPT1 block are shaded Ports amp Direction Control Data Registers Control Registers Interrupt Control Alternate Functions T2IN P3 7 T2EUD P5 15 TSIN P3 6 TSEUD P3 4 T4IN P3 5 T4EUD P5 14 TSOUT P3 3 ODP3 Port 3 Open Drain Control Register T2 GPT1 Timer 2 Register DP3 Port 3 Direction Control Register T3 GPT1 Timer 3 Register P3 Port 3 Data Register T4 GPT1 Timer 4 Register T2CON GPT1 Timer 2 Control Register T2IC GPT1 Timer 2 Interrupt Control Register T3CON GPT1 Timer 3 Control Register T3IC GPT1 Timer 3 Interrupt Control Register T4CON GPT1 Timer 4 Control Register T4IC GPT1 Timer 4 Interrupt Control Register Figure 10 1 SFRs and Port Pins Associated with Timer Block GPT1 Semiconductor Group 10
57. each single instruction including its operand data type condition flag settings addressing modes length number of bytes and object code format is provided in the Instruction Set Manual for the C166 Family This manual also provides tables ordering the instructions according to various criteria to allow quick references Summary of Instruction Classes Grouping the various instruction into classes aids in identifying similar instructions e g SHR ROR and variations of certain instructions e g ADD ADDB This provides an easy access to the possibilities and the power of the instructions of the C161Hl Note The used mnemonics refer to the detailed description Arithmetic Instructions Addition of two words or bytes ADD ADDB Addition with Carry of two words or bytes ADDC ADDCB Subtraction of two words or bytes SUB SUBB Subtraction with Carry of two words or bytes SUBC SUBCB 16 16 bit signed or unsigned multiplication MUL MULU 16 16 bit signed or unsigned division DIV DIVU 32 16 bit signed or unsigned division DIVL DIVLU 1 s complement of a word or byte CPL CPLB 2 s complement negation of a word or byte NEG NEGB Logical Instructions Bitwise ANDing of two words or bytes AND ANDB Bitwise ORing of two words or bytes OR ORB Bitwise XORing of two words or bytes XOR XORB Compare and Loop Control Instructions Comparison of two words or bytes CMP CMPB Comparison of two words
58. ensured that there is enough excess space on the stack for saving the current system state PSW IP in segmented mode also CSP twice Otherwise a system reset should be generated Semiconductor Group 5 26 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Stack Underflow Trap Whenever the stack pointer is incremented to a value which is greater than the value in the stack underflow register STKUN the STKUF flag is set in register TFR and the CPU will enter the stack underflow trap routine Again which IP value will be pushed onto the system stack depends on which operation caused the increment of the SP When an implicit increment of the SP is made through a POP or return instruction the IP value pushed is the address of the following instruction When the SP is incremented by an add instruction the pushed IP value represents the address of the instruction after the instruction following the add instruction Undefined Opcode Trap When the instruction currently decoded by the CPU does not contain a valid C161RI opcode the UNDOPC flag is set in register TFR and the CPU enters the undefined opcode trap routine The IP value pushed onto the system stack is the address of the instruction that caused the trap This can be used to emulate unimplemented instructions The trap service routine can examine the faulting instruction to decode operands for unimplemented opcodes based on the stacked IP In order to resume processing the sta
59. flag is set depending on the value of the source operand to signify whether the end of a search table is reached or not If the value of the source operand of an instruction equals the lowest negative number which is representable by the data format of the corresponding instruction 8000 for the word data type or 80 for the byte data type the E flag is set to 1 otherwise it is cleared MULIP Flag The MULIP flag will be set to 1 by hardware upon the entrance into an interrupt service routine when a multiply or divide ALU operation was interrupted before completion Depending on the state of the MULIP bit the hardware decides whether a multiplication or division must be continued or not after the end of an interrupt service The MULIP bit is overwritten with the contents of the stacked MULIP flag when the return from interrupt instruction RETI is executed This normally means that the MULIP flag is cleared again after that Note The MULIP flag is a part of the task environment When the interrupting service routine does not return to the interrupted multiply divide instruction i e in case of a task scheduler that switches between independent tasks the MULIP flag must be saved as part of the task environment and must be updated accordingly for the new task before this task is entered Semiconductor Group 4 16 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI CPU Interrupt Status IEN ILVL The Interru
60. i e its corresponding direction control bit DP3 4 must be set to 0 GPT1 Core Timer T3 Count Direction Control Pin TXEUD Bit TxUDE Bit TxUD Count Direction X 0 0 Count Up X 0 1 Count Down 0 1 0 Count Up 1 1 0 Count Down 0 1 1 Count Down 1 1 1 Count Up Note The direction control works the same for core timer T3 and for auxiliary timers T2 and T4 Therefore the pins and bits are named Tx Timer 3 Output Toggle Latch An overflow or underflow of timer T3 will clock the toggle bit T3OTL in control register T3CON TSOTL can also be set or reset by software Bit T3OE Alternate Output Function Enable in register T3CON enables the state of T3OTL to be an alternate function of the external output pin T3OUT For that purpose a 1 must be written into the respective port data latch and pin T3OUT must be configured as output by setting the corresponding direction control bit to 1 If T3OE 1 pin T3OUT then outputs the state of T3OTL If TSOE 0 pin T3OUT can be used as general purpose IO pin In addition T3OTL can be used in conjunction with the timer over underflows as an input for the counter function or as a trigger source for the reload function of the auxiliary timers T2 and T4 For this purpose the state of TSOTL does not have to be available at pin T3OUT because an internal connection is provided for this option Semiconductor Group 10 4 1998 05 01 SIEMENS The Gen
61. in the figure below at lower frequencies it may be left open This termination improves the operation of the oscillator by filtering out frequencies above the intended oscillator frequency XTAL1 XTAL2 15pF 3ko Input clock Figure 6 3 Oscillator Output Termination Note It is strongly recommended to measure the oscillation allowance or margin in the final target system layout to determine the optimum parameters for the oscillator operation The external circuitry is different from that required by previous derivatives Semiconductor Group 6 2 1998 05 01 SIEMENS Clock Generation C161RI 6 2 Frequency Control The CPU clock is generated from the oscillator clock in either of two software selectable ways The basic clock is the standard operating clock for the C161RI and is required to deliver the intended maximum performance The configuration via PORTO CLKCFG after a long hardware reset determines one of two possible basic clock generation modes e Direct Drive the oscillator clock is directly fed to the controller hardware Prescaler the oscillator clock is divided by 2 to achieve a 50 duty cycle The Slow Down clock is the oscillator clock divided by a programmable factor of 1 32 This alternate possibility runs the C161RI at a lower frequency depending on the programmed slow down factor and thus greatly reduces its power consumption Configuration s Oscillator clock CPU
62. in the table below This table also applies to the auxiliary timer T5 in timer mode Note that some numbers may be rounded to 3 significant digits GPT2 Timer Input Frequencies Resolution and Periods JScpy 20 MHz Timer Input Selection T5I T6l 0005 001 010 0115 100 101 110 111 Prescaler factor 4 8 16 32 64 128 256 512 Input Frequency 5 2 5 1 25 625 312 5 156 25 78 125 39 06 MHz MHz MHz kHz kHz kHz kHz kHz Resolution 200 ns 400ns 800ns 1 6us 3 2us 6 4us 12 8 us 25 6 us Period 13ms 26ms 52 5ms 105 ms 210 ms 420 ms 840 ms 1 68 s Note Bitfield T6M in register TECON will be 000 after reset Do not modify this bitfield to any other value Semiconductor Group 10 22 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT2 Auxiliary Timer T5 The auxiliary timer T5 can be configured for timer mode with the same options for the timer frequencies as the core timer T6 In addition the auxiliary timer can be concatenated with the core timer operation in counter mode Its contents may be captured to register CAPREL upon a selectable trigger The individual configuration for timer T5 is determined by its bitaddressable control register T5ECON Note that functions which are present in both timers of block GPT2 are controlled in the same bit positions and in the same manner in each of the specific control registers Note The auxiliary timer has no output
63. inputs The output drivers of three IO ports 2 3 6 can be configured pin by pin for push pull operation or open drain operation via control registers The logic level of a pin is clocked into the input latch once per state time regardless whether the port is configured for input or output A write operation to a port pin configured as an input causes the value to be written into the port output latch while a read operation returns the latched state of the pin itself A read modify write operation reads the value of the pin modifies it and writes it back to the output latch Writing to a pin configured as an output DPx y 1 causes the output latch and the pin to have the written value since the output buffer is enabled Reading this pin returns the value of the output latch A read modify write operation reads the value of the output latch modifies it and writes it back to the output latch thus also modifying the level at the pin Data Input Output Direction Control Threshold Open Drain Registers Registers Control Registers DPOL E DPOH E DP1L DP1H E PICON E ODP2 E ODP3 E P5DIDIS Figure 7 1 SFRs and Pins associated with the Parallel Ports Semiconductor Group 7 1 1998 05 01 SIEMENS Parallel Ports C161RI Open Drain Mode In the C161RI certain ports provide Open Drain Control which allows to switch the output driver of a port pin from a push pull configuration to an open drain
64. internal RAM to be used for program data or register banking This approach assumes no error but requires a set of control routines see below Semiconductor Group 20 4 1998 05 01 System Programming C161RI SIEMENS Circular virtual Stack This basic technique allows pushing until the overflow boundary of the internal stack is reached At this point a portion of the stacked data must be saved into external memory to create space for further stack pushes This is called stack flushing When executing a number of return or pop instructions the upper boundary since the stack empties upward to higher memory locations is reached The entries that have been previously saved in external memory must now be restored This is called stack filling Because procedure call instructions do not continue to nest infinitely and call and return instructions alternate flushing and filling normally occurs very infrequently If this is not true for a given program environment this technique should not be used because of the overhead of flushing and filling The basic mechanism is the transformation of the addresses of a virtual stack area controlled via registers SP STKOV and STKUN to a defined physical stack area within the internal RAM via hardware This virtual stack area covers all possible locations that SP can point to i e 00 F000 through 00 FFFE STKOV and STKUN accept the same 4 KByte address range The size of the physical stack a
65. loaded into SOTBUF is immediately moved to the transmit shift register thus freeing SOTBUF for the next data to be sent This is indicated by the transmit buffer interrupt request flag SOTBIR being set SOTBUF may now be loaded with the next data while transmission of the previous one is still going on The data bits are transmitted synchronous with the shift clock After the bit time for the 8th data bit both pins TXDO and RXDO will go high the transmit interrupt request flag SOTIR is set and serial data transmission stops Pin TXDO P3 10 must be configured for alternate data output i e P3 10 2 1 and DP3 10 2 1 in order to provide the shift clock Pin RXDO P3 11 must also be configured for output P3 11 1 and DP3 11 1 during transmission Synchronous reception is initiated by setting bit SOREN 1 If bit SOR 1 the data applied at pin RXDO are clocked into the receive shift register synchronous to the clock which is output at pin TXDO After the 8th bit has been shifted in the content of the receive shift register is transferred to the receive data buffer SORBUF the receive interrupt request flag SORIR is set the receiver enable bit SOREN is reset and serial data reception stops Pin TXDO P3 10 must be configured for alternate data output i e P3 10 2 1 and DP3 10 1 in order to provide the shift clock Pin RXDO P3 11 must be configured as alternate data input DP3 11 0 Synchronous reception is stopped b
66. mode via the open drain control register ODP2 P2 FFCO E0 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 rw rw rw rw rw rw rw rw i gt 5 Bit Function P2 y Port data register P2 bit y DP2 FFC2 Elp SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DP2 rw rw rw rw rw rw rw rw x Bit Function DP2 y Port direction register DP2 bit y DP2 y 0 Port line P2 y is an input high impedance DP2 y 1 Port line P2 y is an output ODP2 F1C2 E1 ESFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ODP2 ODP2 ODP2 10 9 8 rw rw rw rw rw rw rw rw Bit Function ODP2 y Port 2 Open Drain control register bit y ODP2 y 0 Port line P2 y output driver in push pull mode ODP2 y 1 Port line P2 y output driver in open drain mode Semiconductor Group 7 12 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Functions of Port 2 All Port 2 lines P2 15 P2 8 serve as external interrupt inputs EX7IN EXOIN 16 TCL sample rate The table below summarizes the alternate functions of Port 2 Port 2 Pin Alternate Function b P2 8 EXOIN Fast External Interrupt 0 Input P2 9 EX1IN Fast External Interrupt 1 Input P2 10 EX2IN Fast External Interrupt 2 Input P2 11 EX3IN Fast External Interrupt 3 Input P2 12 EX4IN Fast External Interrupt 4 Input P2 13 EX5IN Fast External Interrupt 5 Input P2 14 EX6IN Fast Externa
67. number of transmitted bits is also received Transmit data is written into the Transmit Buffer SSCTB It is moved to the shift register as soon as this is empty An SSC master SSCMS 1 immediately begins transmitting while an SSC slave SSCMS 0 will wait for an active shift clock When the transfer starts the busy flag SSCBSY is set and a transmit interrupt request SSCTIR will be generated to indicate that SSCTB may be reloaded again When the programmed number of bits 2 16 has been transferred the contents of the shift register are moved to the Receive Buffer SSCRB and a receive interrupt request SSCRIR will be generated If no further transfer is to take place SSCTB is empty SSCBSY will be cleared at the same time Software should not modify SSCBSY as this flag is hardware controlled Semiconductor Group 12 4 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI Note Only one SSC etc can be master at a given time The transfer of serial data bits can be programmed in many respects the data width can be chosen from 2 bits to 16 bits transfer may start with the LSB or the MSB the shift clock may be idle low or idle high data bits may be shifted with the leading or trailing edge of the clock signal the baudrate may be set from 122 Bd up to 4 MBd 16 MHz CPU clock the shift clock can be generated master or received slave This allows the adaptation of the SSC to a wid
68. oN a a o a aseo XT XT L w N S ES EN a T WR s Read Write Delay 1 The Data drivers from the previous bus cycle should be disabled when the RD signal becomes active MCT02066 Figure 9 9 Read Write Delay The read write delay is controlled via the RWDCx bits in the BUSCON registers The command s will be delayed if bit RWDOx is 0 default after reset Semiconductor Group 9 14 1998 06 01 SIEMENS The External Bus Interface C161RI 9 3 READY Controlled Bus Cycles For situations where the programmable waitstates are not enough or where the response access time of a peripheral is not constant the C161RI provides external bus cycles that are terminated via a READY input signal synchronous or asynchronous In this case the C161RI first inserts a programmable number of waitstates 0 7 and then monitors the READY line to determine the actual end of the current bus cycle The external device drives READY low in order to indicate that data have been latched write cycle or are available read cycle Bus Cycle Bus Cycle he with active READY TUS extended via READY zu 1 WS 2 WS 1 WS 2 WS ALE RD WR SREADY Y Y A A AREADY A A MCD02237 A Evaluation sampling of the READY input Figure 9 10 READY Controlled Bus Cycles The READY function is enabled via th
69. one more pin with an alternate output function However its structure is slightly different see figure below because after reset the BHE or WRH function must be used depending on the system startup configuration In these cases there is no possibility to program any port latches before Thus the appropriate alternate function is selected automatically If BHE WRH is not used in the system this pin can be used for general purpose IO by disabling the alternate function BYTDIS 1 WRCFG 0 ZN Write DP3 x 4 1 Direct MUX irection Latch a gt 0 I Read DP3 x Alternate Function t Enable e r a P3 12 BHE n Write P3 x Alternate a Data 1 P3 15 CLKOUT Output MUX A 7 Port Output gt lo Output B Latch Buffer u S Read P3 x Clock Input Latch MCB02073 Figure 7 12 Block Diagram of Pins P3 15 CLKOUT and P3 12 BHE WRH Note Enabling the BHE or WRH function automatically enables the P3 12 output driver Setting bit DP3 12 1 is not required Enabling the CLKOUT function automatically enables the P3 15 output driver Setting bit DP3 15 1 is not required Semiconductor Group 7 19 1998 05 01 SIEMENS Parallel Ports C161RI 7 5 Port4 If this 7 bit port is used for general purpose IO the direction of each line can be configured via the corresponding direction register DP4 P4 FFC8 E4 SFR Reset Value 00 8 7 6 5 4
70. or down and the current timer value can be read or modified by the CPU in the non bitaddressable SFRs T5 and T6 Semiconductor Group 10 19 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Ede Interrupt di Request CAPIN Interrupt Request Interrupt pm Request CPU Clock GPT2 Timer T6 Figure 10 16 GPT2 Block Diagram Semiconductor Group 10 20 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT2 Core Timer T6 The operation of the core timer T6 is controlled by its bitaddressable control register T6CON T6CON FF48 A4 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 rw rw rw rw rw rw Bit Function T6l Timer 6 Input Selection Depends on the Operating Mode see respective sections T6M Timer 6 Mode Control Basic Operating Mode 000 Timer Mode 001 Reserved Do not use this combination 010 Reserved Do not use this combination 011 Reserved Do not use this combination 1XX Reserved Do not use this combination T6R Timer 6 Run Bit T6R 2 0 Timer Counter 6 stops T6R 1 JTimer Counter 6 runs T6UD Timer 6 Up Down Control T6UD 0 Timer Counter 6 counts up T6UD 1 Timer Counter 6 counts down T6OTL Timer 6 Output Toggle Latch Toggles on each overflow underflow of T6 Can be set or reset by software T6SR Timer 6 Reload Mode Enable T6SR 0 Reload from register CAPREL Disabled T6SR 1
71. required than is provided on chip up to 8 MBytes of external RAM and or ROM can be connected to the microcontroller via its external bus interface The integrated External Bus Controller EBC allows to access external memory and or peripheral resources in a very flexible way For up to five address areas the bus mode multiplexed demultiplexed the data bus width 8 bit 16 bit and even the length of a bus cycle waitstates signal delays can be selected independently This allows to access a variety of memory and peripheral components directly and with maximum efficiency If the device does not run in Single Chip Mode where no external memory is required the EBC can control external accesses in one of the following external access modes 16 18 20 23 bit Addresses 16 bit Data Demultiplexed 16 18 20 23 bit Addresses 8 bit Data Demultiplexed 16 18 20 23 bit Addresses 16 bit Data Multiplexed 16 18 20 23 bit Addresses 8 bit Data Multiplexed The demultiplexed bus modes use PORT1 for addresses and PORTO for data input output The multiplexed bus modes use PORTO for both addresses and data input output Port 4 is used for the upper address lines A16 if selected Important timing characteristics of the external bus interface waitstates ALE length and Read Write Delay have been made programmable to allow the user the adaption of a wide range of different types of memories and or peripherals Access to very slow m
72. reserved combination 11 is changed to 10 by hardware However it is not recommended to use this combination The PEC Transfer Count Field COUNT controls the action of a respective PEC channel where the content of bit field COUNT at the time the request is activated selects the action COUNT may allow a specified number of PEC transfers unlimited transfers or no PEC service at all The table below summarizes how the COUNT field itself the interrupt requests flag IR and the PEC channel action depends on the previous content of COUNT Previous Modified IR after Action of PEC Channel COUNT COUNT PEC service and Comments FF FF 0 Move a Byte Word Continuous transfer mode i e COUNT is not modified FE 02 FD4 01 0 Move a Byte Word and decrement COUNT 01 00 T Move a Byte Word Leave request flag set which triggers another request 00 00 1 No action Activate interrupt service routine rather than PEC channel The PEC transfer counter allows to service a specified number of requests by the respective PEC channel and then when COUNT reaches 00 activate the interrupt service routine which is associated with the priority level After each PEC transfer the COUNT field is decremented and the request flag is cleared to indicate that the request has been serviced Continuous transfers are selected by the value FF in bit field COUNT In this case COUNT is not mo
73. reset PORTO is configured to input and each line is held high through an internal pullup device Each line can now be individually pulled to a low level see DC level specifications in the respective Data Sheets through an external pulldown device A default configuration is selected when the respective PORTO lines are at a high level Through pulling individual lines to a low level this default can be changed according to the needs of the applications The internal pullup devices are designed such that an external pulldown resistors see Data Sheet specification can be used to apply a correct low level These external pulldown resistors can remain connected to the PORTO pins also during normal operation however care has to be taken such that they do not disturb the normal function of PORTO this might be the case for example if the external resistor is too strong With the end of reset the selected bus configuration will be written to the BUSCONO register The configuration of the high byte of PORTO will be copied into the special register RPOH This read only register holds the selection for the number of chip selects and segment addresses Software can read this register in order to react according to the selected configuration if required When the reset is terminated the internal pullup devices are switched off and PORTO will be switched to the appropriate operating mode During external accesses in multiplexed bus modes PORTO first o
74. resources designed around the CPU The combination of CPU and these resources results in the high performance of the members of this controller family Peripheral Event Controller PEC and Interrupt Control The Peripheral Event Controller allows to respond to an interrupt request with a single data transfer word or byte which only consumes one instruction cycle and does not require to save and restore the machine status Each interrupt source is prioritized every machine cycle in the interrupt control block If PEC service is selected a PEC transfer is started If CPU interrupt service is requested the current CPU priority level stored in the PSW register is tested to determine whether a higher priority interrupt is currently being serviced When an interrupt is acknowledged the current state of the machine is saved on the internal system stack and the CPU branches to the system specific vector for the peripheral The PEC contains a set of SFRs which store the count value and control bits for eight data transfer channels In addition the PEC uses a dedicated area of RAM which contains the source and destination addresses The PEC is controlled similar to any other peripheral through SFRs containing the desired configuration of each channel An individual PEC transfer counter is implicitly decremented for each PEC service except forming in the continuous transfer mode When this counter reaches zero a standard interrupt is performed to the ve
75. saved restored during interrupt entry exit 1 Segmentation disabled Only IP is saved restored ROMS1 Internal ROM Mapping 0 Internal ROM area mapped to segment 0 00 0000 00 7FFF 1 Internal ROM area mapped to segment 1 01 0000 01 7FFF STKSZ System Stack Size Selects the size of the system stack in the internal RAM from 32 to 1024 words Note Register SYSCON cannot be changed after execution of the EINIT instruction Bit SGTDIS controls the correct stack operation push pop of CSP or not during traps and interrupts Semiconductor Group 9 18 1998 06 01 SIEMENS The External Bus Interface C161RI The layout of the five BUSCON registers is identical Registers BUSCONA BUSCON1 which control the selected address windows are completely under software control while register BUSCONDO which e g is also used for the very first code access after reset is partly controlled by hardware i e it is initialized via PORTO during the reset sequence This hardware control allows to define an appropriate external bus for systems where no internal program memory is provided BUSCONO FOC 88 SFR Reset Value 0XX0 14 11 1 0 CSW CSR RDY BUS ALE MTT RWD BUSCON1 Cn Bay SFR Reset Value 0000 14 11 1 0 CSW CSR RDY Xs ALE MTT RWD BUSCON2 Fr aB SFR Reset Value 0000 14 11 1 0 CSW CSR RDY BUS ALE MTT RWD BUSCON3 cris 869 SFR Reset Value 0000 14 11 1 0 CS
76. signals are provided from bits six and seven of the ALU result to correctly set the condition flags Multiple precision arithmetic is provided through a CARRY IN signal to the ALU from previously calculated portions of the desired operation Most internal execution blocks have been optimized to perform operations on either 8 bit or 16 bit quantities Once the pipeline has been filled one instruction is completed per machine cycle except for multiply and divide An advanced Booth algorithm has been incorporated to allow four bits to be multiplied and two bits to be divided per machine cycle Thus these operations use two coupled 16 bit registers MDL and MDH and require four and nine machine cycles respectively to perform a 16 bit by 16 bit or 32 bit by 16 bit calculation plus one machine cycle to setup and adjust the operands and the result Even these longer multiply and divide instructions can be interrupted during their execution to allow for very fast Semiconductor Group 2 3 1998 05 01 SIEMENS Architectural Overview C161RI interrupt response Instructions have also been provided to allow byte packing in memory while providing sign extension of bytes for word wide arithmetic operations The internal bus structure also allows transfers of bytes or words to or from peripherals based on the peripheral requirements A set of consistent flags is automatically updated in the PSW after each arithmetic logical shift or movement operation
77. so interrupt nodes receive equal names throughout the architecture See register description below CCxIC See Table SFR Reset Value 00 9r 4 q9 8 MT E Bt et dde ues So 28 Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Fast External Interrupt Control Register Addresses Register Address External Interrupt CC8IC FF88 C4 EXOIN CC9IC FF8A C5 EX1IN CC10IC FF8C C6 EX2IN CC111C FF8E C7 EXSIN CC121C FF90 C8 EXAIN CC13IC FF92 C9 EX5IN CC14IC FF94 CA EX6IN CC15IC FF96 CB EX7IN Semiconductor Group 5 23 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 7 Trap Functions Traps interrupt the current execution similar to standard interrupts However trap functions offer the possibility to bypass the interrupt system s prioritization process in cases where immediate system reaction is required Trap functions are not maskable and always have priority over interrupt requests on any priority level The C161RI provides two different kinds of trapping mechanisms Hardware traps are triggered by events that occur during program execution e g illegal access or undefined opcode software traps are initiated via an instruction within the current execution flow Software Traps The TRAP instruction is used to cause a software call to an interrupt service routine The trap number that is speci
78. special modes 18 10 Write Control 18 11 Context Switching 5 15 Conversion analog digital 16 1 timing control 16 5 Count direction 10 4 Counter 10 7 10 13 10 24 CP 4 22 CPU 2 2 4 1 CRIC 10 29 CSP 4 18 1998 05 01 SIEMENS Keyword Index C161RI D G Data Page 4 20 20 13 GPR 3 6 4 22 21 2 boundaries 3 11 GPT 2 12 Delay GPT1 10 1 Read Write 9 14 GPT2 10 19 Demultiplexed Bus 9 4 Development Support 1 6 H Direct Drive 6 4 Half Duplex 12 8 Direction Hardware count 10 4 Reset 18 1 Disable Traps 5 24 Interrupt 5 13 Peripheral 19 11 I Segmentation 4 13 I C Bus Module 17 1 Division 4 27 20 1 ICADR 17 11 DPOL DPOH 7 6 ICCFG 17 8 DP1L DP1H 7 9 ICRTB 17 11 DP2 7 12 ICST 17 10 DP3 7 15 Idle DP4 7 20 Mode 19 2 DP6 7 26 State Bus 9 25 DPP 4 20 20 13 Incremental Interface 10 8 Indication of reset source 13 4 E Input threshold 7 3 Early chip select 9 9 Instruction 20 1 22 1 Emulation Mode 18 9 Bit Manipulation 22 2 Enable Branch 4 4 Interrupt 5 13 Pipeline 4 3 Peripheral 19 11 protected 22 4 Segmentation 4 13 Timing 4 10 Error Detection unseparable 20 12 ASCO 11 10 Interface SSC 12 12 CAN 2 11 EXICON 5 22 External Bus 9 1 External lC Bus 17 1 Bus 2 8 serial async gt ASCO 11 1 Bus Characteristics 9 10 to 9 16 serial sync gt SSC 12 1 Bus Idle State 9 25 Internal RAM 3 4 Bus Modes 9 2 to 9 7 Fast interrupts 5 22 Interrupts 5 21 F Fast external interrupts 5 22 Flags 4 14 to 4 16 Full Duplex 12 6 Semiconducto
79. table below For Boolean bit operations with only one operand the V flag is always cleared For Boolean bit operations with two operands the V flag represents the logical ORing of the two specified bits Semiconductor Group 4 15 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Shift Right Rounding Error Evaluation C Flag V Flag Rounding Error Quantity 0 0 No rounding error 0 1 0 Rounding error lt lI LSB 1 0 Rounding error LSB 1 1 Rounding error gt LSB e Z Flag The Z flag is normally set to 1 if the result of an ALU operation equals zero otherwise it is cleared For the addition and subtraction with carry the Z flag is only set to 1 if the Z flag already contains a 1 and the result of the current ALU operation additionally equals zero This mechanism is provided for the support of multiple precision calculations For Boolean bit operations with only one operand the Z flag represents the logical negation of the previous state of the specified bit For Boolean bit operations with two operands the Z flag represents the logical NORing of the two specified bits For the prioritize ALU operation the Z flag indicates if the second operand was zero or not e E Flag The E flag can be altered by instructions which perform ALU or data movement operations The E flag is cleared by those instructions which cannot be reasonably used for table search operations In all other cases the E
80. table below summarizes the possible combinations GPT1 Core Timer T3 Incremental Interface Mode Count Direction Level on respective TSIN Input TSEUD Input other input Rising Falling Rising Falling High Down Up Up Down Low Up Down Down Up The figures below give examples of T3 s operation visualizing count signal generation and direction control It also shows how input jitter is compensated which might occur if the sensor rests near to one of its switching points Semiconductor Group 10 9 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Forward Jitter Backward Jitter Forward TSIN Contents of T3 Note This example shows the timer behaviour assuming that T3 counts upon any transition on any input ie T3I 011 Figure 10 8 Evaluation of the Incremental Encoder Signals Forward Jitter Backward Jitter Forward Contents of T3 Note This example shows the timer behaviour assuming that T3 counts upon any transition on input T3IN ie T3l 001 Figure 10 9 Evaluation of the Incremental Encoder Signals Note Timer T3 operating in incremental interface mode automatically provides information on the sensor s current position Dynamic information speed acceleration deceleration may be obtained by measuring the incoming signal periods This is facilitated by an additional special capture mode for timer T5 Se
81. the C161RI s RTC is determined by the oscillator frequency and by the respective prescaling factor excluding or including T14 The accuracy limit generated by the prescaler is due to the quantization of a binary counter where the average is zero while the accuracy limit generated by the oscillator frequency is due to the difference between ideal and real frequency and therefore accumulates over time The total accuracy of the RTC can be further increased via software for specific applications that demand a high time accuracy The key to the improved accuracy is the knowledge of the exact oscillator frequency The relation of this frequency to the expected ideal frequency is a measure for the RTC s deviation The number N of cycles after which this deviation causes an error of 1 cycle can be easily computed So the only action is to correct the count by 1 after each series of N cycles This correction may be applied to the RTC register as well as to T14 Also the correction may be done cyclic e g within T14 s interrupt service routine or by evaluating a formula when the RTC registers are read for this the respective last RTC value must be available somewhere Note For the majority of applications however the standard accuracy provided by the RTC s structure will be more than sufficient Semiconductor Group 14 4 1998 06 01 SIEMENS The Bootstrap Loader C161RI 15 The Bootstrap Loader The built in bootstrap loade
82. the selected baud rate A majority decision of the 7th 8th and 9th sample determines the effective bit value This avoids erroneous results that may be caused by noise If the detected value is not a 0 when the start bit is sampled the receive circuit is reset and waits for the next 1 to 0 transition at pin RXDO If the start bit proves valid the receive circuit continues sampling and shifts the incoming data frame into the receive shift register When the last stop bit has been received the content of the receive shift register is transferred to the receive data buffer register SORBUF Simultaneously the receive interrupt request flag SORIR is set after the 9th sample in the last stop bit time slot as programmed regardless whether valid stop bits have been received or not The receive circuit then waits for the next start bit 1 to 0 transition at the receive data input pin The receiver input pin RXDO P3 11 must be configured for input i e DP3 11 0 Asynchronous reception is stopped by clearing bit SOREN A currently received frame is completed including the generation of the receive interrupt request and an error interrupt request if appropriate Start bits that follow this frame will not be recognized Note In wake up mode received frames are only transferred to the receive buffer register if the 9th bit the wake up bit is 1 If this bit is 0 no receive interrupt request will be activated and no data will b
83. toggle latch and no alternate output function T5CON FF46 A3 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 T5 T5 rw rw rw rw rw rw rw rw rw Bit Function T5lI Timer 5 Input Selection Depends on the Operating Mode see respective sections T5M Timer 5 Mode Control Basic Operating Mode 00 Timer Mode 01 Counter Mode 10 Reserved Do not use this combination 11 Reserved Do not use this combination T5R Timer 5 Run Bit 0 Timer Counter 5 stops 1 Timer Counter 5 runs T5UD Timer 5 Up Down Control T5UD 0 Timer Counter 5 counts up T5UD2 1 Timer Counter 5 counts down CT3 Timer 3 Capture Trigger Enable 0 Capture trigger from pin CAPIN 1 Capture trigger from T3 input pins CI Register CAPREL Capture Trigger Selection depending on bit CT3 00 Capture disabled 01 Positive transition rising edge on CAPIN or any transition on T3IN 10 Negative transition falling edge on CAPIN or any transition on T3EUD 11 Any transition rising or falling edge on CAPIN or any transition on T3IN or T3EUD Semiconductor Group 10 23 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Bit Function T5CLR Timer 5 Clear Bit 0 Timer 5 not cleared on a capture 1 Timer 5 is cleared on a capture T5SC Timer 5 Capture Mode Enable 0 Capture into register CAPREL disabled 1 Capture into register CAPREL enabled Timer T5 in Counter Mode Counter mode fo
84. up procedure is always monitored The software has to be designed to service the Watchdog Timer before it overflows If due to hardware or software related failures the software fails to do so the Watchdog Timer overflows and generates an internal hardware reset and pulls the RSTOUT pin low in order to allow external hardware components to reset The Watchdog Timer is a 16 bit timer clocked with the CPU clock divided either by 2 or by 128 The high byte of the Watchdog Timer register can be set to a prespecified reload value stored in WDTREL in order to allow further variation of the monitored time interval Each time it is serviced by the application software the high byte of the Watchdog Timer is reloaded Thus time intervals between 31 us and 525 ms can be monitored 16 MHz The default Watchdog Timer interval after reset is 8 19 ms 16 MHz Semiconductor Group 2 12 1998 05 01 SIEMENS Architectural Overview C161RI A D Converter For analog signal measurement an 8 bit A D converter with 4 multiplexed input channels and a sample and hold circuit has been integrated on chip It uses the method of successive approximation The sample time for loading the capacitors and the conversion time is programmable and can so be adjusted to the external circuitry Overrun error detection is provided for the conversion result register ADDAT an interrupt request will be generated when the result of a previous conversion has not been re
85. up local subroutine register frames This enables subroutines to dynamically allocate local variables as needed within two machine cycles A local frame is allocated by simply subtracting the number of required local registers from the SP and then moving the value of the new SP to the CP Semiconductor Group 20 9 1998 05 01 SIEMENS System Programming C161RI This operation is supported through the SCXT switch context instruction with the addressing mode reg mem Using this instruction saves the old contents of the CP on the system stack and moves the value of the SP into CP see example below Each local register is then accessed as if it was a normal register Upon exit from the subroutine first the old CP must be restored by popping it from the stack and then the number of used local registers must be added to the SP to restore the allocated local space back to the system stack Note The system stack is growing downwards while the register bank is growing upwards Old Stack Area Newly Allocated Register Bank Old CP Contents pee New doo Stack Area Figure 20 2 Local Registers The software to provide the local register bank for the example above is very compact After entering the subroutine SUB SP 10D Free 5 words in the current system stack SCXT CP SP Set the new register bank pointer Before exiting the subroutine POP CP Restore the old register bank ADD SP 10D Release th
86. us 51 2 us Period 26ms 52 5ms 105 ms 210 ms 420 ms 840 ms 1 68s 3 36 s Semiconductor Group 10 5 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timer 3 in Gated Timer Mode Gated timer mode for the core timer T3 is selected by setting bit field T3M in register T3CON to 010p or 011g Bit T3M 0 T3CON 3 selects the active level of the gate input In gated timer mode the same options for the input frequency as for the timer mode are available However the input clock to the timer in this mode is gated by the external input pin T3IN Timer T3 External Input To enable this operation pin T3IN must be configured as input i e the corresponding direction control bit must contain 0 Txl CPU Clock gt Interrupt 4 f Up TxM TR Down TXUD TxOTL ero TxOUT 1 MUX TxOE TxEUD e EXOR l T3IN P3 6 TxUDE X23 T3EUD P3 4 T3OUT P3 3 RT Figure 10 4 Block Diagram of Core Timer T3 in Gated Timer Mode If T3M O 0 the timer is enabled when T3IN shows a low level A high level at this pin stops the timer If T3M 0 1 pin T3IN must have a high level in order to enable the timer In addition the timer can be turned on or off by software using bit T3R The timer will only run if T3R 1 and the gate is active It will stop if either T3R 0 or the gate is inactive Note A transition of the gate signal at pin T3IN does not ca
87. used to change the transfer direction RSC is cleared automatically after the repeated start condition has been generated The bus is released by clearing bit BUM in register ICCON This generates a stop condition on the bus Operation in Multimaster Mode If multimaster mode is selected via bitfield MOD in register ICCON the on chip IC module can operate concurrently as a bus master or as a slave The descriptions of these modes apply accordingly Multimaster mode implies that several masters are connected to the same bus As more than one master may try to claim the bus at a given time an arbitration is done on the SDA line When a master device detects a mismatch between the data bit to be sent and the actual level on the SDA bus line it looses the arbitration and automatically switches to slave mode leaving the other device as the remaining master This loss of arbitration is indicated by bit AL in register ICST which must be checked by the driver software when operating in multimaster mode Lost arbitration is also indicated when the software tries to claim the bus by setting bit BUM while the TC module is operating in slave mode indicated by bit BB 1 Bit AL must be cleared via software Semiconductor Group 17 6 1998 05 01 SIEMENS The I2C Bus Module C161RI Operation in Slave Mode If the on chip PC module shall be controlled via the I C bus by a remote master i e be a bus slave slave mode must be selected via
88. with the SSC Semiconductor Group 12 1 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI Slave Clock CPU Baud Rate Clock Clock Rune Master Clock d SCLK Shift Clock Receive Int Request Transmit Int Request SSC Control Block Error Int Request Status Control MTSR Pin Control 16 Bit Shift Register MRST Transmit Buffer Receive Buffer Register SSCTB Register SSCRB Internal Bus lt __intermaigus SS MCB01957 Figure 12 2 Synchronous Serial Channel SSC Block Diagram The operating mode of the serial channel SSC is controlled by its bit addressable control register SSCCON This register serves for two purposes during programming SSC disabled by SSCEN 0 it provides access to a set of control bits during operation SSC enabled by SSCEN 1 it provides access to a set of status flags Register SSCCON is shown below in each of the two modes Semiconductor Group 12 2 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI SSCCON FFB2 D9 SFR Reset Value 0000 15 14 13 12 1i 10 9 8 7 6 5 4 3 2 1 0 SSC SSC SSC SSC SSC SSC SSC SSC SSC SSC KA RAER RRR R SRE sco rw rw rw rw rw rw rw rw rw rw rw Bit Function Programming Mode SSCEN 0 SSCBM SSC Data Width Selection 0 Reserved Do not use this combination PE EE Transfer Data Width is 2
89. wm MTSR MRST First Last Bit N Transmit Data Bit Latch Data MCD01960 Shift Data Figure 12 3 Serial Clock Phase and Polarity Options Semiconductor Group 12 5 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI 12 1 Full Duplex Operation The different devices are connected through three lines The definition of these lines is always determined by the master The line connected to the master s data output pin MTSR is the transmit line the receive line is connected to its data input line MRST and the clock line is connected to pin SCLK Only the device selected for master operation generates and outputs the serial clock on pin SCLK All slaves receive this clock so their pin SCLK must be switched to input mode DP3 13 0 The output of the master s shift register is connected to the external transmit line which in turn is connected to the slaves shift register input The output of the slaves shift register is connected to the external receive line in order to enable the master to receive the data shifted out of the slave The external connections are hard wired the function and direction of these pins is determined by the master or slave operation of the individual device Note The shift direction shown in the figure applies for MSB first operation as well as for LSB first operation When initializing the devices in this configuration select one device for master operation SSCMS 1 all others must
90. x x rw rw rw rw rw rw rw rw Bit Function P1X y Port data register P1H or P1L bit y DP1L F104 82 ESFR Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DP1L DP1L DP1L DP1L DP1L DP1L DP1L DP1L 7 6 5 4 3 2 1 0 EU m DP1H F106 83 ESFR 8 7 6 5 4 3 2 1 DP1H 7 rw rw rw rw rw rw rw rw Bit Function DP1X y Port direction register DP1H or DP1L bit y DP1X y 0 Port line P1X y is an input high impedance DP1X y 1 Port line P1X y is an output Semiconductor Group 7 9 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Functions of PORT1 When a demultiplexed external bus is enabled PORT1 is used as address bus Note that demultiplexed bus modes use PORT1 as a 16 bit port Otherwise all 16 port lines can be used for general purpose IO During external accesses in demultiplexed bus modes PORT1 outputs the 16 bit intra segment address as an alternate output function During external accesses in multiplexed bus modes when no BUSCON register selects a demultiplexed bus mode PORT1 is not used and is available for general purpose IO Alternate Function P1H 7 A15 P1H 6 A14 P1H 5 A13 P1H 4 A12 PH P1H 3 A11 P1H 2 A10 P1H 1 A9 P1H 0 A8 PORTI P1L7 A7 P1L 6 A6 P1L 5 A5 P1L 4 A4 PIL P1L 3 A3 P1L 2 A2 P1L 1 A1 P1L 0 AO General Purpose 8 16 bit Input Output Demux Bus Figure 7 6 PORTI1 IO and
91. 000 to FFFE STKUN FE16 0B SFR Reset Value FC00 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 r r r r rw r Bit Function stkun Modifiable portion of register STKUN Specifies the upper limit of the internal system stack The Stack Underflow Trap entered when SP gt STKUN may be used in two different ways Fatal error indication treats the stack underflow as a system error through the associated trap service routine Automatic system stack refilling allows to use the system stack as a Stack Cache for a bigger external user stack In this case register STKUN should be initialized to a value which represents the desired highest Bottom of Stack address More details about the stack underflow trap service routine and virtual stack management are given in chapter System Programming Scope of Stack Limit Control The stack limit control realized by the register pair STKOV and STKUN detects cases where the stack pointer SP is moved outside the defined stack area either by ADD or SUB instructions or by PUSH or POP operations explicit or implicit i e CALL or RET instructions This control mechanism is not triggered i e no stack trap is generated when e the stack pointer SP is directly updated via MOV instructions e the limits of the stack area STKOV STKUN are changed so that SP is outside of the new limits Semiconductor Group 4 26 1998 05 01 SIEMENS The Central Processing Unit CPU C
92. 0000 MDL FEOE 07 CPU Multiply Divide Register Low Word 0000 CP FE10 08 CPU Context Pointer Register FC00 SP FE12 09 CPU System Stack Pointer Register FCOO STKOV FE14 0A CPU Stack Overflow Pointer Register FAOO STKUN FE16 0B CPU Stack Underflow Pointer Register FC00 ADDRSEL1 FE18 0C Address Select Register 1 0000 ADDRSEL2 FE1A OD Address Select Register 2 0000 ADDRSEL3 FE1C OE Address Select Register 3 0000 ADDRSEL4 FE1E OF Address Select Register 4 0000 T2 FE40 20 GPT1 Timer 2 Register 00004 T3 FE42 21 GPT1 Timer 3 Register 00004 T4 FE44 224 GPT1 Timer 4 Register 0000 T5 FE46 23 GPT2 Timer 5 Register 0000 T6 FE48 24 GPT2 Timer 6 Register 00004 CAPREL FE4A 25 GPT2 Capture Reload Register 0000 ADDAT FEAO 50 A D Converter Result Register 0000 WDT FEAE 57 Watchdog Timer Register read only 0000 SOTBUF FEBO 584 Serial Channel 0 Transmit Buffer Register 00004 Semiconductor Group 21 10 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value SORBUF FEB2 59 Serial Channel 0 Receive Buffer Register XXXX read only SOBG FEBA 5A Serial Channel 0 Baud Rate Generator Reload 0000 Register PECCO FECO 60 PEC Channel 0 Control Register 0000 PECC1 FEC2 61 PEC Channel 1 Control Register 0000 PECC2 FEC
93. 1 and N 2 are executed out of external memory instructions N 1 and N require external operand read accesses instructions N 3 through N write back external operands and the interrupt vector also points to an external location In this case the interrupt response time is the time to perform 9 word bus accesses because instruction 11 cannot be fetched via the external bus until all write fetch and read requests of preceding instructions in the pipeline are terminated When the above example has the interrupt vector pointing into the internal code memory the interrupt response time is 7 word bus accesses plus 2 states because fetching of instruction 11 from internal code memory can start earlier When instructions N N 1 and N 2 are executed out of external memory and the interrupt vector also points to an external location but all operands for instructions N 3 through N are in internal memory then the interrupt response time is the time to perform 3 word bus accesses When the above example has the interrupt vector pointing into the internal code memory the interrupt response time is 1 word bus access plus 4 states After an interrupt service routine has been terminated by executing the RETI instruction and if further interrupts are pending the next interrupt service routine will not be entered until at least two instruction cycles have been executed of the program that was interrupted In most cases two instructions will be execut
94. 14 13 12 11 10 9 8 7 6 T6IR T6IE ILVL GLVL CRIC FF6A B5 SFR Reset Value 00 xd a eee i e MU hs cere ud 6 CRIR CRIE ILVL GLVL rw Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Semiconductor Group 10 29 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI 11 The Asynchronous Synchronous Serial Interface The Asynchronous Synchronous Serial Interface ASCO provides serial communication between the C161RI and other microcontrollers microprocessors or external peripherals The ASCO supports full duplex asynchronous communication up to 500 KBaud and half duplex synchronous communication up to 2 MBaud 16 MHz CPU clock In synchronous mode data are transmitted or received synchronous to a shift clock which is generated by the C161RI In asynchronous mode 8 or 9 bit data transfer parity generation and the number of stop bits can be selected Parity framing and overrun error detection is provided to increase the reliability of data transfers Transmission and reception of data is double buffered For multiprocessor communication a mechanism to distinguish address from data bytes is included Testing is supported by a loop back option A 13 bit baud rate generator provides the ASCO with a separate serial clock signal Ports amp Direction Control Data Registers Control Registers Interrupt Control Alternate Func
95. 161RI The Multiply Divide High Register MDH This register is a part of the 32 bit multiply divide register which is implicitly used by the CPU when it performs a multiplication or a division After a multiplication this non bit addressable register represents the high order 16 bits of the 32 bit result For long divisions the MDH register must be loaded with the high order 16 bits of the 32 bit dividend before the division is started After any division register MDH represents the 16 bit remainder MDH FEOC 06 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 d 0 rw Bit Function mdh Specifies the high order 16 bits of the 32 bit multiply and divide register MD Whenever this register is updated via software the Multiply Divide Register In Use MDRIU flag in the Multiply Divide Control register MDC is set to 1 When a multiplication or division is interrupted before its completion and when a new multiply or divide operation is to be performed within the interrupt service routine register MDH must be saved along with registers MDL and MDC to avoid erroneous results A detailed description of how to use the MDH register for programming multiply and divide algorithms can be found in chapter System Programming The Multiply Divide Low Register MDL This register is a part of the 32 bit multiply divide register which is implicitly used by the CPU when it performs a multiplication or a div
96. 2 7 x x x x 9 sources on 3 levels 6 X 5 X X X X Interrupt Class 3 4 X 5 sources on 2 levels 3 2 1 0 No service 5 4 Saving the Status during Interrupt Service Before an interrupt request that has been arbitrated is actually serviced the status of the current task is automatically saved on the system stack The CPU status PSW is saved along with the location where the execution of the interrupted task is to be resumed after returning from the service routine This return location is specified through the Instruction Pointer IP and in case of a segmented memory model the Code Segment Pointer CSP Bit SGTDIS in register SYSCON controls how the return location is stored The system stack receives the PSW first followed by the IP unsegmented or followed by CSP and then IP Segmented mode This optimizes the usage of the system stack if segmentation is disabled The CPU priority field ILVL in PSW is updated with the priority of the interrupt request that is to be serviced so the CPU now executes on the new level If a multiplication or division was in progress at the time the interrupt request was acknowledged bit MULIP in register PSW is set to 1 In this case the return location that is saved on the stack is not the next instruction in the instruction flow but rather the multiply or divide instruction itself as this instruction has been interrupted and will be completed after retu
97. 2 79 RSTOUT P5 14 T4EUD L 3 78 _ RSTN P5 15 T2EUD 4 77 O Voo Vss U 5 76 Vss XTAL1 L 6 75 P1H 7 A15 XTAL2 L 7 74 P1H 6 A14 73 P1H 5 A13 72 P1H 4 A12 71 Ll P1H 3 A11 70 P1H 2 A10 P3 0 SCLO L 9 P3 1 SDAO 10 P3 2 CAPIN 11 P3 3 T30UT 12 eo P1H 1 A9 P3 4 T3EUD 13 68 P1H o A8 P3 5 T4IN 14 C161RI 67 L1 Voo P3 6 T3IN 15 P3 7 T2IN L 16 P3 8 MRST 17 P3 9 MTSR 18 P3 10 TxDo C 19 P3 11 RxDO J 20 P3 12 BHE WRH 21 P3 13 SCLK 22 59 P1L 1 A1 P3 15 CLKOUT 23 58 P1L 0 A0 Vss L 24 57 POH 7 AD15 56 _ POH 6 AD14 55 POH 5 AD13 54 POH 4 AD12 53 POH 3 AD11 52 POH 2 AD10 65 P1L 7 A7 64 _ P1L 6 A6 63 P1L 5 A5 62 P1L 4 A4 61 L P1L 3 A3 60 P1L 2 A2 P4 0 A16 26 P4 1 A17 27 P4 2 A18 28 P4 3 A19 29 P4 4 A20 L 30 e 1 0 OR 0 Oo oo 51 L POH 1 AD9 e e C co C C t OWN E Ww 9 QO QNcOstiodor 2H aiken 9000000 Yoo lt a Ele lt lt lt eccce lt lt i ES Li O X Q oO x 10 ON o o ioc y Sy Sh a I oa E Ooooooooo o ooaaanaaana a Figure 23 1 Pin Description for C161RI P MQFP 100 Package Semiconductor Group 23 2 1998 05 01 SIEMENS Device Specification C161RI N N N N N N ZZN KOON 22z2 kxzooBbBBRE E X X X oLD FSAA AOLO z NAO Goat norit m mper Tar a E
98. 3 2 1 0 rw rw rw rw rw rw rw Bit Function P4 y Port data register P4 bit y DP4 FFCA E5 SFR Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppasjpasjopaalppaalopa zippa bao w w w w w w IW Bit Function DP4 y Port direction register DP4 bit y DP4 y 0 Port line P4 y is an input high impedance DP4 y 1 Port line P4 y is an output Alternate Functions of Port 4 During external bus cycles that use segmentation i e an address space above 64 KByte a number of Port 4 pins may output the segment address lines The number of pins that is used for segment address output determines the external address space which is directly accessible The other pins of Port 4 if any may be used for general purpose IO If segment address lines are selected the alternate function of Port 4 may be necessary to access e g external memory directly after reset For this reason Port 4 will be switched to this alternate function automatically The number of segment address lines is selected via PORTO during reset The selected value can be read from bitfield SALSEL in register RPOH read only e g in order to check the configuration during run time Semiconductor Group 7 20 1998 05 01 SIEMENS Parallel Ports C161RI The table below summarizes the alternate functions of Port 4 depending on the number of selected segment address lines coded via bitfield SALSEL Port
99. 4 CA External Interrupt 6 Control Register 0000 CC15IC b FF96 CB External Interrupt 7 Control Register 0000 ADCIC b FF98 CC A D Converter End of Conversion Interrupt 0000 Control Register ADEIC b FF9A CD A D Converter Overrun Error Interrupt Control 0000 Register ADCON b FFAO0 DO A D Converter Control Register 0000 P5 b FFA2 D1 Port 5 Register read only XXXXy P5DIDIS b FFA4 D24 Port 5 Digital Input Disable Register 00004 TFR b FFAC D6 Trap Flag Register 0000 WDTCON b FFAE D7 Watchdog Timer Control Register 00Xx SOCON b FFBO D8 Serial Channel 0 Control Register 0000 SSCCON b FFB2 D9 SSC Control Register 0000 P2 b FFCO EO Port 2 Register 0000 DP2 b FFC2 E1 Port 2 Direction Control Register 0000 P3 b FFC4 E24 Port 3 Register 0000 Semiconductor Group 21 12 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value DP3 b FFC6 E3 Port 3 Direction Control Register 0000 P4 b FFC8 E4 Port 4 Register 8 bits 00 DP4 b FFCA E5 Port 4 Direction Control Register 00 P6 b FFCC E64 Port 6 Register 8 bits 00 DP6 b FFCE E7 Port 6 Direction Control Register 00 The system configuration is selected during reset 2 The reset value depends on the indicated reset source Semiconductor Group 21 13 1998 05 01 SIEMENS The Register Set C161RI 21 5 Special Notes PEC Pointer R
100. 4g Fast External Interrupt 1 CC9IR CC9IE CC9INT 00 0064 19 25 Fast External Interrupt 2 CC10IR CC10IE CC10INT 00 0068 1A4 265 Fast External Interrupt 3 CC11IR CC11IE CC11INT 00 006C 1B4 275 Fast External Interrupt 4 CC12lR CC12lIE CC12INT 00 0070 1C 285 Fast External Interrupt 5 CC13IR CC13IE CC13INT 00 0074 1D 295 Fast External Interrupt 6 CC14IR CC14IE CC14INT 00 0078 1E4 30 Fast External Interrupt 7 CC15IR CC15IE CC15INT 00 007C 1F4 31p GPT1 Timer 2 T2IR T2lE T2INT 00 0088 22 345 GPT1 Timer 3 T3IR TSIE TSINT 00 008C 234 35p GPT1 Timer 4 T4IR T4lE T4INT 00 0090 24 365 GPT2 Timer 5 T5IR T5IE T5INT 00 0094 25 4 375 GPT2 Timer 6 T6IR T6IE T6INT 00 0098 26 38p GPT2 CAPREL Register CRIR CRIE CRINT 00 009C 27 395 A D Conversion Complete ADCIR ADCIE ADCINT 00 00A0 28 40 gt A D Overrun Error ADEIR ADEIE ADEINT 00 00A4 29 415 ASCO Transmit SOTIR SOTIE SOTINT 00 00A8 2A 425 ASCO Transmit Buffer SOTBIR SOTBIE SOTBINT 00 011C 474 Tlp ASCO Receive SORIR SORIE SORINT 00 00AC 2B 435 ASCO Error SOEIR SOEIE SOEINT 00 00B0 2C 445 SSC Transmit SCTIR SCTIE SCTINT 00 00BA 2D 45p SSC Receive SCRIR SCRIE SCRINT 00 00B8 2E 465 SSC Error SCEIR SCEIE SCEINT 00 00BC 2F4 47p FC Data Transfer Event XPOIR XPOIE XPOINT 00 0100 40 64 PC Protocol Event XP1IR XP1IE XP1INT 00 0104 414 65g X Peripheral Node 2 XP2IR XP2IE XP2INT 00 0108 42 665 RTC via ISNC XPSIR XP3IE
101. 5 01 SIEMENS Architectural Overview C161RI Saving of system state is automatically performed on the internal system stack avoiding the use of instructions to preserve state upon entry and exit of interrupt or trap routines Call instructions push the value of the IP on the system stack and require the same execution time as branch instructions Instructions have also been provided to support indirect branch and call instructions This supports implementation of multiple CASE statement branching in assembler macros and high level languages Consistent and Optimized Instruction Formats To obtain optimum performance in a pipelined design an instruction set has been designed which incorporates concepts from Reduced Instruction Set Computing RISC These concepts primarily allow fast decoding of the instructions and operands while reducing pipeline holds These concepts however do not preclude the use of complex instructions which are required by microcontroller users The following goals were used to design the instruction set 1 Provide powerful instructions to perform operations which currently require sequences of instructions and are frequently used Avoid transfer into and out of temporary registers such as accumulators and carry bits Perform tasks in parallel such as saving state upon entry into interrupt routines or subroutines 2 Avoid complex encoding schemes by placing operands in consistent fields for each instruc tion Als
102. 5 3 ADCIC A D Converter Interrupt Control Register P5DIDIS Port 5 Digital Input Disable Register End of Conversion ADDAT A D Converter Result Register ADEIC A D Converter Interrupt Control Register ADCON A D Converter Control Register Overrun Error Figure 16 1 SFRs and Port Pins associated with the A D Converter Semiconductor Group 16 1 1998 05 01 SIEMENS The Analog Digital Converter C161RI The external analog reference voltages Varer and Vagnp are fixed The separate supply for the ADC reduces the interference with other digital signals The conversion time is programmable so the ADC can be adjusted to the internal resistances of the analog sources and or the analog reference voltage supply ADCON Conversion Control Interrupt Requests AN3 P5 3 MUX Bi Result Reg ADDAT Converter ANO P5 0 VAREF V AGND Figure 16 2 Analog Digital Converter Block Diagram Semiconductor Group 16 2 1998 05 01 SIEMENS The Analog Digital Converter C161RI 16 1 Mode Selection and Operation The analog input channels ANO ANG are alternate functions of Port 5 which is an input only port The Port 5 lines may either be used as analog or digital inputs For pins that shall be used as analog inputs it is recommended to disable the digital input stage via register P5DIDIS This avoids undesired cross currents and switching noise while the analog input signal level is between Vj and V
103. A 62 PEC Channel 2 Control Register 0000 PECC3 FEC6 63 PEC Channel 3 Control Register 0000 PECCA FEC8 64 PEC Channel 4 Control Register 0000 PECC5 FECA 165 PEC Channel 5 Control Register 0000 PECC6 FECC 166 PEC Channel 6 Control Register 0000 PECC7 FECE 67 PEC Channel 7 Control Register 0000 POL b FFOO 80 Port 0 Low Register Lower half of PORTO 00 POH b FF02 81 Port 0 High Register Upper half of PORTO 00 P1L b FF04 82 Port 1 Low Register Lower half of PORT1 00 P1H b FFO6 83 Port 1 High Register Upper half of PORT1 00 BUSCONO b FFOC 86 Bus Configuration Register 0 0000 MDC b FFOE 87 CPU Multiply Divide Control Register 0000 PSW b FF10 88 CPU Program Status Word 0000 SYSCON b FF12 89 CPU System Configuration Register 0XX0 BUSCON1 b FF14 8A Bus Configuration Register 1 0000 BUSCON b FF16 8B Bus Configuration Register 2 0000 BUSCONGS b FF18 8C Bus Configuration Register 3 0000 BUSCON4 b FF1A 8D Bus Configuration Register 4 0000 ZEROS b FF1C 8E Constant Value 0 s Register read only 0000 ONES b FF1E 8F Constant Value 1 s Register read only FFFF T2CON b FF40 A0 GPT1 Timer 2 Control Register 0000 T3CON b FF42 Aly GPT1 Timer 3 Control Register 0000 T4CON b FF44 A2 GPT1 Timer 4 Control Register 0000 T5CON b FF46 A3 GPT2 Timer 5 Control Register 0000 T6CON b FF48 A4 GPT2 Timer 6 Control Register 0000 T2lC b FF60 B0 GPT1 Time
104. Alternate Functions When an external bus mode is enabled the direction of the port pin and the loading of data into the port output latch are controlled by the bus controller hardware The input of the port output latch is disconnected from the internal bus and is switched to the line labeled Alternate Data Output via a multiplexer The alternate data is the 16 bit intrasegment address While an external bus mode is enabled the user software should not write to the port output latch otherwise unpredictable results may occur When the external bus modes are disabled the contents of the direction register last written by the user becomes active Semiconductor Group 7 10 1998 05 01 SIEMENS Parallel Ports C161RI The figure below shows the structure of a PORTI pin Write DP1H y DP1L y Direction Latch Read DP1H y DP1L y I Alternate B Function e t Enable e r n Write P1H y P1L y Alternate a Data 1 Output MUX P1H y Port Output slo Output PiLy B Latch Buffer u Read P1H y P1L y Alternate y 7 0 MCB03896 Figure 7 7 Block Diagram of a PORT1 Pin Semiconductor Group 7 11 1998 05 01 SIEMENS Parallel Ports C161RI 7 3 Port2 If this 8 bit port is used for general purpose IO the direction of each line can be configured via the corresponding direction register DP2 Each port line can be switched into push pull or open drain
105. BUS peripherals are disabled 1 XBUS peripherals are accessible via the external bus during hold mode VISIBLE Visible Mode Control 0 Accesses to XBUS peripherals are done internally 1 XBUS peripheral accesses are made visible on the external pins Semiconductor Group 4 11 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Bit Function XPEN XBUS Peripheral Enable Bit 0 Accesses to the on chip X Peripherals and their functions are disabled 1 The on chip X Peripherals are enabled and can be accessed BDRSTEN Bidirectional Reset Enable Bit 0 Pin RSTIN is an input only 1 Pin RSTIN is pulled low during the internal reset sequence OWDDIS Oscillator Watchdog Disable Bit 0 The on chip oscillator watchdog is enabled and active 1 The on chip oscillator watchdog is disabled and the CPU clock is always fed from the oscillator input CSCFG Chip Select Configuration Control 0 Latched CS mode The CS signals are latched internally and driven to the enabled port pins synchronously 1 Unlatched CS mode The CS signals are directly derived from the address and driven to the enabled port pins WRCFG Write Configuration Control Set according to pin POH O during reset 0 Pins WR and BHE retain their normal function 1 Pin WR acts as WRL pin BHE acts as WRH CLKEN System Clock Output Enable CLKOUT 0 CLKOUT disabled pin may be used for general purpose IO 1 CLKOUT enabled pin
106. BUSCONO Semiconductor Group 9 1 1998 06 01 SIEMENS The External Bus Interface C161RI Single Chip Mode Single chip mode is entered when pin EA is high during reset In this case register BUSCONO is initialized with 0000 which also resets bit BUSACTO so no external bus is enabled In single chip mode the C161RI operates only with and out of internal resources No external bus is configured and no external peripherals and or memory can be accessed Also no port lines are occupied for the bus interface When running in single chip mode however external access may be enabled by configuring an external bus under software control Single chip mode allows the C161RI to start execution out of the internal program memory Mask ROM OTP or Flash memory Note Any attempt to access a location in the external memory space in single chip mode results in the hardware trap ILLBUS 9 1 External Bus Modes When the external bus interface is enabled bit BUSACTx 1 and configured bitfield BTYP the C161RI uses a subset of its port lines together with some control lines to build the external bus BTYP Encoding External Data Bus Width External Address Bus Mode 00 8 bit Data Demultiplexed Addresses 0 1 8 bit Data Multiplexed Addresses 10 16 bit Data Demultiplexed Addresses 11 16 bit Data Multiplexed Addresses The bus configuration BTYP for the address windows BUSCON4 BUSCON 1 is selected via software t
107. C04 It uses 7 bit addressing with a slave address of 50 which is concatenated with the Read Write bit This program does not use interrupts but polls the corresponding IC interrupt request flags The master C161RI starts in master transmitter mode and first sends the slave address A0 50 0g followed by the subaddress 00 The C161RI changes to master receiver mode repeats the slave address A1 50 1 and then receives two bytes The first byte is acknowledged ACK 0 by the master the second byte is not acknowledged ACK 1 The transfer is finished with a STOP condition by the master The following figure shows the waveforms for the described transfer A programming example in C illustrates how the operation could be realized Legend SDA Data line SCL Clock line ST Start condition a SP Stop m i A condition Master Transmitter Master Receiver RS Repeated Start cond ACK Acknow ledge NACK No acknow Master Receiver Figure 17 5 EFC Bus Programming Example Waveforms Semiconductor Group 17 13 1998 05 01 SIEMENS The PC Bus Module C161RI ji em M eee eee ETT MISTER N Programming example to read 2 bytes from an NVRAM via the I2C bus je void main X peripheral enable SYSCON 0x0004 set XPEN before EINIT instr I2C control register configura
108. CALLS call inter segment subroutine instruction This instruction preserves both the CSP code segment pointer and IP on the system stack Upon return from the subroutine a RETS return from inter segment subroutine instruction must be used to restore both the CSP and IP This ensures that the next instruction after the CALLS instruction is fetched from the correct segment Note lt is possible to use CALLS within the same segment but still two words of the stack are used to store both the IP and CSP Providing Local Registers for Subroutines For subroutines which require local storage the following methods are provided Alternate Bank of Registers Upon entry into a subroutine it is possible to specify a new set of local registers by executing the SCXT switch context instruction This mechanism does not provide a method to recursively call a subroutine Saving and Restoring of Registers To provide local registers the contents of the registers which are required for use by the subroutine can be pushed onto the stack and the previous values be popped before returning to the calling routine This is the most common technique used today and it does provide a mechanism to support recursive procedures This method however requires two machine cycles per register stored on the system stack one cycle to PUSH the register and one to POP the register Use of the System Stack for Local Registers It is possible to use the SP and CP to set
109. CAPREL Semiconductor Group 10 28 1998 05 01 SIEMENS The General Purpose Timer Units C161RI to perform a reload on underflow This means the value in register CAPREL represents the time between two underflows of timer T6 now measured in timer T6 increments Since timer T6 runs 8 times faster than timer T5 it will underflow 8 times within the time between two external events Thus the underflow signal of timer T6 generates 8 ticks Upon each underflow the interrupt request flag T6IR will be set and bit T6OTL will be toggled Interrupt Control for GPT2 Timers and CAPREL When a timer overflows from FFFF to 0000 when counting up or when it underflows from 0000 to FFFF when counting down its interrupt request flag T5IR or T6IR in register TxIC will be set Whenever a transition according to the selection in bit field Cl is detected at pin CAPIN interrupt request flag CRIR in register CRIC is set Setting any request flag will cause an interrupt to the respective timer or CAPREL interrupt vector T5INT T6INT or CRINT or trigger a PEC service if the respective interrupt enable bit T5IE or T6IE in register TxIC CRIE in register CRIC is set There is an interrupt control register for each of the two timers and for the CAPREL register T5IC FF66 B3 SFR Reset Value 00 9 414 9 cde cll Do ree s c 5 4 3 2 1 0 6 T5IR T5IE ILVL GLVL rw rw rw T6IC FF68 B4 SFR Reset Value 00 15
110. CCx FECy 62 see table SFR Reset Value 0000 15 14 11 7 6 5 4 3 2 1 0 13 12 10 9 8 rw rw rw Bit Function COUNT PEC Transfer Count Counts PEC transfers and influences the channel s action see table below BWT Byte Word Transfer Selection 0 Transfer a Word 1 Transfer a Byte INC Increment Control Modification of SRCPx or DSTPx 0 0 Pointers are not modified 0 1 Increment DSTPx by 1 or 2 BWT 1 0 Increment SRCPx by 1 or 2 BWT 1 1 Reserved Do not use this combination changed to 10 by hardware PEC Control Register Addresses Register Address Reg Space Register Address Reg Space PECCO FECO 60 SFR PECC4 FEC8 644 SFR PECC1 FEC2 61 SFR PECC5 FECA 65 SFR PECC2 FEC4 62 SFR PECC6 FECC 664 SFR PECC3 FEC6 63 SFR PECC7 FECE 67 SFR Byte Word Transfer bit BWT controls if a byte or a word is moved during a PEC service cycle This selection controls the transferred data size and the increment step for the modified pointer Semiconductor Group 1998 05 01 Interrupt and Trap Functions C161RI SIEMENS Increment Control Field INC controls if one of the PEC pointers is incremented after the PEC transfer It is not possible to increment both pointers however If the pointers are not modified INC 005 the respective channel will always move data from the same source to the same destination Note The
111. CPU branches to the trap vector location for the respective trap condition Depending on the trap condition the instruction which caused the trap is either completed or cancelled i e it has no effect on the system state before the trap handling routine is entered Hardware traps are non maskable and always have priority over every other CPU activity If several hardware trap conditions are detected within the same instruction cycle the highest priority trap is serviced see table in section Interrupt System Structure PSW CSP in segmentation mode and IP are pushed on the internal system stack and the CPU level in register PSW is set to the highest possible priority level i e level 15 disabling all interrupts The CSP is set to code segment zero if segmentation is enabled A trap service routine must be terminated with the RETI instruction Semiconductor Group 5 24 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI The eight hardware trap functions of the C161RI are divided into two classes Class A traps are e external Non Maskable Interrupt NMI Stack Overflow Stack Underflow trap These traps share the same trap priority but have an individual vector address Class B traps are Undefined Opcode Protection Fault Illegal Word Operand Access Illegal Instruction Access Illegal External Bus Access Trap These traps share the same trap priority and the same vector address The bit addressabl
112. Components used in life support devices or systems must be expressly authorized for such purpose Critical components of the Semiconductor Group of Siemens AG may only be used in life support devices or systems with the ex press written approval of the Semiconductor Group of Siemens AG 1 Acritical component is a component used in a life support device or system whose failure can reasonably be expected to cause the failure of that life support de vice or system or to affect its safety or ef fectiveness of that device or system 2 Life support devices or systems are in tended a to be implanted in the human body or b to support and or maintain and sustain human life If they fail it is reasonable to assume that the health of the user may be endangered C161RI Revision History Version 1 0 05 98 Previous Releases Page Subjects We Listen to Your Comments Any information within this document that you feel is wrong unclear or missing at all Your feedback will help us to continuously improve the quality of this document Please send your proposal including a reference to this document to mcdocu comments siemens scg com bx SIEMENS G16 1R General Information Table of Contents Page 1 introduction Duos Eo ERE RARE SE RRE DEEA POTERAT NAT S 1 1 1 1 The Members of the 16 bit Microcontroller Family 22000 eee 1 2 1 2 Summary or Basic Features i5 ese tee
113. DCIC is set This end of conversion interrupt request may cause an interrupt to vector ADCINT or it may trigger a PEC data transfer which reads the conversion result from register ADDAT e g to store it into a table in the internal RAM for later evaluation The interrupt request flag ADEIR in register ADEIC will be set if a conversion result overwrites a previous value in register ADDAT error interrupt in standard mode This interrupt request may be used to cause an interrupt to vector ADEINT ADCIC FF98 CC SFR Reset Value 00 Ee A a U A NEUEN EE NT NE Re RENE mw rw rw rw ADEIC FF9A CD SFR Reset Value 00 Ui e du Lue P educ eet E Ph idu decr anb D 6 mw rw rw rw Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Semiconductor Group 16 6 1998 05 01 2 SIEMENS The I2C Bus Module C161RI 17 The PC Bus Module The on chip I C bus module Inter Integrated Circuit connects the C161RI to other external controllers and or peripherals via the two line serial PC interface The I C Bus module provides communication at data rates of up to 400 Kbit s in master and or slave mode and features 7 bit addressing as well as 10 bit addressing Note The I C Bus module is an XBUS peripheral and therefore requires bit XPEN in register SYSCON to be set in order to be operable Core Registers Control Registers Data Register
114. During emulation mode pin RSTOUT is used as an input and therefore must be driven by the external circuitry The Power Supply pins for the Analog Digital Converter VAREF and VAGND provide a separate power supply for the on chip ADC This reduces the noise that is coupled to the analog input signals from the digital logic sections and so improves the stability of the conversion results when VAREF and VAGND are properly discoupled from VDD and VSS The Power Supply pins VDD and VSS provide the power supply for the digital logic of the C161RI The respective VDD VSS pairs should be decoupled as close to the pins as possible For best results it is recommended to implement two level decoupling e g the widely used 100 nF in parallel with 30 40 pF capacitors which deliver the peak currents Note All VDD pins and all VSS pins must be connected to the power supply and ground respectively Semiconductor Group 8 3 1998 05 01 SIEMENS The External Bus Interface C161RI 9 The External Bus Interface Although the C161RI provides a powerful set of on chip peripherals and on chip RAM and ROM OTP Flash except for ROMless versions areas these internal units only cover a small fraction of its address space of up to 16 MByte The external bus interface allows to access external peripherals and additional volatile and non volatile memory The external bus interface provides a number of configurations so it can be taylored to fit perfectly into a
115. EDO06 X FC Address Register OXXX ICCFG EDOO X FC Configuration Register XX00 ICCON EDO2 X FC Control Register 0000 ICRTB EDO8 X FC Receive Transmit Buffer XX ICST EDOA X FC Status Register 0000 IDCHIP F07C E 3E Identifier 09XX IDMANUF F07E E 3F Identifier 1820 IDMEM F07A E 3D Identifier 00004 IDPROG F078 E 3C Identifier 00004 ISNC b F1DE E EF Interrupt Subnode Control Register 0000 MDC b FFOE 87 CPU Multiply Divide Control Register 0000 MDH FEOC 06 CPU Multiply Divide Register High Word 0000 MDL FEOE 07 CPU Multiply Divide Register Low Word 00004 ODP2 b F1C2 E E14 Port 2 Open Drain Control Register 0000 ODP3 b F1C6 E E3 Port 3 Open Drain Control Register 0000 ODP6 b FICE E E7 Port 6 Open Drain Control Register 00 ONES b FF1E 8F Constant Value 1 s Register read only FFFF POL b FFOO 80 Port 0 Low Register Lower half of PORTO 00 POH b FF02 814 Port 0 High Register Upper half of PORTO 00 P1L b FF04 82 Port 1 Low Register Lower half of PORT1 00 Semiconductor Group 21 5 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value P1H b FFO6 83 Port 1 High Register Upper half of PORT1 00 P2 b FFCO EO Port 2 Register 0000 P3 b FFC4 E24 Port 3 Register 0000 P4 b FFC8 E44 Port 4 Regi
116. ENS General Purpose Registers The General Purpose Registers GPRs use a block of 16 consecutive words within the internal RAM The Context Pointer CP register determines the base address of the currently active register bank This register bank may consist of up to 16 word GPRs RO R1 R15 and or of up to 16 byte GPRs RLO RHO RL7 RH7 The sixteen byte GPRs are mapped onto the first eight word GPRs see table below In contrast to the system stack a register bank grows from lower towards higher address locations and occupies a maximum space of 32 Byte The GPRs are accessed via short 2 4 or 8 bit addressing modes using the Context Pointer CP register as base address independent of the current DPP register contents Additionally each bit in the currently active register bank can be accessed individually Mapping of General Purpose Registers to RAM Addresses Internal RAM Address Byte Registers Word Register CP 1E Ha R15 CP 1C R14 CP 1A R13 CP 18 R12 lt CP gt 164 R11 lt CP gt 144 R10 CP 124 R9 CP 10 H8 CP OE RH7 RL7 R7 CP 0C RH6 RL6 R6 CP 0A RH5 RL5 R5 CP 08 RH4 RL4 R4 CP 06 RH3 RL3 R3 CP 04 RH2 RL2 R2 CP 02 RH1 RL1 R1 CP 00 RHO RLO RO The C161RI supports fast register bank context switching Multiple register
117. ENS Parallel Ports C161RI There is one basic structure for all port lines with only an alternate input function Port lines with only an alternate output function however have different structures due to the way the direction of the pin is switched and depending on whether the pin is accessible by the user software or not in the alternate function mode All port lines that are not used for these alternate functions may be used as general purpose IO lines When using port pins for general purpose output the initial output value should be written to the port latch prior to enabling the output drivers in order to avoid undesired transitions on the output pins This applies to single pins as well as to pin groups see examples below OUTPUT ENABLE SINGLE PIN BSET P4 0 Initial output level is high BSET DP4 0 Switch on the output driver OUTPUT ENABLE PIN GROUP BFLDL P4 05H 05H PInitial output level is high BFLDL DP4 05H 05H Switch on the output drivers Note When using several BSET pairs to control more pins of one port these pairs must be separated by instructions which do not reference the respective port see Particular Pipeline Effects in chapter The Central Processing Unit Each of these ports and the alternate input and output functions are described in detail in the following subsections Semiconductor Group 7 5 1998 05 01 SIEMENS Parallel Ports C161RI 7 1 PORTO The two 8 bit ports POH
118. ENS Power Management C161RI Reset XX V State transition when writing xx to CLKCON Figure 19 4 Clock Switching State Machine Clock Switching State Description State fcpy CLK Note Number Source CON 1 Basic 00 Standard operation on basic clock frequency 2 SDD 01 SDD operation Manual switch back to basic clock frequency Semiconductor Group 19 9 1998 05 01 SIEMENS Power Management C161RI 19 4 Flexible Peripheral Management The power consumed by the C161RI also depends on the amount of active logic Peripheral management enables the system designer to deactivate those on chip peripherals that are not required in a given system status e g a certain interface mode or standby All modules that remain active however will still deliver their usual performance If all modules that are fed by the peripheral clock driver PCD are disabled and also the other functions fed by the PCD are not required this clock driver itself may also be disabled to save additional power This flexibility is realized by distributing the CPU clock via several clock drivers which can be separately controlled and may also be smaller Idle mode Clock Generation CPU PCDDIS Peripherals Ports Intr Ctrl Interface Peripherals Figure 19 5 CPU Clock Distribution Note The Real Time Clock RTC is fed by a separate clock driver so it can be kept running even i
119. Extended SFR Space ESFRs are marked with the letter E in column Physical Address Registers within on chip X Peripherals are marked with the letter X in column Physical Address Name Physical 8 Bit Description Reset Address Address Value ADCIC b FF98 CC A D Converter End of Conversion Interrupt 0000 Control Register ADCON b FFAO0 DO A D Converter Control Register 0000 ADDAT FEAO 50 A D Converter Result Register 0000 ADDRSEL1 FE18 0C Address Select Register 1 0000 ADDRSEL2 FE1A OD Address Select Register 2 00004 ADDRSEL3 FE1C OE Address Select Register 3 0000 ADDRSEL4 FE1E OF Address Select Register 4 0000 ADEIC b FF9A CDy A D Converter Overrun Error Interrupt Control 0000 Register BUSCONO bi FFOC 86 Bus Configuration Register 0 0000 BUSCON1 bi FF14 8A Bus Configuration Register 1 0000 BUSCON b FF16 8B Bus Configuration Register 2 0000 BUSCONGS b FF18 8C Bus Configuration Register 3 0000 BUSCONA b FF1A 8D Bus Configuration Register 4 0000 CAPREL FE4A 25 GPT2 Capture Reload Register 0000 CC8IC b FF88 C4 External Interrupt 0 Control Register 0000 CC9IC b FF8A C5 External Interrupt 1 Control Register 0000 CC10IC b FF8C C6 External Interrupt 2 Control Register 0000 CC11IC b FF8E C7 External Interrupt 3 Control Register 0000 CC121C b FF90 C8 External Inter
120. I Internal RAM R15 R14 R13 R12 R11 R10 CP 30 CP 28 Context Pointer ZB JJ I MCD02003 Figure 4 7 Register Bank Selection via Register CP Several addressing modes use register CP implicitly for address calculations The addressing modes mentioned below are described in chapter Instruction Set Summary Short 4 Bit GPR Addresses mnemonic Rw or Rb specify an address relative to the memory location specified by the contents of the CP register i e the base of the current register bank Depending on whether a relative word Rw or byte Rb GPR address is specified the short 4 bit GPR address is either multiplied by two or not before it is added to the content of register CP see figure below Thus both byte and word GPR accesses are possible in this way GPRs used as indirect address pointers are always accessed wordwise For some instructions only the first four GPRs can be used as indirect address pointers These GPRs are specified via short 2 bit GPR addresses The respective physical address calculation is identical to that for the short 4 bit GPR addresses Short 8 Bit Register Addresses mnemonic reg or bitoff within a range from FO to FF interpret the four least significant bits as short 4 bit GPR address while the four most significant bits are ignored The respective physical GPR address calculation is identical to that for the short 4 bit GPR addresses For single bit
121. IEMENS System Programming C161RI FBFE 1111 1011 1111 1110 FBFE 1111 1011 11111110 FB80 1 1 1 1 1011 1000 0000 Phys A FAO0 1 1 1 1 1010 0000 0000 reso 1111 1011 1000 0000 lt sp gt Feoo 1111 1000 0000 0000 After PUSH After PUSH FBFE 1111 1011 1111 1110 FBFE 1 1 1 1 101 ands i ve bts FBFE 11111011 11111110 Phys A FBFE Q111 1011 11111110 FB7E 11111011 01111110 lt SP gt F FE o 1111 1110 64 words Stack Size 256 words Figure 20 1 Physical Stack Address Generation The following example demonstrates the circular stack mechanism which is also an effect of this virtual stack mapping First register R1 is pushed onto the lowest physical stack location according to the selected maximum stack size With the following instruction register R2 will be pushed onto the highest physical stack location although the SP is decremented by 2 as for the previous push operation MOV SP 0F802H Set SP before last entry Pe Of physical stack of 256 words ze SP F802H Physical stack addr FA02H PUSH R1 SP F800H Physical stack addr FA00H PUSH R2 SP F7FEH Physical stack addr FBFEH The effect of the address transformation is that the physical stack addresses wrap around from the end of the defined area to its beginning When flushing and filling the internal stack this circular stack mechanism only requires to move that portion of stack data which is really to be re used i e the upper p
122. L These two generic interface lines can each be connected to a number of IO port lines of the C161RI see figure below These connections can be established and released under software control Pe Se SDAx l Generic data line A PC sDAo Module C Generic clock line l ae SCLO l Figure 17 3 PC Bus Line Connections This mechanism allows a number of configurations of the physical I C bus interface Channel switching The PC module can be connected to a specific pair of pins e g SDAO and SCLO which then forms a separate I C channel to the external system The channel can be dynamically switched by connecting the module to another pair of pins e g SDA1 and SCL 1 This establishes physically separate interface channels Broadcasting Connecting the module to more than one pair of pins e g SDAO 1 and SCLO 1 allows the transmission of messages over multiple physical channels at the same time Please note that this configuration is critical when the C161RI is a slave or receives data Note Never change the physical bus interface configuration while a transfer is in progress Semiconductor Group 17 4 1998 05 01 SIEMENS The I2C Bus Module C161RI SCL lC Bus Node lC Bus Node lC Bus Node eg C161RI eg C161RI eg C161RI SCL Figure 17 4 Physical Bus Configuration Example Output Pin Configuration The pin drivers that are assigned to the IC channel s prov
123. LSB Bit Data Bit D8 Parity Wake up Bit Figure 11 4 Asynchronous 9 bit Data Frames Asynchronous transmission begins at the next overflow of the divide by 16 counter see figure above provided that SOR is set and data has been loaded into SOTBUF The transmitted data frame consists of three basic elements the start bit the data field 8 or 9 bits LSB first including a parity bit if selected the delimiter 1 or 2 stop bits Data transmission is double buffered When the transmitter is idle the transmit data loaded into SOTBUF is immediately moved to the transmit shift register thus freeing SOTBUF for the next data to be sent This is indicated by the transmit buffer interrupt request flag SOTBIR being set SOTBUF may now be loaded with the next data while transmission of the previous one is still going on The transmit interrupt request flag SOTIR will be set before the last bit of a frame is transmitted i e before the first or the second stop bit is shifted out of the transmit shift register The transmitter output pin TXDO P3 10 must be configured for alternate data output i e P3 10 1 and DP3 10 2 1 Semiconductor Group 11 6 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Asynchronous reception is initiated by a falling edge 1 to 0 transition on pin RXDO provided that bits SOR and SOREN are set The receive data input pin RXDO is sampled at 16 times the rate of
124. M After the internal state has been saved the trap routine may then execute the PWRDN instruction If the NMI pin is still low at this time Power Down mode will be entered otherwise program execution continues The initialization routine executed upon reset can check the reset identification flags in register WDTCON to determine whether the controller was initially switched on or whether it was properly restarted from Power Down mode The realtime clock RTC can be kept running in Power Down mode in order to maintain a valid system time as long as the supply voltage is applied This enables a system to determine the current time and the duration of the period while it was down by comparing the current time with a timestamp stored when Power Down mode was entered The supply current in this case remains well below 1 mA During power down the voltage at the Vpp pins can be lowered to 2 7 V while the RTC and its selected oscillator will still keep on running and the contents of the internal RAM will still be preserved When the RTC and oscillator is disabled the internal RAM is preserved down to a voltage of 2 5 V Note When the RTC remains active in Power Down mode also the oscillator which generates the RTC clock signal will keep on running of course If the supply voltage is reduced the specified maximum CPU clock frequency for this case must be respected The total power consumption in Power Down mode depends on the active circuitr
125. MOD select special operation modes of the C161RI during reset see table below Make sure to only select valid configurations in order to ensure proper operation of the C161Hl Definition of Special Modes for Reset Configuration P0 5 2 Special Mode Notes POL 5 2 1 1 1 1 Normal Start Default configuration Begin of execution as defined via pin EA 1 1 1 0 Reserved Do not select this configuration 1 1 0 1 Reserved Do not select this configuration 1 1 0 0 Reserved Do not select this configuration 1 0 1 1 Bootstrap Loader Load boot routine via ASCO 10 1 0 Reserved Do not select this configuration 1001 Reserved Do not select this configuration 1 0 0 O Reserved Do not select this configuration O 1 1 1 Reserved Do not select this configuration O 1 1 O Reserved Do not select this configuration O 1 0 1 Reserved Do not select this configuration O 1 0 0 Reserved Do not select this configuration 0 0 X X Reserved Do not select this configuration The on chip Bootstrap Loader allows moving the start code into the internal RAM of the C161RI via the serial interface ASCO The C161RI will remain in bootstrap loader mode until a hardware reset not selecting BSL mode or a software reset Default The C161RI starts fetching code from location 00 0000 the bootstrap loader is off Semiconductor Group 18 10 1998 06 01 SIEMENS System Reset C161RI External
126. ONO is cleared Write Configuration Pin POH 0 WRC selects the initial operation of the control pins WR and BHE during reset When high this pin selects the standard function i e WR control and BHE When low it selects the alternate configuration i e WRH and WRL Thus even the first access after a reset can go to a memory controlled via WRH and WRL This bit is latched in register RPOH and its inverted value is copied into bit WRCFG in register SYSCON Default Standard function WR control and BHE Semiconductor Group 18 11 1998 06 01 SIEMENS System Reset C161RI Chip Select Lines Pins POH 2 and POH 1 CSSEL define the number of active chip select signals during reset This allows the selection which pins of Port 6 drive external CS signals and which are used for general purpose IO The two bits are latched in register RPOH Default All 5 chip select lines active CS4 CSO CSSEL Chip Select Lines Note 1 1 Five CS4 CSO Default without pull downs 10 None Port 6 pins free for IO 0 1 Two CS1 CSO 00 Three CS2 CSO Note The selected number of CS signals cannot be changed via software after reset Segment Address Lines Pins POH 4 and POH 3 SALSEL define the number of active segment address lines during reset This allows the selection which pins of Port 4 drive address lines and which are used for general purpose IO The two bits are latched in register RPOH Depending on t
127. Oscillator Input XTAL1 and Output XTAL2 connect the internal Pierce oscillator to the external crystal The oscillator provides an inverter and a feedback element The standard external oscillator circuitry see chapter Clock Generation comprises the crystal two low end capacitors and series resistor to limit the current through the crystal An external clock signal may be fed to the input XTAL1 leaving XTAL2 open or terminating it for higher input frequencies The Reset Input RSTIN allows to put the C161RI into the well defined reset condition either at power up or external events like a hardware failure or manual reset The input voltage threshold of the RSTIN pin is raised compared to the standard pins in order to minimize the noise sensitivity of the reset input In bidirectional reset mode the C161RI s line RSTIN may be driven active by the chip logic e g in order to support external equipment which is required for startup e g flash memory Bidirectional reset reflects internal reset sources software watchdog also to the RSTIN pin and converts short hardware reset pulses to a minimum duration of the internal reset sequence Bidirectional reset is enabled by setting bit BDRSTEN in register SYSCON and changes RSTIN from a pure input to an open drain IO line When an internal reset is triggered by the SRST instruction or by a watchdog timer overflow or a low level is applied to the RSTIN line an internal driver pulls it low for the du
128. RL WRH if enabled remain inactive high Status of the external bus interface during EBC idle state Pins Internal Accesses only XBUS Accesses PORTO Tristated floating Tristated floating for read accesses XBUS write data for write accesses PORT1 Last used external address Last used XBUS address if used for the bus interface if used for the bus interface Port 4 Last used external segment address Last used XBUS segment address on selected pins on selected pins Port 6 Active external CS signal Inactive high for selected CS signals corresponding to last used address BHE Level corresponding to last external Level corresponding to last XBUS access access ALE Inactive low Pulses as defined for X Peripheral RD Inactive high Inactive high WR WRL Inactive high Inactive high WRH Inactive high Inactive high Semiconductor Group 9 25 1998 06 01 SIEMENS The External Bus Interface C161RI 9 6 TheXBUS Interface The C161RI provides an on chip interface the XBUS interface which allows to connect integrated customer application specific peripherals to the standard controller core The XBUS is an internal representation of the external bus interface i e it is operated in the same way For each peripheral on the XBUS X Peripheral there is a separate address window controlled by a hardwired register pair similar to registers BUSCON and ADDRSEL As an interface to a periph
129. SIEMENS C161RI 16 Bit CMOS Single Chip Microcontroller User s Manual Version 1 0 05 98 05 98 Published by Siemens AG Bereich Halbleiter Marketing Kommunikation BalanstraBe 73 81541 M nchen Siemens AG 1998 All Rights Reserved Attention please As far as patents or other rights of third par ties are concerned liability is only assumed for components not for applications pro cesses and circuits implemented within com ponents or assemblies The information describes the type of compo nent and shall not be considered as assured characteristics Terms of delivery and rights to change design reserved For questions on technology delivery and prices please contact the Semiconductor Group Offices in Germany or the Siemens Companies and Representatives worldwide see address list Due to technical requirements components may contain dangerous substances For in formation on the types in question please contact your nearest Siemens Office Semi conductor Group Siemens AG is an approved CECC manufac turer Packing Please use the recycling operators known to you We can also help you get in touch with your nearest sales office By agreement we will take packing material back if it is sorted You must bear the costs of transport For packing material that is returned to us un sorted or which we are not obliged to accept we shall have to invoice you for any costs in curred
130. STIN Reset Input RSTOUT Reset Output VAREF VAGND Power Supply for Analog Digital Converter VDD VSS Digital Power Supply and Ground 6 pins each The Address Latch Enable signal ALE controls external address latches that provide a stable address in multiplexed bus modes ALE is activated for every external bus cycle independent of the selected bus mode i e it is also activated for bus cycles with a demultiplexed address bus When an external bus is enabled one or more of the BUSACT bits set also X Peripheral accesses will generate an active ALE signal ALE is not activated for internal accesses i e accesses to ROM OTP Flash if provided the internal RAM and the special function registers In single chip mode i e when no external bus is enabled no BUSACT bit set ALE will also remain inactive for X Peripheral accesses During reset an internal pulldown ensures an inactive low level on the ALE output The External Read Strobe RD controls the output drivers of external memory or peripherals when the C161RI reads data from these external devices During accesses to on chip X Peripherals RD remains inactive high During reset an internal pullup ensures an inactive high level on the RD output The External Write Strobe WR WRL controls the data transfer from the C161RI to an external memory or peripheral device This pin may either provide an general WR signal activated for both byte and word write accesses or specifically contr
131. TB if bit AIRDIS 0 IRQD must be cleared via software if bit AIRDIS 1 IRQP EC Interrupt Request Bit for Protocol Events 0 No interrupt request pending 1 A protocol event interrupt request is pending IRQP is set when bit SLA or bit AL is set 4 and must be cleared via software While either IRQD or IRQP is set and the C module is in master mode or has been selected as a slave the I C clock line is held low which prevents further transfers on the PC bus The clock line i e the IPC bus is released when both IRQD and IRQP are cleared Only in this case the next I C bus action can take place Note that IRQD is cleared automatically upon a read or write access to register ICRTB if bit AIRDIS is not set Both interrupt request bits may be set or cleared via software e g to control the I C bus Semiconductor Group 17 10 1998 05 01 SIEMENS The I2C Bus Module C161RI The FC address register ICADR stores the device address ICA which identifies the IPC node when operating in slave mode Bit M10 in register ICCON determines which part of ICADR is valid and used ICADR ED06 XReg Reset Value OXXX 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 z z rw rw rw Bit Function ICA 7 1 Address in 7 bit mode ICA 9 ICA 8 ICA 0 disregarded ICA 0 9 Address in 10 bit mode all bits used The FC Receive Transmit Buffer ICRTB accepts bytes to be transmitted and provide
132. These flags allow branching on specific conditions Support for both signed and unsigned arithmetic is provided through user specifiable branch tests These flags are also preserved automatically by the CPU upon entry into an interrupt or trap routine All targets for branch calculations are also computed in the central ALU A 16 bit barrel shifter provides multiple bit shifts in a single cycle Rotates and arithmetic shifts are also supported Extended Bit Processing and Peripheral Control A large number of instructions has been dedicated to bit processing These instructions provide efficient control and testing of peripherals while enhancing data manipulation Unlike other microcontrollers these instructions provide direct access to two operands in the bit addressable space without requiring to move them into temporary flags The same logical instructions available for words and bytes are also supported for bits This allows the user to compare and modify a control bit for a peripheral in one instruction Multiple bit shift instructions have been included to avoid long instruction streams of single bit shift operations These are also performed in a single machine cycle In addition bit field instructions have been provided which allow the modification of multiple bits from one operand in a single instruction High Performance Branch Call and Loop Processing Due to the high percentage of branching in controller applications branch i
133. Upon the acceptance of an interrupt or the execution of a software TRAP instruction the CSP register is automatically set to zero Semiconductor Group 4 18 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Code Segment 15 CSP Register 0 15 IP Register 0 FF FFFFy 7 255 254 FE 0000 4 M A J TAUN 24 20 18 Bit Physical Code Address 0 000000 A MCA02265 Figure 4 5 Addressing via the Code Segment Pointer Note When segmentation is disabled the IP value is used directly as the 16 bit address Semiconductor Group 4 19 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Data Page Pointers DPPO DPP1 DPP2 DPP3 These four non bit addressable registers select up to four different data pages being active simultaneously at run time The lower 10 bits of each DPP register select one of the 1024 possible 16 Kbyte data pages while the upper 6 bits are reserved for future use The DPP registers allow to access the entire memory space in pages of 16 Kbytes each The DPP registers are implicitly used whenever data accesses to any memory location are made via indirect or direct long 16 bit addressing modes except for override accesses via EXTended instructions and PEC data transfers After reset the Data Page Pointers are initialized in a way that all indirect or direct long 16 bit addresses result in identical 18 b
134. V R3 MDH Move high portion of MD COPYL MOV R4 MDL Move low portion of MD Clears MDRIU RESTORE JNB SAVED DONE Test if MD registers were saved POP MDL Restore registers POP MDH POP MDC BCLR SAVED Multiplication is completed program continues DONE The above save sequence and the restore sequence after COPYL are only required if the current routine could have interrupted a previous routine which contained a MUL or DIV instruction Register MDC is also saved because it is possible that a previous routine s Multiply or Divide instruction was interrupted while in progress In this case the information about how to restart the instruction is contained in this register Register MDC must be cleared to be correctly initialized for a subsequent multiplication or division The old MDC contents must be popped from the stack before the RETI instruction is executed For a division the user must first move the dividend into the MD register If a 16 16 bit division is specified only the low portion of register MD must be loaded The result is also stored into register MD The low portion MDL contains the integer result of the division while the high portion MDH contains the remainder Semiconductor Group 20 2 1998 05 01 SIEMENS System Programming C161RI The following instruction sequence performs a 32 by 16 bit division MOV MDH R1 Move dividend to MD register Sets MDRIU MOV MDL R2 Move low portion to MD DIV R3 Divide
135. W CSR RDY BUS ALE MTT RWD BUSCON4 eb Au E SFR Reset Value 0000 1 0 14 11 CSW CSR RDY BUS ALE MTT RWD Note BUSCONDO is initialized with 0000 if pin EA is high during reset If pin EA is low during reset bits BUSACTO and ALECTLO are set 1 and bit field BTYP is loaded with the bus configuration selected via PORTO Semiconductor Group 9 19 1998 06 01 SIEMENS The External Bus Interface C161RI Bit Function MCTC Memory Cycle Time Control Number of memory cycle time wait states 0000 15 waitstates Number 15 lt MCTC gt 1111 No waitstates RWDCx Read Write Delay Control for BUSCONx 0 With read write delay activate command 1 TCL after falling edge of ALE 1 No read write delay activate command with falling edge of ALE MTTCx Memory Tristate Time Control 0 1 waitstate 1 No waitstate BTYP External Bus Configuration 00 8 bit Demultiplexed Bus 01 8 bit Multiplexed Bus 10 16 bit Demultiplexed Bus 11 16 bit Multiplexed Bus Note For BUSCONO BTYP is defined via PORTO during reset ALECTLx ALE Lengthening Control 0 Normal ALE signal 1 Lengthened ALE signal BUSACTx Bus Active Control 0 External bus disabled 1 External bus enabled within the respective address window see ADDRSEL RDYENx READY Input Enable 0 External bus cycle is controlled by bit field MCTC only 1 External bus cycle is controlled by the READY input signal
136. a Page Ptr 1 Code Seg Ptr MCB02147 Figure 4 1 CPU Block Diagram Semiconductor Group 4 1 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The on chip peripheral units of the C161RI work nearly independent of the CPU with a separate clock generator Data and control information is interchanged between the CPU and these peripherals via Special Function Registers SFRs Whenever peripherals need a non deterministic CPU action an on chip Interrupt Controller compares all pending peripheral service requests against each other and prioritizes one of them If the priority of the current CPU operation is lower than the priority of the selected peripheral request an interrupt will occur Basically there are two types of interrupt processing Standard interrupt processing forces the CPU to save the current program status and the return address on the stack before branching to the interrupt vector jump table PEC interrupt processing steals just one machine cycle from the current CPU activity to perform a single data transfer via the on chip Peripheral Event Controller PEC System errors detected during program execution socalled hardware traps or an external non maskable interrupt are also processed as standard interrupts with a very high priority In contrast to other on chip peripherals there is a closer conjunction between the watchdog timer and the CPU If enabled the watchdog timer expe
137. ad from the result register at the time the next conversion is complete For applications which require less analog input channels the remaining channel inputs can be used as digital input port pins The A D converter of the C161RI supports two different conversion modes In the standard Single Channel conversion mode the analog level on a specified channel is sampled once and converted to a digital result In the Single Channel Continuous mode the analog level on a specified channel is repeatedly sampled and converted without software intervention The Peripheral Event Controller PEC may be used to automatically store the conversion results into a table in memory for later evaluation without requiring the overhead of entering and exiting interrupt routines for each data transfer Real Time Clock The C161RI contains a real time clock RTC which serves for different purposes System clock to determine the current time and date even during idle mode and power down mode optionally Cyclic time based interrupt e g to provide a system time tick independent of the CPU frequency without loading the general purpose timers or to wake up regularly from idle mode 48 bit timer for long term measurements the maximum usable timespan is more than 100 years The RTC module consists of a chain of 3 divider blocks a fixed 8 1 divider the reloadable 16 bit timer T14 and the 32 bit RTC timer accessible via registers RTCH and RTCL Both ti
138. address areas within the address space of the C161RI Within each of these address areas external accesses can be controlled by one of the four different bus modes independent of each other and of the bus mode specified in register BUSCONO Each ADDRSELx register in a way cuts out an address window within which the parameters in register BUSCONXx are used to control external accesses The range start address of such a window defines the upper address bits which are not used within the address window of the specified size see table below For a given window size only those upper address bits of the start address are used marked R which are not implicitly used for addresses inside the window The lower bits of the start address marked x are disregarded Bit field RGSZ Resulting Window Size Relevant Bits R of Start Address A23 A12 0000 4 KByte R RRRRRRR RRR R 0001 8 KByte R RRRR RR RR RR Xx 0010 16 KByte R RRRR RR RR R x x 0011 32 KByte R RRRR RR RR x x x 0100 64 KByte R RR RR RR R x x x x 0101 128 KByte R RRR RRR x X X x X 0110 256 KByte Ho RO RO RR A x ox x X xXx X 0111 512 KByte R HoBRCORSSHRO XX X OK er X X 1000 1 MByte R H H Hox x x x xx x x 1001 2 MByte R RH Hox X X x X Xx X X X 1010 4 MByte R HR x x x X x x X XX 1011 8 MByte R X XXXXXXXXXX 11xx Reserved Semiconductor Group 9 22 1998 06 01 SIEMENS The External Bus Interface C161RI Address Window Arbitration The address windows that
139. al address data bus hold the address data which was output during the last external memory access before entry into Idle mode under the following conditions POH outputs the high byte of the last address if a multiplexed bus mode with 8 bit data bus is used otherwise POH is floating POL is always floating in Idle mode PORT outputs the lower 16 bits of the last address if a demultiplexed bus mode is used otherwise the output pins of PORT1 represent the port latch data Port 4 outputs the segment address for the last access on those pins that were selected during reset otherwise the output pins of Port 4 represent the port latch data During Power Down mode the oscillator except for RTC operation and the clocks to the CPU and to the peripherals are turned off Like in Idle mode all port pins which are configured as general purpose output pins output the last data value which was written to their port output latches When the alternate output function of a port pin is used by a peripheral the state of this pin is determined by the last action of the peripheral before the clocks were switched off Note All pin drivers can be switched off by selecting the general port disable function prior to entering Power Down mode Semiconductor Group 19 5 1998 05 01 SIEMENS Power Management C161RI State of C161RI Output Pins during Idle and Power Down Mode C161RI Output Pin s Idle Mode Power Down Mode if pin drivers are ge
140. al iterations or may directly execute the final application In all cases the C161RI will still run in BSL mode i e with the watchdog timer disabled and limited access to the internal code memory All code fetches from the internal ROM area 00 0000 00 7FFF or 01 0000 01 7FFF if mapped to segment 1 are redirected to the special Boot ROM Data fetches access will access the internal code memory of the C161RI if any is available but will return undefined data on ROMless devices Exiting Bootstrap Loader Mode In order to execute a program in normal mode the BSL mode must be terminated first The C161RI exits BSL mode upon a software reset ignores the level on POL 4 or a hardware reset POL 4 must be high then After a reset the C161RI will start executing from location 00 0000 of the internal ROM or the external memory as programmed via pin EA Choosing the Baudrate for the BSL The calculation of the serial baudrate for ASCO from the length of the first zero byte that is received allows the operation of the bootstrap loader of the C161RI with a wide range of baudrates However the upper and lower limits have to be kept in order to insure proper data transfer fopu Besini 32 SOBRL 1 The C161Hl uses timer T6 to measure the length of the initial zero byte The quantization uncertainty of this measurement implies the first deviation from the real baudrate the next deviation is implied by the computation of the
141. al memory before normal program operation Once the register bank has been selected by programming the CP register the desired portions of the internal memory can easily be initialized via indirect addressing At the end of the initialization the interrupt system may be globally enabled by setting bit IEN in register PSW Care must be taken not to enable the interrupt system before the initialization is complete in order to avoid e g the corruption of internal memory locations by stack operations using an uninitialized stack pointer The software initialization routine should be terminated with the EINIT instruction This instruction has been implemented as a protected instruction Semiconductor Group 18 7 1998 06 01 SIEMENS System Reset C161RI The execution of the EINIT instruction e disables the action of the DISWDT instruction disables write accesses to register SYSCON all configurations regarding register SYSCON enable CLKOUT stacksize etc must be selected before the execution of EINIT disables write accesses to registers SYSCON2 and SYSCONS further write accesses to SYSCON2 and SYSCONGS can be executed only using a special unlock mechanism clears the reset source detection bits in register WDTCON causes the RSTOUT pin to go high this signal can be used to indicate the end of the initialization routine and the proper operation of the microcontroller to external hardware 18 1 System Startup Configurat
142. als timers etc Peripheral PCDDIS PCDDIS except ICD Clock Driver interrupt controller ports RCD fosc ON ON Control via Realtime clock RTC PDCON Clock Driver Note Disabling PCD by setting bit PCDDIS stops the clock signal for all connected modules Make sure that all these modules are in a safe state before stopping their clock signal The port input and output values will not change while PCD is disabled CLKOUT will be high if enabled Please also respect the hints given in section Flexible Peripheral Management of chapter Power Management Semiconductor Group 6 6 1998 05 01 SIEMENS Parallel Ports C161RI 7 Parallel Ports In order to accept or generate single external control signals or parallel data the C161RI provides up to 76 parallel IO lines organized into six 8 bit IO ports PORTO made of POH and POL PORT1 made of P1H and P1L Port 2 Port 6 one 15 bit IO port Port 3 one 7 bit IO port Port 4 and one 6 bit input port Port 5 These port lines may be used for general purpose Input Output controlled via software or may be used implicitly by C161Rl s integrated peripherals or the External Bus Controller All port lines are bit addressable and all input output lines are individually bit wise programmable as inputs or outputs via direction registers except Port 5 of course The IO ports are true bidirectional ports which are switched to high impedance state when configured as
143. alue 0000 14 11 15 13 12 10 9 8 7 6 5 4 3 2 1 0 ACK s s wy w w Jw rw w rw Bit Function M10 Address Mode 0 7 bit addressing using ICA 7 1 1 10 bit addressing using ICA 9 0 RSC Repeated Start Condition 0 Nooperation RSC is cleared automatically after the repeated start condition has been sent 1 Generate a repeated start condition in multi master mode RSC cannot be set in slave mode MOD Basic Operating Mode 00 PC module is disabled and initialized 01 Slave mode 10 Master mode 11 Multi Master mode BUM Busy Master 0 Clearing bit BUM X generates a stop condition 1 Setting bit BUM generates a start condition in multi master mode Note Setting BUM lt while BB 1 generates an arbitration lost situation In this case BUM is cleared and bit AL is set BUM cannot be set in slave mode ACKDIS Acknowledge Pulse Disable 0 Anacknowledge pulse is generated for each received frame 1 No acknowledge pulse is generated AIRDIS Auto Interrupt Reset Disable 0 IRQD is cleared automatically upon a read write access to ICRTB Advantageous if data are read written via PEC transfers 1 IRQD must explicitly be cleared via software Allows to trigger a stop condition after the last data transfer before the bus is released by clearing IRQD TRX Transmit Select 0 Data is received from the C bus 1 Data is transmitted to the I C bus Note TRX is set automatically when writin
144. always OFF in 9 bit data and wake up mode The parity error flag SOPE will be set along with the error interrupt request flag if a wrong parity bit is received The parity bit itself will be stored in bit SORBUF 8 In wake up mode received frames are only transferred to the receive buffer register if the 9th bit the wake up bit is 1 If this bit is 0 no receive interrupt request will be activated and no data will be transferred This feature may be used to control communication in multi processor system When the master processor wants to transmit a block of data to one of several slaves it first sends out an address byte which identifies the target slave An address byte differs from a data byte in that the additional 9th bit is a 1 for an address byte and a 0 for a data byte so no slave will be interrupted by a data byte An address byte will interrupt all slaves operating in 8 bit data wake up bit mode so each slave can examine the 8 LSBs of the received character the address The addressed slave will switch to 9 bit data mode e g by clearing bit SOM 0 which enables it to also receive the data bytes that will be coming having the wake up bit cleared The slaves that were not being addressed remain in 8 bit data wake up bit mode ignoring the following data bytes Semiconductor Group 11 5 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Do Di D2 D3 D4 D5 D7 9th
145. and POL represent the higher and lower part of PORTO respectively Both halfs of PORTO can be written e g via a PEC transfer without effecting the other half If this port is used for general purpose IO the direction of each line can be configured via the corresponding direction registers DPOH and DPOL POL FFOO 80 SFR Reset Value 00 15 14 13 12 11 10 9 8 ae 6 5 4 3 2 1 0 POL 7 POL 6 POL 5 POL 4 POL 3 POL 2 POL 1 POL O POH FF02 81 SFR Reset Value 00 8 7 6 5 4 3 2 1 0 x x rw rw rw rw rw rw rw rw Bit Function POX y Port data register POH or POL bit y DPOL F100 80 ESFR Reset Value 00 15 14 13 12 11 10 9 8 DPOL DPOL DPOL DPOL DPOL DPOL DPOL DPOL 7 6 5 4 3 21 4 2 DPOH F102 81 ESFR Reset Value 00 8 7 6 5 4 3 2 1 0 DPOH DPOH DPOH DPOH 7 6 A 0 i i rw rw rw rw rw rw rw rw Bit Function DPOX y Port direction register DPOH or DPOL bit y DPOX y 0 Port line POX y is an input high impedance DPOX y 1 Port line POX y is an output Semiconductor Group 7 6 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Functions of PORTO When an external bus is enabled PORTO is used as data bus or address data bus Note that an external 8 bit demultiplexed bus only uses POL while POH is free for IO provided that no other bus mode is enabled PORTO is also used to select the system startup configuration During
146. andard inputs of the C161RI determine the status of input signals according to TTL levels In order to accept and recognize noisy signals CMOS like input thresholds can be selected instead of the standard TTL thresholds for all pins of specific ports These special thresholds are defined above the TTL thresholds and feature a defined hysteresis to prevent the inputs from toggling while the respective input signal level is near the thresholds The Port Input Control register PICON allows to select these thresholds for each byte of the indicated ports i e 8 bit ports are controlled by one bit each while 16 bit ports are controlled by two bits each PICON F1C4 E2 ESFR Reset Value 00 8 7 6 5 4 3 2 1 0 wo mw mw Bit Function PxLIN Port x Low Byte Input Level Selection 0 Pins Px 7 Px 0 switch on standard TTL input levels 1 Pins Px 7 Px 0 switch on special threshold input levels PxHIN Port x High Byte Input Level Selection 0 Pins Px 15 Px 8 switch on standard TTL input levels 1 Pins Px 15 Px 8 switch on special threshold input levels All options for individual direction and output mode control are available for each pin independent from the selected input threshold The input hysteresis provides stable inputs from noisy or slowly changing external signals Hysteresis Input level Bit state Figure 7 3 Hysteresis for Special Input Thresholds
147. anwhile When the system reset was caused by a watchdog timer overflow the WDTR Watchdog Timer Reset Indication flag in register WDTCON will be set to 1 This indicates the cause of the internal reset to the software initialization routine WDTR is reset to 0 by an external hardware reset by servicing the watchdog timer or after EINIT After the internal reset has completed the operation of the watchdog timer can be disabled by the DISWDT Disable Watchdog Timer instruction This instruction has been implemented as a protected instruction For further security its execution is only enabled in the time period after a reset until either the SRVWDT Service Watchdog Timer or the EINIT instruction has been executed Thereafter the DISWDT instruction will have no effect Reset Values for the C161RI Registers During the reset sequence the registers of the C161RI are preset with a default value Most SFRs including system registers and peripheral control and data registers are cleared to zero so all peripherals and the interrupt system are off or idle after reset A few exceptions to this rule provide a first pre initialization which is either fixed or controlled by input pins DPP1 0001 points to data page 1 DPP2 0002 points to data page 2 DPP3 0003 points to data page 3 CP FC00 STKUN FC00 STKOV FA00 SP FCO00 WDTCON 00XX value depends on the reset source SORBUF XX undefined SSCRB XXXX unde
148. ardware which controls the peripheral when used as inputs This is called the alternate input or output function of a port pin in contrast to its function as a general purpose IO pin Peripheral Timing Internal operation of CPU and peripherals is based on the CPU clock fGpy The on chip oscillator derives the CPU clock from the crystal or from the external clock signal The clock signal which is gated to the peripherals is independent from the clock signal which feeds the CPU During Idle mode the CPU s clock is stopped while the peripherals continue their operation Peripheral SFRs may be accessed by the CPU once per state When an SFR is written to by software in the same state where it is also to be modified by the peripheral the software write operation has priority Further details on peripheral timing are included in the specific sections about each peripheral Semiconductor Group 2 9 1998 05 01 SIEMENS Architectural Overview C161RI Programming Hints Access to SFRs All SFRs reside in data page 3 of the memory space The following addressing mechanisms allow to access the SFRs indirect or direct addressing with 16 bit mem addresses must guarantee that the used data page pointer DPPO DPP3 selects data page 3 accesses via the Peripheral Event Controller PEC use the SRCPx and DSTPx pointers instead of the data page pointers short 8 bit reg addresses to the standard SFR area do not use the data page poin
149. art of the defined stack area instead of the whole stack area Stack data that remain in the lower part of the internal stack need not be moved by the distance of the space being flushed or filled as the stack pointer automatically wraps around to the beginning of the freed part of the stack area Note This circular stack technique is applicable for stack sizes of 32 to 512 words STKSZ 000 to 100 it does not work with option STKSZ 1118 which uses the complete internal RAM for system stack In the latter case the address transformation mechanism is deactivated Semiconductor Group 20 6 1998 05 01 SIEMENS System Programming C161RI When a boundary is reached the stack underflow or overflow trap is entered where the user moves a predetermined portion of the internal stack to or from the external stack The amount of data transferred is determined by the average stack space required by routines and the frequency of calls traps interrupts and returns In most cases this will be approximately one quarter to one tenth the size of the internal stack Once the transfer is complete the boundary pointers are updated to reflect the newly allocated space on the internal stack Thus the user is free to write code without concern for the internal stack limits Only the execution time required by the trap routines affects user programs The following procedure initializes the controller for usage of the circular stack mechanism
150. arts of this address space are occupied by internal memory areas All addresses which are not used for on chip memory ROM Flash OTP or RAM or for registers may reference external memory locations This external memory is accessed via the C161RI s external bus interface Four memory bank sizes are supported Non segmented mode 64 KByte with A15 AO on PORTO 2 bit segmented mode 256 KByte with A17 A16 on Port 4 and A15 AO on PORTO 4 bit segmented mode 1 MByte with A19 A16 on Port 4 and A15 AO on PORTO 7 bit segmented mode 8 MByte with A22 A16 on Port 4 and A15 AO on PORTO Each bank can be directly addressed via the address bus while the programmable chip select signals can be used to select various memory banks The C161RI also supports four different bus types e Multiplexed 16 bit Bus with address and data on PORTO Default after Reset e Multiplexed 8 bit Bus with address and data on PORTO POL e Demultiplexed 16 bit Bus with address on PORT1 and data on PORTO e Demultiplexed 8 bit Bus with address on PORT1 and data on POL Memory model and bus mode are selected during reset by pin EA and PORTO pins For further details about the external bus configuration and control please refer to chapter The External Bus Interface External word and byte data can only be accessed via indirect or long 16 bit addressing modes using one of the four DPP registers There is no short addressing mode for external o
151. ases except for the sample time the internal capacitances are repeatedly charged and discharged via pins Varer and Vagnp The current that has to be drawn from the sources for sampling and changing charges depends on the time that each respective step takes because the capacitors must reach their final voltage level within the given time at least with a certain approximation The maximum current however that a source can deliver depends on its internal resistance The time that the two different actions during conversion take sampling and converting can be programmed within a certain range in the C161RI relative to the CPU clock The absolute time that is consumed by the different conversion steps therefore is independent from the general speed of the controller This allows adjusting the A D converter of the C161RI to the properties of the system Fast Conversion can be achieved by programming the respective times to their absolute possible minimum This is preferable for scanning high frequency signals The internal resistance of analog source and analog supply must be sufficiently low however High Internal Resistance can be achieved by programming the respective times to a higher value or the possible maximum This is preferable when using analog sources and supply with a high internal resistance in order to keep the current as low as possible The conversion rate in this case may be considerably lower however The conversion time i
152. atch and no direction register Data written to P5 will be lost P5 FFA2 D1 SFR Reset Value XXXX 15 14 11 0 13 12 10 9 8 7 6 5 4 3 2 1 r r r r r r Bit Function P5 y Port data register P5 bit y Read only Alternate Functions of Port 5 Four lines of Port 5 are also connected to the input multiplexer of the Analog Digital Converter These port lines can accept analog signals ANx that can be converted by the ADC For pins that shall be used as analog inputs it is recommended to disable the digital input stage via register P5DIDIS see description below This avoids undesired cross currents and switching noise while the analog input signal level is between V and Vi Some pins of Port 5 also serve as external GPT timer control lines The table below summarizes the alternate functions of Port 5 Port 5 Pin Alternate Function a Alternate Function b P5 0 Analog Input ANO P5 1 Analog Input AN1 P5 2 Analog Input AN2 P5 3 Analog Input AN3 P5 14 T4EUD Timer 4 ext Up Down Input P5 15 T3EUD Timer 2 ext Up Down Input Semiconductor Group 7 23 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Function a b P5 15 T4EUD P5 14 T2EUD Port 5 P5 3 AN3 P5 2 AN2 P5 1 AN1 P5 0 ANO General Purpose A D Converter Timer Control Input Input Input Figure 7 15 Port 5 IO and Alternate Functions Port 5 Digital Input Contr
153. ause for the malfunction When the watchdog timer is enabled and the software has been designed to service it regularly before it overflows the watchdog timer will supervise the program execution as it only will overflow if the program does not progress properly The watchdog timer will also time out if a software error was due to hardware related failures This prevents the controller from malfunctioning for longer than a user specified time Note When the bidirectional reset is enabled also pin RSTIN will be pulled low for the duration of the internal reset sequence upon a watchdog timer reset The watchdog timer provides two registers a read only timer register that contains the current count and a control register for initialization and reset source detection Reset Indication Pin Data Registers Control Registers reor WDTCON Figure 13 1 SFRs and Port Pins associated with the Watchdog Timer The watchdog timer is a 16 bit up counter which can be clocked with the CPU clock fopy either divided by 2 or divided by 128 This 16 bit timer is realized as two concatenated 8 bit timers see figure below The upper 8 bits of the watchdog timer can be preset to a user programmable value via a watchdog service access in order to vary the watchdog expire time The lower 8 bits are reset upon each service access foi MUX WDT Low Byte WDTIN WDT High Byte WDTR RSTOUT Reset WDTREL MCB02052 WDT Control
154. be programmed for slave operation SSCMS 0 Initialization includes the operating mode of the device s SSC and also the function of the respective port lines see Port Control Master Device 1 Device 2 Slave Shift Register Shift Register q Transmit y Receive q Clock e MCS01963 Figure 12 4 SSC Full Duplex Configuration Semiconductor Group 12 6 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI The data output pins MRST of all slave devices are connected together onto the one receive line in this configuration During a transfer each slave shifts out data from its shift register There are two ways to avoid collisions on the receive line due to different slave data Only one slave drives the line i e enables the driver of its MRST pin All the other slaves have to program there MRST pins to input So only one slave can put its data onto the master s receive line Only receiving of data from the master is possible The master selects the slave device from which it expects data either by separate select lines or by sending a special command to this slave The selected slave then switches its MRST line to output until it gets a deselection signal or command The slaves use open drain output on MRST This forms a Wired AND connection The receive line needs an external pullup in this case Corruption of the data on the receive line sent
155. ble below Timer 3 Run Bit The timer can be started or stopped by software through bit T3R Timer T3 Run Bit If T3R 0 the timer stops Setting T3R to 1 will start the timer In gated timer mode the timer will only run if T3R 1 and the gate is active high or low as programmed Semiconductor Group 10 3 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Count Direction Control The count direction of the core timer can be controlled either by software or by the external input pin T3EUD Timer T3 External Up Down Control Input which is the alternate input function of port pin P3 4 These options are selected by bits T3UD and T3UDE in control register T3CON When the up down control is done by software bit T3UDE 0 the count direction can be altered by setting or clearing bit T3UD When T3UDE 1 pin T3EUD is selected to be the controlling source of the count direction However bit T3UD can still be used to reverse the actual count direction as shown in the table below If T3UD 0 and pin T3EUD shows a low level the timer is counting up With a high level at T3EUD the timer is counting down If T3UD 1 a high level at pin T3EUD specifies counting up and a low level specifies counting down The count direction can be changed regardless of whether the timer is running or not When pin T3EUD P3 4 is used as external count direction control input it must be configured as input
156. ble selections C161RI Clock Generation Modes P0 15 13 CPU Frequency External Clock Input Notes POH 7 5 fcpu fosc x F Range 1 1 Reserved Default configuration Reserved Reserved 0 1 0 Reserved 1 faa x1 1 to 20 MHz Direct drive 0 1 0 Reserved T ke 2 to 40 MHz Prescaler operation 1 1 0 0 1 1 0 0 oO o o o Reserved The maximum depends on the duty cycle of the external clock signal In emulation mode pin P0 15 POH 7 is inverted i e the configuration 111 would select direct drive in emulation mode Semiconductor Group 6 5 1998 05 01 SIEMENS Clock Generation C161RI 6 3 Clock Drivers The operating clock signal fopy is distributed to the controller hardware via several clock drivers which are disabled under certain circumstances The real time clock RTC is clocked via a separate clock driver which delivers the prescaled oscillator clock contrary to the other clock drivers The table below summarizes the different clock drivers and their function especially in power reduction modes Clock Drivers Description Clock Driver Clock Active Idle P Down Connected Circuitry Signal mode mode mode CCD fopu ON Off Off CPU memory modules CPU Clock Driver ICD fceu ON ON Off ASCO WDT SSC Interface interrupt detection circuitry Clock Driver PCD fceu Control via Control via Off X Peripher
157. case of missing or excessive EXTR instructions Semiconductor Group 3 8 1998 05 01 SIEMENS Memory Organization C161RI 3 3 The On Chip XRAM The XRAM area is located within data page 3 and provides access to 2 KByte of on chip RAM organized as 1K 16 As the XRAM is connected to the internal XBUS it is accessed like external memory however no external bus cycles are executed for these accesses XRAM accesses are globally enabled or disabled via bit XPEN in register SYSCON This bit is cleared after reset and may be set via software during the initialization to allow accesses to the on chip XRAM When the XRAM is disabled default after reset all accesses to the XRAM area are mapped to external locations The XRAM may be used for both code instructions and data variables user stack tables etc storage Code fetches are always made on even byte addresses The highest possible code storage location in the XRAM is either 00 E7FE for single word instructions or 00 E7FC for double word instructions The respective location must contain a branch instruction unconditional because sequential boundary crossing from XRAM to external memory is not supported and causes erroneous results Any word and byte data read accesses may use the indirect or long 16 bit addressing modes There is no short addressing mode for XRAM operands Any word data access is made to an even byte address The highest possible word data storage location in t
158. cause T6 to overflow In this case ASCO cannot be initialized properly The maximum baudrate B in the figure above is the highest baudrate where the deviation still does not exceed the limit i e all baudrates between B ow and By are below the deviation limit The maximum standard baudrate that fulfills this requirement is 19200 Baud Higher baudrates however may be used as long as the actual deviation does not exceed the limit A certain baudrate marked l in the figure may e g violate the deviation limit while an even higher baudrate marked II in the figure stays very well below it This depends on the host interface Semiconductor Group 15 6 1998 05 01 SIEMENS The Analog Digital Converter C161RI 16 The Analog Digital Converter The C161RI provides an Analog Digital Converter with 8 bit resolution and a sample amp hold circuit on chip A multiplexer selects between up to 4 analog input channels alternate functions of Port 5 The ADC supports the following conversion modes Fixed Channel Single Conversion produces just one result from the selected channel Fixed Channel Continuous Conversion repeatedly converts the selected channel A set of SFRs and port pins provide access to control functions and results of the ADC Ports amp Direction Control Data Registers Control Registers Interrupt Control Alternate Functions ADDAT ADCON ADCIC P5DIDIS ADEIC P5 Port 5 Analog Input Port ANO P5 0 AN3 P
159. ceive interrupt and SSCEIC controls the error interrupt of serial channel SSC Each interrupt source also has its own dedicated interrupt vector SCTINT is the transmit interrupt vector SCRINT is the receive interrupt vector and SCEINT is the error interrupt vector The cause of an error interrupt request receive phase baudrate transmit error can be identified by the error status flags in control register SSCCON Note In contrary to the error interrupt request flag SSCEIR the error status flags SSCxE are not reset automatically upon entry into the error interrupt service routine but must be cleared by software SSCTIC FF72 B9 SFR Reset Value 00 EL ODE 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SSCRIC FF74 BA SFR Reset Value 00 l 19 14 49 12 11 10 9 8 7 SSCEIC FF76 BB SFR Reset Value 00 N COND MCN NUBE UAEK ENIM NE LR WT 0 Note Please refer to the general Interrupt Control Register description for an explanation of the control fields O C1 iN wo D un e Semiconductor Group 12 14 1998 05 01 SIEMENS The Watchdog Timer WDT C161RI 13 The Watchdog Timer WDT To allow recovery from software or hardware failure the C161RI provides a Watchdog Timer If the software fails to service this timer before an overflow occurs an internal reset sequence will be initiated This internal reset will also pull the RSTOUT pin low which also resets the peripheral hardware which might be the c
160. ception on ASCO The initialization of the SCLK pin on the master requires some attention in order to avoid undesired clock transitions which may disturb the other receivers The state of the internal alternate output lines is 1 as long as the SSC is disabled This alternate output signal is ANDed with the respective port line output latch Enabling the SSC with an idle low clock SSCPO 0 will drive the alternate data output and via the AND the port pin SCLK immediately low To avoid this use the following sequence select the clock idle level SSCPO x load the port output latch with the desired clock idle level P3 13 x e switch the pin to output DP3 13 1 e enable the SSC SSCEN 1 if SSCPO 0 enable alternate data output P3 13 1 The same mechanism as for selecting a slave for transmission separate select lines or special commands may also be used to move the role of the master to another device in the network In this case the previous master and the future master previous slave will have to toggle their operating mode SSCMS and the direction of their port pins see description above 12 2 Half Duplex Operation In a half duplex configuration only one data line is necessary for both receiving and transmitting of data The data exchange line is connected to both pins MTSR and MRST of each device the clock line is connected to the SCLK pin The master device controls the
161. ces so POL O should be held high Default Emulation Mode is off Note In emulation mode the direct drive clock option is selected with P0 15 POH 7 1 Adapt Mode Pin POL 1 ADP selects the Adapt Mode when low during reset In this mode the C161RI goes into a passive state which is similar to its state during reset The pins of the C161RlI float to tristate or are deactivated via internal pullup pulldown devices as described for the reset state In addition also the RSTOUT pin floats to tristate rather than be driven low and the on chip oscillator is switched off This mode allows switching a C161RI that is mounted to a board virtually off so an emulator may control the board s circuitry even though the original C161RI remains in its place The original C161RI also may resume to control the board after a reset sequence with POL 1 high Please note that adapt mode overrides any other configuration via PORTO Default Adapt Mode is off Note When XTAL1 is fed by an external clock generator while XTAL2 is left open this clock signal may also be used to drive the emulator device However if a crystal is used the emulator device s oscillator can use this crystal only if at least XTAL2 of the original device is disconnected from the circuitry the output XTAL2 will be driven high in Adapt Mode Semiconductor Group 18 9 1998 06 01 SIEMENS System Reset C161RI Special Operation Modes Pins POL 5 to POL 2 S
162. cesses to related bits see also chapter The Central Processing Unit The following bits are protected Register Bit Name Notes T2IC T3IC T4IC T2IR TSIR TAIR GPT1 timer interrupt request flags T5IC T6IC T5IR T6IR GPT2 timer interrupt request flags CRIC CRIR GPT2 CAPREL interrupt request flag T3CON T6CON TSOTL T60TL GPTx timer output toggle latches SOTIC SOTBIC SOTIR SOTBIR ASCO transmit buffer interrupt request flags SORIC SOEIC SORIR SOEIR ASCO receive error interrupt request flags SOCON SOREN ASCO receiver enable flag SSCTIC SSCRIC SSCTIR SSCRIR SSC transmit receive interrupt request flags SSCEIC SSCEIR SSC error interrupt request flag SSCCON SSCBSY SSC busy flag SSCCON SSCBE SSCPE SSC error flags SSCCON SSCRE SSCTE SSC error flags ADCIC ADEIC ADCIR ADEIR ADC end of conv overrun intr request flag ADCON ADST ADC start flag request flag CC15IC CC8IC CC15IR CC8IR Fast external interrupt request flags TFR TFR 15 14 13 Class A trap flags TFR TFR 7 3 2 1 0 Class B trap flags XP3IC XPOIC XP3IR XPOIC X Peripheral interrupt request flags 44 protected bits Semiconductor Group 2 15 1998 05 01 SIEMENS Memory Organization C161RI 3 Memory Organization The memory space of the C161RI is configured in a Von Neumann architecture This means that code and data are accessed within the same linear address s
163. ch transition of TGOTL is selected to clock the auxiliary timer this concatenation forms a 32 bit or a 33 bit timer counter 32 bit Timer Counter If both a positive and a negative transition of TGOTL is used to clock the auxiliary timer this timer is clocked on every overflow underflow of the core timer T6 Thus the two timers form a 32 bit timer e 33 bit Timer Counter If either a positive or a negative transition of T6OTL is selected to clock the auxiliary timer this timer is clocked on every second overflow underflow of the core timer T6 This configuration forms a 33 bit timer 16 bit core timer T6OTL 16 bit auxiliary timer The count directions of the two concatenated timers are not required to be the same This offers a wide variety of different configurations Tyl CPU Interrupt Clock x feo Core Timer Ty TylR Boios TyR Up Down TyOTL Edge Select Interrupt a Auxiliary Timer Tx Tuis r TxR x25 TXl y 6 Note Line only affected by over underflows of T6 but NOT by software modifications of T6OTL MCS03897 Figure 10 18 Concatenation of Core Timer T6 and Auxiliary Timer T5 Semiconductor Group 10 25 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT2 Capture Reload Register CAPREL in Capture Mode This 16 bit register can be used as a capture register for the auxiliary timer T5 This mode is selected by setting bit T5SC 1 in control register T5CON Bi
164. characteristics because the BUSCONO register is initialized during reset to the slowest possible memory configuration To decrease the number of instructions required to initialize the C161RI each peripheral is programmed to a default configuration upon reset but is disabled from operation These default configurations can be found in the descriptions of the individual peripherals During the software design phase portions of the internal memory space must be assigned to register banks and system stack When initializing the stack pointer SP and the context pointer CP it must be ensured that these registers are initialized before any GPR or stack operation is performed This includes interrupt processing which is disabled upon completion of the internal reset and should remain disabled until the SP is initialized Note Traps incl NMT may occur even though the interrupt system is still disabled In addition the stack overflow STKOV and the stack underflow STKUN registers should be initialized After reset the CP SP and STKUN registers all contain the same reset value 00 FCO00 while the STKOV register contains 00 FA00 With the default reset initialization 256 words of system stack are available where the system stack selected by the SP grows downwards from 00 FBFE while the register bank selected by the CP grows upwards from 00 FCO00 Based on the application the user may wish to initialize portions of the intern
165. chdog 2 12 13 1 18 5 WDT 13 1 24 4 1998 05 01 IE Keyword Index SIEMENS C161RI WDTCON 13 2 X XBUS 2 8 9 26 XPOIC 17 12 XP1IC 17 12 XRAM on chip 3 9 Z ZEROS 4 29 Semiconductor Group 24 5 1998 05 01
166. cked IP value must be incremented by the size of the undefined instruction which is determined by the user before a RETI instruction is executed Protection Fault Trap Whenever one of the special protected instructions is executed where the opcode of that instruction is not repeated twice in the second word of the instruction and the byte following the opcode is not the complement of the opcode the PRTFLT flag in register TFR is set and the CPU enters the protection fault trap routine The protected instructions include DISWDT EINIT IDLE PWRDN SRST and SRVWDT The IP value pushed onto the system stack for the protection fault trap is the address of the instruction that caused the trap Illegal Word Operand Access Trap Whenever a word operand read or write access is attempted to an odd byte address the ILLOPA flag in register TFR is set and the CPU enters the illegal word operand access trap routine The IP value pushed onto the system stack is the address of the instruction following the one which caused the trap Illegal Instruction Access Trap Whenever a branch is made to an odd byte address the ILLINA flag in register TFR is set and the CPU enters the illegal instruction access trap routine The IP value pushed onto the system stack is the illegal odd target address of the branch instruction Illegal External Bus Access Trap Whenever the CPU requests an external instruction fetch data read or data write and no external bus co
167. clock Software Figure 6 4 Frequency Control Paths Semiconductor Group 6 3 1998 05 01 SIEMENS Clock Generation C161RI The internal operation of the C161RI is controlled by the internal CPU clock fopy Both edges of the CPU clock can trigger internal e g pipeline or external e g bus cycles operations see figure below Direct Clock Drive fxraL fopu ITCLITCL Prescaler Operation fxraL fopu TCL TCL SDD Operation fxtaL fou l ll i TCL TCL Figure 6 5 Generation Mechanisms for the CPU Clock Direct Drive When direct drive is configured CLKCFG 011 the C161RI s clock system is directly fed from the external clock input i e fce fosc This allows operation of the C161RI with a reasonably small fundamental mode crystal The specified minimum values for the CPU clock phases TCLs must be respected Therefore the maximum input clock frequency depends on the clock signal s duty cycle Prescaler Operation When prescaler operation is configured CLKCFG 001 the C161RI s input clock is divided by 2 to generate then CPU clock signal i e fopy fosc 2 This requires the oscillator or input clock to run on 2 times the intended operating frequency but guarantees a 50 duty cycle for the internal clock system independent of the input clock signal s waveform Semiconductor Group 6 4 1998 05 01 SIEMENS Clock Generation C161RI The table below lists the possi
168. code segment pointer CSP for code fetches and via an explicit segment number for data accesses overriding the standard DPP scheme During code fetching segments are not changed automatically but rather must be switched explicitly The instructions JMPS CALLS and RETS will do this In larger sequential programs make sure that the highest used code location of a segment contains an unconditional branch instruction to the respective following segment to prevent the prefetcher from trying to leave the current segment Data Pages are contiguous blocks of 16 KByte each They are referenced via the data page pointers DPP3 0 and via an explicit data page number for data accesses overriding the standard DPP scheme Each DPP register can select one of the possible 1024 data pages The DPP register that is used for the current access is selected via the two upper bits of the 16 bit data address Subsequent 16 bit data addresses that cross the 16 KByte data page boundaries therefore will use different data page pointers while the physical locations need not be subsequent within memory Semiconductor Group 3 11 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI 4 The Central Processing Unit CPU Basic tasks of the CPU are to fetch and decode instructions to supply operands for the arithmetic and logic unit ALU to perform operations on these operands in the ALU and to store the previously calculated results As the CPU is the main e
169. configuration In push pull mode a port output driver has an upper and a lower transistor thus it can actively drive the line either to a high or a low level In open drain mode the upper transistor is always switched off and the output driver can only actively drive the line to a low level When writing a 1 to the port latch the lower transistor is switched off and the output enters a high impedance state The high level must then be provided by an external pullup device With this feature it is possible to connect several port pins together to a Wired AND configuration saving external glue logic and or additional software overhead for enabling disabling output signals This feature is controlled through the respective Open Drain Control Registers ODPx which are provided for each port that has this feature implemented These registers allow the individual bit wise selection of the open drain mode for each port line If the respective control bit ODPx y is 0 default after reset the output driver is in the push pull mode If ODPx y is 1 the open drain configuration is selected Note that all ODPx registers are located in the ESFR space A A External ta B Pullup Q a 1Ll Push Pull Output Driver Open Drain Output Driver MCS01975 Figure 7 2 Output Drivers in Push Pull Mode and in Open Drain Mode Semiconductor Group 7 2 1998 05 01 SIEMENS Parallel Ports C161RI Input Threshold Control The st
170. ct portfolios offer powerful development tools for the Siemens C500 and C166 microcontroller families guaranteeing a remarkable variety of price performance classes as well as early availability of high quality key tools such as compilers assemblers simulators debuggers or in circuit emulators Siemens incorporates its strategic tool partners very early into the product development process making sure embedded system developers get reliable well tuned tool solutions which help them unleash the power of Siemens microcontrollers in the most effective way and with the shortest possible learning curve The tool environment for the Siemens 16 bit microcontrollers includes the following tools Compilers C MODULA2 FORTH Macro Assemblers Linkers Locaters Library Managers Format Converters Architectural Simulators HLL debuggers Real Time operating systems VHDL chip models In Circuit Emulators based on bondout or standard chips Plug In emulators Emulation and Clip Over adapters production sockets Logic Analyzer disassemblers Starter Kits Evaluation Boards with monitor programs Industrial boards also for CAN FUZZY PROFIBUS FORTH applications Network driver software CAN PROFIBUS Semiconductor Group 1 6 1998 05 01 SIEMENS Introduction C161RI 1 3 Abbreviations The following acronyms and termini are used within this document ADO eur bs Analog Digital Converter ALE eu oat Address Latch Enable AL V vie
171. ct signal CSCFG 1 becomes active together with the address and BHE if enabled and remains active until the end of the current bus cycle Early address chip select signals are not latched internally and may toggle intermediately while the address is changing Note CS0 provides a latched address chip select directly after reset except for single chip mode when the first instruction is fetched Internal pullup devices hold all CS lines high during reset After the end of a reset sequence the pullup devices are switched off and the pin drivers control the pin levels on the selected CS lines Not selected CS lines will enter the high impedance state and are available for general purpose IO Segment Address versus Chip Select The external bus interface of the C161RI supports many configurations for the external memory By increasing the number of segment address lines the C161RI can address a linear address space of 256 KByte 1 MByte or 8 MByte This allows to implement a large sequential memory area and also allows to access a great number of external devices using an external decoder By increasing the number of CS lines the C161RI can access memory banks or peripherals without external glue logic These two features may be combined to optimize the overall system performance Note Bit SGTDIS of register SYSCON defines if the CSP register is saved during interrupt entry segmentation active or not segmentation disabled Semicondu
172. ction unconditional because sequential boundary crossing from internal ROM to external memory is not supported and causes erroneous results Any word and byte data read accesses may use the indirect or long 16 bit addressing modes There is no short addressing mode for internal ROM operands Any word data access is made to an even byte address The highest possible word data storage location in the internal ROM is xx xxFE For PEC data transfers the internal ROM can be accessed independent of the contents of the DPP registers via the PEC source and destination pointers The internal ROM is not provided for single bit storage and therefore it is not bit addressable Note The x in the locations above depend on the available ROM Flash memory and on the mapping The internal ROM may be enabled disabled or mapped into segment O or segment 1 under software control Chapter System Programming shows how to do this and reminds of the precautions that must be taken in order to prevent the system from crashing Semiconductor Group 3 3 1998 05 01 SIEMENS Memory Organization C161RI 3 2 Internal RAM and SFR Area The RAM SFR area is located within data page 3 and provides access to the internal RAM IRAM organized as Xx16 and to two 512 Byte blocks of Special Function Registers SFRs The C161RI provides 1 KByte of IRAM 00 FFFF ud ee ae 7 ZT 00 FFFF IRAM SFR m 00 F000 O 00 E000 a S N A Reserved Ext Me
173. ctor Group 9 9 1998 06 01 SIEMENS The External Bus Interface C161RI 9 2 Programmable Bus Characteristics Important timing characteristics of the external bus interface have been made user programmable to allow to adapt it to a wide range of different external bus and memory configurations with different types of memories and or peripherals The following parameters of an external bus cycle are programmable ALE Control defines the ALE signal length and the address hold time after its falling edge Memory Cycle Time extendable with 1 15 waitstates defines the allowable access time Memory Tri State Time extendable with 1 waitstate defines the time for a data driver to float Read Write Delay Time defines when a command is activated after the falling edge of ALE READY Control defines if a bus cycle is terminated internally or externally Note Internal accesses are executed with maximum speed and therefore are not programmable External accesses use the slowest possible bus cycle after reset The bus cycle timing may then be optimized by the initialization software ALE N ALECTL MCTC MTTC MCD02225 Figure 9 5 Programmable External Bus Cycle Semiconductor Group 9 10 1998 06 01 SIEMENS The External Bus Interface C161RI ALE Length Control The length of the ALE signal and the address hold time after its falling edge are cont
174. ctor location related to the corresponding source PEC services are very well suited for example to move register contents to from a memory table The C161RI has 8 PEC channels each of which offers such fast interrupt driven data transfer capabilities Memory Areas The memory space of the C161RI is configured in a Von Neumann architecture which means that code memory data memory registers and IO ports are organized within the same linear address space which covers up to 16 MBytes The entire memory space can be accessed bytewise or wordwise Particular portions of the on chip memory have additionally been made directly bit addressable A 1 KByte 16 bit wide internal RAM provides fast access to General Purpose Registers GPRs user data variables and system stack The internal RAM may also be used for code A unique decoding scheme provides flexible user register banks in the internal memory while optimizing the remaining RAM for user data The CPU disposes of an actual register context consisting of up to 16 wordwide and or bytewide GPRs which are physically located within the on chip RAM area A Context Pointer CP register determines the base address of the active register bank to be accessed by the CPU at a time The number of register banks is only restricted by the available internal RAM space For easy parameter passing a register bank may overlap others A system stack of up to 512 words is provided as a storage for temporary data
175. cts to be serviced by the CPU within a programmable period of time otherwise it will reset the chip Thus the watchdog timer is able to prevent the CPU from going totally astray when executing erroneous code After reset the watchdog timer starts counting automatically but it can be disabled via software if desired Beside its normal operation there are the following particular CPU states Reset state Any reset hardware software watchdog forces the CPU into a predefined active state IDLE state The clock signal to the CPU itself is switched off while the clocks for the on chip peripherals keep running POWER DOWN state All of the on chip clocks are switched off RTC clock selectable A transition into an active CPU state is forced by an interrupt if being IDLE or by a reset if being in POWER DOWN mode The IDLE POWER DOWN and RESET states can be entered by particular C161RI system control instructions A set of Special Function Registers is dedicated to the functions of the CPU core General System Configuration SYSCON RPOH CPU Status Indication and Control PSW Code Access Control IP CSP Data Paging Control DPPO DPP1 DPP2 DPP3 GPRs Access Control CP System Stack Access Control SP STKUN STKOV Multiply and Divide Support MDL MDH MDC ALU Constants Support ZEROS ONES Semiconductor Group 4 2 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI 4 1
176. d Reserved Do not use this combination TxR Timer x Run Bit TxR 2 0 Timer Counter x stops TxR 1 Timer Counter x runs TxUD Timer x Up Down Control TxUDE Timer x External Up Down Enable For the effects of bits TxUD and TxUDE refer to the direction table see T3 section Semiconductor Group 10 11 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Note The auxiliary timers have no output toggle latch and no alternate output function Count Direction Control for Auxiliary Timers The count direction of the auxiliary timers can be controlled in the same way as for the core timer T3 The description and the table apply accordingly Timers T2 and T4 in Timer Mode or Gated Timer Mode When the auxiliary timers T2 and T4 are programmed to timer mode or gated timer mode their operation is the same as described for the core timer T3 The descriptions figures and tables apply accordingly with one exception There is no output toggle latch for T2 and T4 Timers T2 and T4 in Incremental Interface Mode When the auxiliary timers T2 and T4 are programmed to incremental interface mode their operation is the same as described for the core timer T3 The descriptions figures and tables apply accordingly Semiconductor Group 10 12 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timers T2 and T4 in Counter Mode Counter mode for the auxiliary timers T2 and T4 is selected by setting bi
177. d Node 155 4 Reserved Reserved 3J2 Reserved for PLL OWD XPSIC 1 0 RTC XP3IC Note In order to ensure compatibility with other derivatives application software should never set reserved bits within register ISNC Bits PLLIE and PLLIR are not implemented but reserved for compatibility with devices providing a PLL Semiconductor Group 5 20 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 6 External Interrupts Although the C161RI has no dedicated INTR input pins it provides many possibilities to react on external asynchronous events by using a number of IO lines for interrupt input The interrupt function may either be combined with the pin s main function or may be used instead of it i e if the main pin function is not required Interrupt signals may be connected to EX7IN EXOIN the fast external interrupt input pins TAIN T2IN the timer input pins CAPIN the capture input of GPT2 For each of these pins either a positive a negative or both a positive and a negative external transition can be selected to cause an interrupt or PEC service request The edge selection is performed in the control register of the peripheral device associated with the respective port pin The peripheral must be programmed to a specific operating mode to allow generation of an interrupt by the external signal The priority of the interrupt request is determined by the interrupt control register of the respective peri
178. d STKUN Stack Underflow Pointer Specific system traps Stack Overflow trap Stack Underflow trap will be entered whenever the SP reaches either boundary specified in these registers The contents of the stack pointer are compared to the contents of the overflow register whenever the SP is DECREMENTED either by a CALL PUSH or SUB instruction An overflow trap will be entered when the SP value is less than the value in the stack overflow register The contents of the stack pointer are compared to the contents of the underflow register whenever the SP is INCREMENTED either by a RET POP or ADD instruction An underflow trap will be entered when the SP value is greater than the value in the stack underflow register Note When a value is MOVED into the stack pointer NO check against the overflow underflow registers is performed In many cases the user will place a software reset instruction SRST into the stack underflow and overflow trap service routines This is an easy approach which does not require special programming However this approach assumes that the defined internal stack is sufficient for the current software and that exceeding its upper or lower boundary represents a fatal error It is also possible to use the stack underflow and stack overflow traps to cache portions of a larger external stack Only the portion of the system stack currently being used is placed into the internal memory thus allowing a greater portion of the
179. d T4IN must be set to 0 and the level of the capture trigger signal should be held high or low for at least 8 fce cycles before it changes to ensure correct edge detection Semiconductor Group 10 17 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Interrupt Control for GPT1 Timers When a timer overflows from FFFF to 0000 when counting up or when it underflows from 0000 to FFFF when counting down its interrupt request flag T2IR TSIR or T4IR in register TxIC will be set This will cause an interrupt to the respective timer interrupt vector T2INT T3INT or T4INT or trigger a PEC service if the respective interrupt enable bit T2IE T3IE or T4IE in register TxIC is set There is an interrupt control register for each of the three timers T2IC FF60 BO SFR Reset Value 00 EL ONE LM NELLE S ER RENI 6 T2IR T2IE ILVL GLVL nw rw rw T3IC FF62 B1 SFR Reset Value 00 19 I4 o 13 T2 Ti To ENS NI 6 T3IR T3IE ILVL GLVL rw rw rw T4IC FF64 B2 SFR Reset Value 00 6 srr prrsreeee 7 5 4 3 2 1 0 TAIR TAIE ILVL GLVL rw rw rw rw Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Semiconductor Group 10 18 1998 05 01 SIEMENS The General Purpose Timer Units C161RI 10 2 Timer Block GPT2 From a programmer s point of view the GPT2 block is represented
180. d for Slow Down operation bypassing the basic clock path used for standard operation The programmable Slow Down Divider SDD divides the oscillator frequency by a factor of 1 32 which is specified via bitfield CLKREL in register SYSCON2 When bitfield CLKREL is written during SDD operation the reload counter will output one more clock pulse with the old frequency in order to resynchronize internally before generating the new frequency UM cr ERN M EE CLKREL Reload Counter fosc soo ete E EN Eds EE Lim due au Ernie Om eme eme Figure 19 3 Slow Down Divider Operation Using e g a 5 MHz input clock the on chip logic may be run at a frequency down to 156 25 KHz without an external hardware change Note During Slow Down operation the whole device including bus interface and generation of signal CLKOUT is clocked with the asymmetrical SDD clock see figure above All these clock options are selected via bitfield CLKCON in register SYSCON2 A state machine controls the switching mechanism itself and ensures a continuous and glitch free clock signal to the on chip logic Switching to Slow Down operation affects frequency sensitive peripherals like serial interfaces timers PWM etc If these units are to be operated in Slow Down mode their precalers or reload values must be adapted Please note that the reduced CPU frequency decreases e g timer resolution and increases the step width e g for baudrate generati
181. d from these two input signals so the contents of timer Tx corresponds to the sensor position The third position sensor signal TOPO can be connected to an interrupt input The count direction up down for each timer is programmable by software or may additionally be altered dynamically by an external signal TxEUD to facilitate e g position tracking The core timers T3 and T6 have output toggle latches TxOTL which change their state on each timer over flow underflow The state of these latches may be used internally to concatenate the core timers with the respective auxiliary timers resulting in 32 33 bit timers counters for measuring long time periods with high resolution Various reload or capture functions can be selected to reload timers or capture a timer s contents triggered by an external signal or a selectable transition of toggle latch TxOTL The maximum resolution of the timers in module GPT1 is 8 CPU clock cycles 2 16 TCL With their maximum resolution of 4 CPU clock cycles 2 8 TCL the GPT2 timers provide precise event control and time measurement Watchdog Timer The Watchdog Timer represents one of the fail safe mechanisms which have been implemented to prevent the controller from malfunctioning for longer periods of time The Watchdog Timer is always enabled after a reset of the chip and can only be disabled in the time interval until the EINIT end of initialization instruction has been executed Thus the chip s start
182. d sequence this counter is restarted with the value of the new instruction This allows the construction of locked sequences longer than 4 instructions Note Interrupt latencies may be increased when using locked code sequences PEC requests are not serviced during idle mode if the IDLE instruction is part of a locked sequence Semiconductor Group 20 13 1998 05 01 SIEMENS System Programming C161RI 20 10 Handling the Internal Code Memory The Mask ROM OTP Flash versions of the C161RI provide on chip code memory that may store code as well as data The lower 32 KByte of this code memory are referred to as the internal ROM area Access to this internal ROM area is controlled during the reset configuration and via software The ROM area may be mapped to segment 0 to segment 1 or the code memory may be disabled at all Note The internal ROM area always occupies an address area of 32 KByte even if the implemented mask ROM OTP Flash memory is smaller than that e g 8 KByte Of course the total implemented memory may exceed 32 KBytes Code Memory Configuration during Reset The control input pin EA External Access enables the user to define the address area from which the first instructions after reset are fetched When EA is low 0 during reset the internal code memory is disabled and the first instructions are fetched from external memory When EA is high 1 during reset the internal code memory is globally enabl
183. data transfer by generating the shift clock while the slave devices receive it Due to the fact that all transmit and receive pins are connected to the one data exchange line serial data may be moved between arbitrary stations Similar to full duplex mode there are two ways to avoid collisions on the data exchange line only the transmitting device may enable its transmit pin driver the non transmitting devices use open drain output and only send ones Since the data inputs and outputs are connected together a transmitting device will clock in its own data at the input pin MRST for a master device MTSR for a slave By these means any corruptions on the common data exchange line are detected where the received data is not equal to the transmitted data Semiconductor Group 12 8 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI Master Device 1 Device 2 Slave Shift Register Common Transmit Receive Device 3 Slave MCS01965 Figure 12 5 SSC Half Duplex Configuration Continuous Transfers When the transmit interrupt request flag is set it indicates that the transmit buffer SSCTB is empty and ready to be loaded with the next transmit data If SSCTB has been reloaded by the time the current transmission is finished the data is immediately transferred to the shift register and the next transmission will start without any additional delay On the data lin
184. dex C161RI 24 Keyword Index This section lists a number of keywords which refer to specific details of the C161RI in terms of its architecture its functional units or functions This helps to quickly find the answer to specific questions about the C161RI A Acronyms 1 7 Adapt Mode 18 9 ADC 2 13 16 1 ADCIC ADEIC 16 6 ADCON 16 3 Address Arbitration 9 23 Area Definition 9 22 Boundaries 3 11 Segment 9 8 18 12 ADDRSELx 9 21 9 23 ALE length 9 11 ALU 4 14 Analog Digital Converter 2 13 16 1 Arbitration Address 9 23 ASCO 11 1 Asynchronous mode 11 4 Baudrate 11 10 Error Detection 11 10 Interrupts 11 12 Synchronous mode 11 8 Asynchronous Serial Interface gt ASCO 11 1 B Baudrate ASCO 11 10 Bootstrap Loader 15 5 PC Bus 17 8 SSC 12 10 BHE 7 19 9 7 Bidirectional reset 18 3 Bit addressable memory 3 5 Handling 4 9 Manipulation Instructions 22 2 protected 2 15 4 9 Bootstrap Loader 15 1 18 10 Boundaries 3 11 Semiconductor Group 24 1 Bus CAN 2 11 Demultiplexed 9 4 Idle State 9 25 Mode Configuration 9 2 18 11 Multiplexed 9 3 Physical IPC 17 4 BUSCONXx 9 19 9 23 C CAN Interface 2 11 Capture Mode GPT1 10 17 GPT2 CAPREL 10 26 CCxIC 5 23 Chip Select Configuration 9 8 18 12 Latched Early 9 9 Clock distribution 6 1 19 10 generator modes 6 5 18 13 Concatenation of Timers 10 14 10 25 Configuration Address 9 8 18 12 Bus Mode 9 2 18 11 Chip Select 9 8 18 12 PLL 6 5 18 13 Reset 18 6
185. dified and the respective PEC channel services any request until it is disabled again When COUNT is decremented from 01 to 00 after a transfer the request flag is not cleared which generates another request from the same source When COUNT already contains the value 00 the respective PEC channel remains idle and the associated interrupt service routine is activated instead This allows to choose if a level 15 or 14 request is to be serviced by the PEC or by the interrupt service routine Note PEC transfers are only executed if their priority level is higher than the CPU level i e only PEC channels 7 4 are processed while the CPU executes on level 14 All interrupt request sources that are enabled and programmed for PEC service should use different channels Otherwise only one transfer will be performed for all simultaneous requests When COUNT is decremented to 00 and the CPU is to be interrupted an incorrect interrupt vector will be generated Semiconductor Group 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI The source and destination pointers specify the locations between which the data is to be moved A pair of pointers SRCPx and DSTPx is associated with each of the 8 PEC channels These pointers do not reside in specific SFRs but are mapped into the internal RAM of the C161RI just below the bit addressable area see figure below 00 FCFE 00 FCEE 00 FCFC 00 FCEC 00 FCFA 00 FCEA 00 FCF8
186. ding of all data page pointers is required This also applies to re mapping the internal ROM area to segment 0 Enabling the internal code memory after reset When enabling the internal code memory after having booted the system from external memory note that the C161RI will then access the internal memory using the current segment offset rather than accessing external memory Disabling the internal code memory after reset When disabling the internal code memory after having booted the system from there note that the C161RI will not access external memory before a jump to segment 0 in this case is executed General Rules When mapping the code memory no instruction or data accesses should be made to the internal memory otherwise unpredictable results may occur To avoid these problems the instructions that configure the internal code memory should be executed from external memory or from the on chip RAM Whenever the internal code memory is disabled enabled or remapped the DPPs must be explicitly re loaded to enable correct data accesses to the internal and or external memory Semiconductor Group 20 15 1998 05 01 SIEMENS The Register Set C161RI 21 The Register Set This section summarizes all registers which are implemented in the C161RI and explains the description format which is used in the chapters describing the function and layout of the SFRs For easy reference the registers are ordered according to two different ke
187. directional Reset Operation Bidirectional reset reflects internal reset sources software watchdog also to the RSTIN pin and converts short hardware reset pulses to a minimum duration of the internal reset sequence Bidirectional reset is enabled by setting bit BDRSTEN in register SYSCON and changes RSTIN from a pure input to an open drain IO line When an internal reset is triggered by the SRST instruction or by a watchdog timer overflow or a low level is applied to the RSTIN line an internal driver pulls it low for the duration of the internal reset sequence After that it is released and is then controlled by the external circuitry alone The Bidirectional reset function is useful in applications where external devices require a defined reset signal but cannot be connected to the C161RIl s RSTOUT signal e g an external flash memory which must come out of reset and deliver code well before RSTOUT can be deactivated via EINIT The following behavior differences must be observed when using the Bidirectional reset feature in an application e Bit BDRSTEN in register SYSCON cannot be changed after EINIT e After a reset bit BDRSTEN is cleared The reset indication flags always indicate a long hardware reset e The PORTO configuration is treated like on a hardware reset Especially the bootstrap loader may be activated when POL 4 is low e Pin RSTIN may only be connected to external reset devices with an open drain output driver
188. e Software Reset The reset sequence can be triggered at any time via the protected instruction SRST Software Reset This instruction can be executed deliberately within a program e g to leave bootstrap loader mode or upon a hardware trap that reveals a system failure Note A software reset disregards the configuration of POL 5 POL O Watchdog Timer Reset When the watchdog timer is not disabled during the initialization or serviced regularly during program execution is will overflow and trigger the reset sequence Other than hardware and software reset the watchdog reset completes a running external bus cycle if this bus cycle either does not use READY at all or if READY is sampled active low after the programmed waitstates When READY is sampled inactive high after the programmed waitstates the running external bus cycle is aborted Then the internal reset sequence is started Note A watchdog reset disregards the configuration of POL 5 POL O The watchdog reset cannot occur while the C161RI is in bootstrap loader mode Semiconductor Group 18 2 1998 06 01 SIEMENS System Reset C161RI Bidirectional Reset In a special mode Bidirectional reset the C161RI s line RSTIN normally an input may be driven active by the chip logic e g in order to support external equipment which is required for startup e g flash memory RSTIN Internal Circuitry amp Reset sequence active BDRSTEN 1 Figure 18 2 Bi
189. e 5 words js Of the current system stack Semiconductor Group 20 10 1998 05 01 SIEMENS System Programming C161RI 20 4 Table Searching A number of features have been included to decrease the execution time required to search tables First branch delays are eliminated by the branch target cache after the first iteration of the loop Second in non sequentially searched tables the enhanced performance of the ALU allows more complicated hash algorithms to be processed to obtain better table distribution For sequentially searched tables the auto increment indirect addressing mode and the E end of table flag stored in the PSW decrease the number of overhead instructions executed in the loop The two examples below illustrate searching ordered tables and non ordered tables respectively MOV RO BASE Move table base into RO LOOP CMP R1 RO Compare target to table entry JMPR cc SGT LOOP Test whether target has not been found Note The last entry in the table must be greater than the largest possible target MOV RO BASE Move table base into RO LOOP CMP R1 RO Compare target to table entry JMPR cc NET LOOP Test whether target is not found AND the end of table has not been reached Note The last entry in the table must be equal to the lowest signed integer 8000 20 5 Peripheral Control and Interface All communication between peripherals and the CPU is performed either by PEC transfers to and
190. e IDLE instruction has been implemented as a protected 32 bit instruction Idle mode is terminated by interrupt requests from any enabled interrupt source whose individual Interrupt Enable flag was set before the Idle mode was entered regardless of bit IEN For a request selected for CPU interrupt service the associated interrupt service routine is entered if the priority level of the requesting source is higher than the current CPU priority and the interrupt system is globally enabled After the RETI Return from Interrupt instruction of the interrupt service routine is executed the CPU continues executing the program with the instruction following the IDLE instruction Otherwise if the interrupt request cannot be serviced because of a too low priority or a globally disabled interrupt system the CPU immediately resumes normal program execution with the instruction following the IDLE instruction Semiconductor Group 19 2 1998 05 01 SIEMENS Power Management C161RI For a request which was programmed for PEC service a PEC data transfer is performed if the priority level of this request is higher than the current CPU priority and the interrupt system is globally enabled After the PEC data transfer has been completed the CPU remains in Idle mode Otherwise if the PEC request cannot be serviced because of a too low priority or a globally disabled interrupt system the CPU does not remain in Idle mode but continues program execution with the instr
191. e RDYENx bits in the BUSCON registers When this function is selected RDYENx 1 only the lower 3 bits of the respective MCTC bit field define the number of inserted waitstates 0 7 while the MSB of bit field MCTC selects the READY operation MCTC 3 0 Synchronous READY i e the READY signal must meet setup and hold times MCTO 3 1 Asynchronous READY i e the READY signal is synchronized internally The Synchronous READY provides the fastest bus cycles but requires setup and hold times to be met The CLKOUT signal should be enabled and may be used by the peripheral logic to control the HEADY timing in this case The Asynchronous READY is less restrictive but requires additional waitstates caused by the internal synchronization As the asynchronous READY is sampled earlier see figure above programmed waitstates may be necessary to provide proper bus cycles see also notes on normally ready peripherals below Semiconductor Group 9 15 1998 06 01 SIEMENS The External Bus Interface C161RI A READY signal especially asynchronous READY that has been activated by an external device may be deactivated in response to the trailing rising edge of the respective command RD or WR Note When the READY function is enabled for a specific address window each bus cycle within this window must be terminated with an active READY signal Otherwise the controller hangs until the next reset A timeout funct
192. e Trap Flag Register TFR allows a trap service routine to identify the kind of trap which caused the exception Each trap function is indicated by a separate request flag When a hardware trap occurs the corresponding request flag in register TFR is set to 1 TFR FFAC D6 SFR Reset Value 0000 15 14 13 12 1 10 9 8 7 6 5 4 3 2 i 0 Bit Function ILLBUS Illegal External Bus Access Flag An external access has been attempted with no external bus defined ILLINA Illegal Instruction Access Flag A branch to an odd address has been attempted ILLOPA Illegal Word Operand Access Flag A word operand access read or write to an odd address has been attempted PRTFLT Protection Fault Flag A protected instruction with an illegal format has been detected UNDOPC Undefined Opcode Flag The currently decoded instruction has no valid C161RI opcode STKUF Stack Underflow Flag The current stack pointer value exceeds the content of register STKUN STKOF Stack Overflow Flag The current stack pointer value falls below the content of register STKOV NMI Non Maskable Interrupt Flag A negative transition falling edge has been detected on pin NMI Semiconductor Group 5 25 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Note The trap service routine must clear the respective trap flag otherwise a new trap will be requested after exiting the service routine Setting a trap request flag by software ca
193. e allows the core CPU to process portions of multiple sequential instruction stages in parallel The following four stage pipeline provides the optimum balancing for the CPU core FETCH In this stage an instruction is fetched from the internal ROM or RAM or from the external memory based on the current IP value DECODE In this stage the previously fetched instruction is decoded and the required operands are fetched EXECUTE In this stage the specified operation is performed on the previously fetched operands WRITE BACK In this stage the result is written to the specified location If this technique were not used each instruction would require four machine cycles This increased performance allows a greater number of tasks and interrupts to be processed Instruction Decoder Instruction decoding is primarily generated from PLA outputs based on the selected opcode No microcode is used and each pipeline stage receives control signals staged in control registers from the decode stage PLAs Pipeline holds are primarily caused by wait states for external memory accesses and cause the holding of signals in the control registers Multiple cycle instructions are performed through instruction injection and simple internal state machines which modify required control signals High Function 8 bit and 16 bit Arithmetic and Logic Unit All standard arithmetic and logical operations are performed in a 16 bit ALU In addition for byte operations
194. e below The instructions of the unlock sequence including the intended write access must be secured with an EXTR instruction switch to ESFR space and lock interrupts Note The unlock sequence provides no write access to register SYSCON SYSCON2 SYSCONS Unlock Sequence Step SYSRLS Instruction Notes 0000 Status before release sequence 1001 BFLDL OR ORB XOR XORB Read Modify Write access 0011 MOV MOVB MOVBS MOVBZ Write access 0111p BSET BMOV BMOVN Read Modify Write access BOR BXOR bit instruction 4 Single read modify write access to SYSCON or SYSCONS 100009 Status after release sequence Note SYSRLS must be set to 0000 before the first step if any OR command is used 2 Usually byte accesses should not be used for special function registers 3 SYSRLS is cleared by hardware if unlock sequence and write access were successful SYSRLS shows the last value written otherwise Semiconductor Group 19 12 1998 05 01 SIEMENS Power Management C161RI The code examples below show how an access to SYSCON2 SYSCONG can be accomplished in an application ENTER SLOWDOWN EXTR 4H BFLDL SYSCON2 0FH 09H MOV SYSCON2 0003H BSET SYSCON2 2 BFLDH SYSCON2 03H 01H EXIT SLOWDOWN EXTR 4H BFLDL SYSCON2 0FH 09H MOV SYSCON2 0003H BSET SYSCON2 2 BFLDH SYSCON2 03H 00H Semiconductor Group Curr
195. e default level of the CPU Therefore a request on level 0 will never be serviced because it can never interrupt the CPU However an enabled interrupt request on level 0000 will terminate the C161RI s Idle mode and reactivate the CPU For interrupt requests which are to be serviced by the PEC the associated PEC channel number is derived from the respective ILVL LSB and GLVL see figure below So programming a source to priority level 15 ILVL 11115 selects the PEC channel group 7 4 programming a source to priority level 14 ILVL 11105 selects the PEC channel group 3 0 The actual PEC channel number is then determined by the group priority field GLVL Interrupt f Control Register ILVL GEVE PEC Control Figure 5 1 Priority Levels and PEC Channels Simultaneous requests for PEC channels are prioritized according to the PEC channel number where channel 0 has lowest and channel 8 has highest priority Note All sources that request PEC service must be programmed to different PEC channels Otherwise an incorrect PEC channel may be activated Semiconductor Group 5 7 1998 05 01 Interrupt and Trap Functions C161RI SIEMENS The table below shows in a few examples which action is executed with a given programming of an interrupt control register Priority Level Type of Service ILVL GLVL COUNT 00H COUNT 00 1111 11 CPU interrupt PEC service level 15 group pri
196. e instructions known from other microcontrollers that can be replaced by the following instructions of the C161RI Substituted Instruction C161RI Instruction Function CLR Hn AND Rn 0 Clear register CPLB Bit BMOVN Bit Bit Complement bit DEC Rn SUB Rn 1 Decrement register INC Rn ADD Rn 1 Increment register SWAPB Rn ROR Rn 84 Swap bytes within word Modification of System Flags is performed using bit set or bit clear instructions BSET BCLR All bit and word instructions can access the PSW register so no instructions like CLEAR CARRY or ENABLE INTERRUPTS are required External Memory Data Access does not require special instructions to load data pointers or explicitly load and store external data The C161RI provides a Von Neumann memory architecture and its on chip hardware automatically detects accesses to internal RAM GPRs and SFRs Multiplication and Division Multiplication and division of words and double words is provided through multiple cycle instructions implementing a Booth algorithm Each instruction implicitly uses the 32 bit register MD MDL lower 16 bits MDH upper 16 bits The MDRIU flag Multiply or Divide Register In Use in register MDC is set whenever either half of this register is written to or when a multiply divide instruction is started It is cleared whenever the MDL register is read Because an interrupt can be acknowledged before the contents of register MD are saved th
197. e machine to provide the time needed to process instructions which cannot be processed within one machine cycle They are automatically injected into the decode stage of the pipeline and then they pass through the remaining stages like every standard instruction Program interrupts are performed by means of injected instructions too Although these internally injected instructions will not be noticed in reality they are introduced here to ease the explanation of the pipeline in the following Sequential Instruction Processing Each single instruction has to pass through each of the four pipeline stages regardless of whether all possible stage operations are really performed or not Since passing through one pipeline stage takes at least one machine cycle any isolated instruction takes at least four machine cycles to be completed Pipelining however allows parallel i e simultaneous processing of up to four instructions Thus most of the instructions seem to be processed during one machine cycle as soon as the pipeline has been filled once after reset see figure below Instruction pipelining increases the average instruction throughput considered over a certain period of time In the following any execution time specification of an instruction always refers to the average execution time due to pipelined parallel instruction processing Semiconductor Group 4 3 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI
198. e performed using software Standard multiple precision instructions are used to perform calculations on data types that exceed the size of the ALU Multiple bit rotate and logic instructions allow easy masking and extracting of portions of floating point numbers To decrease the time required to perform floating point operations two hardware features have been implemented in the CPU core First the PRIOR instruction aids in normalizing floating point numbers by indicating the position of the first set bit in a GPR This result can the be used to rotate the floating point result accordingly The second feature aids in properly rounding the result of normalized floating point numbers through the overflow V flag in the PSW This flag is set when a one is shifted out of the carry bit during shift right operations The overflow flag and the carry flag are then used to round the floating point result based on the desired rounding algorithm 20 7 Trap Interrupt Entry and Exit Interrupt routines are entered when a requesting interrupt has a priority higher than the current CPU priority level Traps are entered regardless of the current CPU priority When either a trap or interrupt routine is entered the state of the machine is preserved on the system stack and a branch to the appropriate trap interrupt vector is made All trap and interrupt routines require the use of the RETI return from interrupt instruction to exit from the called routine This inst
199. e range of applications where serial data transfer is required The Data Width Selection supports the transfer of frames of any length from 2 bit characters up to 16 bit characters Starting with the LSB SSCHB 0 allows communication e g with ASCO devices in synchronous mode C166 family or 8051 like serial interfaces Starting with the MSB SSCHB 1 allows operation compatible with the SPI interface Regardless which data width is selected and whether the MSB or the LSB is transmitted first the transfer data is always right aligned in registers SSCTB and SSCRB with the LSB of the transfer data in bit 0 of these registers The data bits are rearranged for transfer by the internal shift register logic The unselected bits of SSCTB are ignored the unselected bits of SSCRB will be not valid and should be ignored by the receiver service routine The Clock Control allows the adaptation of transmit and receive behavior of the SSC to a variety of serial interfaces A specific clock edge rising or falling is used to shift out transmit data while the other clock edge is used to latch in receive data Bit SSCPH selects the leading edge or the trailing edge for each function Bit SSCPO selects the level of the clock line in the idle state So for an idle high clock the leading edge is a falling one a 1 to 0 transition The figure below is a summary Serial Clock SCLK uc co eseesene B s ONG
200. e regarded as one instruction in this sense e g MUL is one instruction Any instruction type can be used within an unseparable code sequence ATOMIC 3 The next 3 instr are locked No NOP requ MOV RO 1234H Instr 1 no other instr enters pipeline MOV R1 5678H Instr 2 MUL RO R1 Instr 3 MUL regarded as one instruction MOV R2 MDL This instruction is out of the scope PO Of the ATOMIC instruction sequence Semiconductor Group 20 12 1998 05 01 SIEMENS System Programming C161RI 20 9 Overriding the DPP Addressing Mechanism The standard mechanism to access data locations uses one of the four data page pointers DPPx which selects a 16 KByte data page and a 14 bit offset within this data page The four DPPs allow immediate access to up to 64 KByte of data In applications with big data arrays especially in HLL applications using large memory models this may require frequent reloading of the DPPs even for single accesses The EXTP extend page instruction allows switching to an arbitrary data page for 1 4 instructions without having to change the current DPPs EXTP R15 1 The override page number is stored in R15 MOV RO R14 The 14 bit page offset is stored in R14 MOV R1 R13 This instruction uses the std DPP scheme The EXTS extend segment instruction allows switching to a 64 KByte segment oriented data access scheme for 1 4 instructions without having to change the current DPPs In this ca
201. e than one interrupt request on a specific level gets active at the same time the values in the respective bit fields GLVL are used for second level arbitration to select one request for being serviced Again the group priority increases with the numerical value of GLVL so 00 is the lowest and 11g is the highest group priority Note All interrupt request sources that are enabled and programmed to the same priority level must always be programmed to different group priorities Otherwise an incorrect interrupt vector will be generated Semiconductor Group 5 6 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Upon entry into the interrupt service routine the priority level of the source that won the arbitration and who s priority level is higher than the current CPU level is copied into bit field ILVL of register PSW after pushing the old PSW contents on the stack The interrupt system of the C161RI allows nesting of up to 15 interrupt service routines of different priority levels level O cannot be arbitrated Interrupt requests that are programmed to priority levels 15 or 14 i e ILVL 111X will be serviced by the PEC unless the COUNT field of the associated PECC register contains zero In this case the request will instead be serviced by normal interrupt processing Interrupt requests that are programmed to priority levels 13 through 1 will always be serviced by normal interrupt processing Note Priority level 0000 is th
202. e there is no gap between the two successive frames E g two byte transfers would look the same as one word transfer This feature can be used to interface with devices which can operate with or require more than 16 data bits per transfer It is just a matter of software how long a total data frame length can be This option can also be used e g to interface to byte wide and word wide devices on the same serial bus Note Of course this can only happen in multiples of the selected basic data width since it would require disabling enabling of the SSC to reprogram the basic data width on the fly Semiconductor Group 12 9 1998 05 01 The High Speed Synchronous Serial Interface C161RI SIEMENS Port Control The SSC uses three pins of Port 3 to communicate with the external world Pin P3 13 SCLK serves as the clock line while pins P3 8 MRST Master Receive Slave Transmit and P3 9 MTSR Master Transmit Slave Receive serve as the serial data input output lines The operation of these pins depends on the selected operating mode master or slave In order to enable the alternate output functions of these pins instead of the general purpose IO operation the respective port latches have to be set to 1 since the port latch outputs and the alternate output lines are ANDed When an alternate data output line is not used function disabled it is held at a high level allowing IO operations via the port latch The direction of the port line
203. e transferred Semiconductor Group 11 7 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI 11 2 Synchronous Operation Synchronous mode supports half duplex communication basically for simple IO expansion via shift registers Data is transmitted and received via pin RXDO P3 11 while pin TXDO P3 10 outputs the shift clock These signals are alternate functions of Port 3 pins Synchronous mode is selected with SOM 000 8 data bits are transmitted or received synchronous to a shift clock generated by the internal baud rate generator The shift clock is only active as long as data bits are transmitted or received Reload Register z ED SOR SOM 000B Receive Int LA Request Serial Port Control SOTIR Tete TXDO P3 10 vile SONO Request Shift Clock Error Int BUR Request Receive i enis MUX Receive Shift Transmit Shift RXDO P3 1 1 Register Register Transmit Receive Buffer Reg Transmit Buffer Reg SORBUF SOTBUF d Internal Bus MCB02220 1 Figure 11 5 Synchronous Mode of Serial Channel ASCO Semiconductor Group 11 8 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Synchronous transmission begins within 4 state times after data has been loaded into SOTBUF provided that SOR is set and SOREN C half duplex no reception Data transmission is double buffered When the transmitter is idle the transmit data
204. ed and the first instructions are fetched from the internal memory Note Be sure not to select internal memory access after reset on ROMless devices Mapping the Internal ROM Area After reset the internal ROM area is mapped into segment 0 the system segment 00 0000 00 7FFF as a default This is necessary to allow the first instructions to be fetched from locations 00 0000 ff The ROM area may be mapped to segment 1 01 0000 01 7FFF by setting bit ROMS1 in register SYSCON The internal ROM area may now be accessed through the lower half of segment 1 while accesses to segment 0 will now be made to external memory This adds flexibility to the system software The interrupt trap vector table which uses locations 00 0000 through 00 01FF is now part of the external memory and may therefore be modified i e the system software may now change interrupt trap handlers according to the current condition of the system The internal code memory can still be used for fixed software routines like IO drivers math libraries application specific invariant routines tables etc This combines the advantage of an integrated non volatile memory with the advantage of a flexible adaptable software system Enabling and Disabling the Internal Code Memory After Reset If the internal code memory does not contain an appropriate startup code the system may be booted from external memory while the internal memory is enabled afterwards t
205. ed during this time Only one instruction will typically be executed if the first instruction following the RETI instruction is a branch instruction without cache hit or if it reads an operand from internal code memory or if it is executed out of the internal RAM Note A bus access in this context includes all delays which can occur during an external bus cycle Semiconductor Group 5 17 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI PEC Response Times The PEC response time defines the time from an interrupt request flag of an enabled interrupt source being set until the PEC data transfer being started The basic PEC response time for the C161RI is 2 instruction cycles Pipeline Stage Cycle 1 Cycle 2 Cycle 3 Cycle 4 FETCH N N 1 N 2 N 2 DECODE N 1 N PEC N 1 EXECUTE N 2 N 1 N PEC WRITEBACK N 3 N 2 N 1 N IR Flag PEC Response Time Figure 5 5 Pipeline Diagram for PEC Response Time In the figure above the respective interrupt request flag is set in cycle 1 fetching of instruction N The indicated source wins the prioritization round during cycle 2 In cycle 3 a PEC transfer instruction is injected into the decode stage of the pipeline suspending instruction N 1 and clearing the source s interrupt request flag to 0 Cycle 4 completes the injected PEC transfer and resumes the execution of instruction N 1 All instructions that entered the pipeline after se
206. egister SP FE12 09 CPU System Stack Pointer Register FC00 Semiconductor Group 21 6 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value SSCBR FOBA E 5A SSC Baudrate Register 0000 SSCCON b FFB2 D9 SSC Control Register 0000 SSCEIC b FF76 BB SSC Error Interrupt Control Register 0000 SSCRB FOB2 E 59 SSC Receive Buffer read only XXXXy SSCRIC _b FF74 BA SSC Receive Interrupt Control Register 0000 SSCTB FOBO E58 SSC Transmit Buffer write only 0000 SSCTIC b FF72 B9 SSC Transmit Interrupt Control Register 0000 STKOV FE14 0A CPU Stack Overflow Pointer Register FAOO STKUN FE16 0B CPU Stack Underflow Pointer Register FCOO SYSCON b FF12 89 CPU System Configuration Register 0XX0 SYSCON 2 b F1D0 E8 CPU System Configuration Register 2 0000 SYSCONS3 b F1D4 EA CPU System Configuration Register 3 0000 T14 FOD2 E69 RTC Timer 14 Register no T14REL FODO E68 RTC Timer 14 Reload Register no T2 FE40 20 GPT1 Timer 2 Register 0000 T2CON b FF40 A0 GPT1 Timer 2 Control Register 0000 T2lC b FF60 B0 GPT1 Timer 2 Interrupt Control Register 0000 T3 FE42 21 GPT1 Timer 3 Register 0000 T3CON b FF42 Aly GPT1 Timer 3 Control Register 0000 T3IC b FF62 B1 GPT1 Timer 3 Interrupt Control Register 0000 T4 FE44 22 GPT1 Timer 4
207. egisters The source and destination pointers for the peripheral event controller are mapped to a special area within the internal RAM Pointers that are not occupied by the PEC may therefore be used like normal RAM During Power Down mode or any warm reset the PEC pointers are preserved The PEC and its registers are described in chapter Interrupt and Trap Functions GPR Access in the ESFR Area The locations 00 FOOOH 00 FO01EH within the ESFR area are reserved and allow to access the current register bank via short register addressing modes The GPRs are mirrored to the ESFR area which allows access to the current register bank even after switching register spaces see example below MOV R5 DP3 GPR access via SFR area EXTR 1 MOV R5 ODP3 GPR access via ESFR area Writing Bytes to SFRs All special function registers may be accessed wordwise or bytewise some of them even bitwise Reading bytes from word SFRs is a non critical operation However when writing bytes to word SFRs the complementary byte of the respective SFR is cleared with the write operation Semiconductor Group 21 14 1998 05 01 SIEMENS Instruction Set Summary C161RI 22 Instruction Set Summary This chapter briefly summarizes the C161RIl s instructions ordered by instruction classes This provides a basic understanding of the C161Hl s instruction set the power and versatility of the instructions and their general usage A detailed description of
208. elected so the IC module can communicate with standard 7 bit devices as well as with more sophisticated 10 bit devices 100 KBd or 400 KBd transfer speed can be selected so the IC module can communicate with slow devices conforming to the standard I C bus specification as well as with fast devices conforming to the extended specification Physical channels can be selected so the FC module can use electrically separated channels or increase the addressing range by using more data lines Note Baudrate and physical channels should never be changed via ICCFG during a transfer Operation in Master Mode If the on chip FC module shall control the FC bus i e be bus master master mode must be selected via bitfield MOD in register ICCON The physical channel is configured by a control word written to register ICCFG defining the active interface pins and the used baudrate More than one SDA and or SCL line may be active at a time The address of the remote slave that is to be accessed is written to ICRTB The bus is claimed by setting bit BUM in register ICCON This generates a start condition on the bus and automatically starts the transmission of the address in ICRTB Bit TRX in register ICCON defines the transfer direction TRX 2 1 i e transmit for the slave address A repeated start condition is generated by setting bit RSC in register ICCON which automatically starts the transmission of the address previously written to ICRTB This may be
209. emories or peripherals is supported via a particular Ready function For applications which require less than 64 KBytes of address space a non segmented memory model can be selected where all locations can be addressed by 16 bits and thus Port 4 is not needed as an output for the upper address bits Axx A16 as is the case when using the segmented memory model The on chip XBUS is an internal representation of the external bus and allows to access integrated application specific peripherals modules in the same way as external components It provides a defined interface for these customized peripherals The on chip XRAM and the on chip I C Module are examples for these X Peripherals Semiconductor Group 2 8 1998 05 01 SIEMENS Architectural Overview C161RI 2 3 The On chip Peripheral Blocks The C166 family clearly separates peripherals from the core This structure permits the maximum number of operations to be performed in parallel and allows peripherals to be added or deleted from family members without modifications to the core Each functional block processes data independently and communicates information over common buses Peripherals are controlled by data written to the respective Special Function Registers SFRs These SFRs are located either within the standard SFR area 00 FEO00 O0 FFFF or within the extended ESFR area 00 F000 O0 F1FF These built in peripherals either allow the CPU to interface with t
210. en changing the content of a DPP register if a non segmented memory model is selected because otherwise unexpected results could occur In case of the segmented memory mode the selected number of segment address bits via bitfield SALSEL of the respective DPP register is output on the respective segment address pins of Port 4 for all external data accesses A DPP register can be updated via any instruction which is capable of modifying an SFR Note Due to the internal instruction pipeline a new DPP value is not yet usable for the operand address calculation of the instruction immediately following the instruction updating the DPP register Data Pages 6 Bit Data Address 15 14 0 1023 3 1022 1021 x DPP Registers v 3 DPP3 11 14 Bi Intra Page Address 2 jt DPP2 10 Concatenated with 4 DPP4 041 content of DPPx 0 4 DPP0 0 0 MCA02264 After reset or with segmentation disabled the DPP registers select data pages 3 0 All of the internal memory is accessible in these cases Figure 4 6 Addressing via the Data Page Pointers Semiconductor Group 4 21 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Context Pointer CP This non bit addressable register is used to select the current register context This means that the CP register value determines the address of the
211. ence INT ON BSET IEN globally re enable interrupts Note The described delay of 1 instruction also applies for enabling the interrupts system i e no interrupt requests are acknowledged until the instruction following the enabling instruction e Initialization of Port Pins Modifications of the direction of port pins input or output become effective only after the instruction following the modifying instruction As bit instructions BSET BCLR use internal read modify write sequences accessing the whole port instructions modifying the port direction should be followed by an instruction that does not access the same port see example below PORT INIT WRONG BSET DP3 13 change direction of P3 13 to output BSET P3 9 P3 13 is still input rd mod wr reads pin P3 13 PORT INIT RIGHT BSET DP3 13 change direction of P3 13 to output NOP any instruction not accessing port 3 BSET P3 9 P3 13 is now output rd mod wr reads P3 13 s output latch Semiconductor Group 4 7 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI e Changing the System Configuration The instruction following an instruction that changes the system configuration via register S YSCON e g the mapping of the internal ROM segmentation stack size cannot use the new resources e g ROM or stack In these cases an instruction that does not access these resources should be inserted Code accesses to the new ROM area are only possible after an absol
212. ently running on basic clock frequ Switch Unlock Unlock Unlock Single to ESFR space and lock sequence sequence step 1 1001B sequence step 2 0011B sequence step 3 0111B access to SYSCON2 SYSCON3 CLKCON 01B SDD frequency Currently running on SDD frequency Switch Unlock Unlock Unlock Single to ESFR space and lock sequence sequence step 1 1001B sequence step 2 0011B sequence step 3 0111B access to SYSCON2 SYSCON3 CLKCON 00B basic frequency 19 13 1998 05 01 SIEMENS System Programming C161RI 20 System Programming To aid in software development a number of features has been incorporated into the instruction set of the C161Rl including constructs for modularity loops and context switching In many cases commonly used instruction sequences have been simplified while providing greater flexibility The following programming features help to fully utilize this instruction set Instructions Provided as Subsets of Instructions In many cases instructions found in other microcontrollers are provided as subsets of more powerful instructions in the C161RI This allows the same functionality to be provided while decreasing the hardware required and decreasing decode complexity In order to aid assembly programming these instructions familiar from other microcontrollers can be built in macros thus providing the same names Directly Substitutable Instructions ar
213. ents Control Registers Data Registers Counter Registers Interrupt Control SYSCON2 E TIABED E SYSCON2 Power Management Control Register RTCH Real Time Clock Register High Word T14REL Timer T14 Reload Register RTCL Real Time Clock Register Low Word T14 Timer T14 Count Register ISNC Interrupt Subnode Control Register XP3IC RTC Interrupt Control Register Figure 14 1 SFRs Associated with the RTC Module The RTC module consists of a chain of 3 divider blocks a fixed 8 1 divider the reloadable 16 bit timer T14 and the 32 bit RTC timer accessible via registers RTCH and RTCL Both timers count up The clock signal for the RTC module is directly derived from the on chip oscillator frequency not from the CPU clock and fed through a separate clock driver It is therefore independent from the selected clock generation mode of the C161RI and is controlled by the clock generation circuitry RTC Register Location within the ESFR Space Register Name Long Short Address Reset Value Notes T14 FOD2 69 UUUU Prescaler timer generates input clock for RTC register and periodic interrupt T14REL FODO 68 UUUU Timer reload register RTCH FOD6 6B UUUU High word of RTC register RTCL FOD4 6A UUUU Low word of RTC register Note The RTC registers are not affected by a reset After a power on reset however they are undefined Semiconductor Group 14 1 1998 06 01 SIEMENS The Real Ti
214. eral Purpose Timer Units C161RI Timer 3 in Timer Mode Timer mode for the core timer T3 is selected by setting bit field T3M in register T3CON to 000 In this mode T3 is clocked with the internal system clock CPU clock divided by a programmable prescaler which is selected by bit field T3I The input frequency fr for timer T3 and its resolution rys are scaled linearly with lower clock frequencies fopy as can be seen from the following formula foru 8x 9 lt T3l gt ee rs us Basse i foru MHz CPU Interrupt Geek 58 H eu Up TxR Tx3UD Down TxOTL I TxOUT i ee MUX TxOE TEUD l EXOR T3EUD P3 4 TXUDE x 3 T30UT P3 3 MCB03907 Figure 10 3 Block Diagram of Core Timer T3 in Timer Mode The timer input frequencies resolution and periods which result from the selected prescaler option are listed in the table below This table also applies to the Gated Timer Mode of T3 and to the auxiliary timers T2 and T4 in timer and gated timer mode Note that some numbers may be rounded to 3 significant digits GPT1 Timer Input Frequencies Resolution and Periods fcpy 20 MHz Timer Input Selection T2l T3I T4I 000 001 010 O11 100 101 110 111 Prescaler factor 8 16 32 64 128 256 512 1024 Input Frequency 2 5 1 25 625 312 5 156 25 78 125 39 06 119 53 MHz MHz kHz kHz kHz kHz kHz kHz Resolution 400ns 800ns 1 6us 3 2us 6 4us 12 8 us 25 6
215. eral in many cases is represented by just a few registers the registers partly select smaller address windows than the standard ADDRSEL registers As the register pairs control integrated peripherals rather than externally connected ones they are fixed by mask programming rather than being user programmable X Peripheral accesses provide the same choices as external accesses so these peripherals may be bytewide or wordwide with or without a separate address bus Interrupt nodes are provided for X Peripherals to be integrated Note If you plan to develop a peripheral of your own to be integrated into a C161RI device to create a customer specific version please ask for the specification of the XBUS interface and for further support Semiconductor Group 9 26 1998 06 01 SIEMENS The General Purpose Timer Units C161RI 10 The General Purpose Timer Units The General Purpose Timer Units GPT1 and GPT2 represent very flexible multifunctional timer structures which may be used for timing event counting pulse width measurement pulse generation frequency multiplication and other purposes They incorporate five 16 bit timers that are grouped into the two timer blocks GPT1 and GPT2 Block GPT1 contains 3 timers counters with a maximum resolution of 16 TCL while block GPT2 contains 2 timers counters with a maximum resolution of 8 TCL and a 16 bit Capture Reload register CAPREL Each timer in each block may operate independently in a number of
216. erent configurations T3 can operate in timer gated timer or counter mode in this case Tyl Interrupt we Request Core Timer Ty TyR Up Down Edge Select m Interrupt re Auxiliary Timer Tx Timer Auxiliary Timer Tx TxIR Request Line only affected by over underflows of T3 but NOT by software modifications of T3OTL MCB02034 T3OUT P33 X22 y 3 Figure 10 11 Concatenation of Core Timer T3 and an Auxiliary Timer Semiconductor Group 10 14 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Auxiliary Timer in Reload Mode Reload mode for the auxiliary timers T2 and T4 is selected by setting bit field TxM in the respective register TXCON to 100 In reload mode the core timer T3 is reloaded with the contents of an auxiliary timer register triggered by one of two different signals The trigger signal is selected the same way as the clock source for counter mode see table above i e a transition of the auxiliary timer s input or the output toggle latch T3OTL may trigger the reload Note When programmed for reload mode the respective auxiliary timer T2 or T4 stops independent of its run flag T2R or T4R Source Edge Select Reload Register Tx TxIN Interrupt e37Pas L 1 p i rr Request li BA Tx Input rnr Interrupt Clocks 0 Core Timer T3 T3IR Request Up Down T30TL X 2 4 3 Line only affected by over underflows of T3 b
217. eserved 0 1 0 Reserved 1 fix 1to 20 MHz Direct drive 0 1 0 Reserved feral 2 2 to 40 MHz Prescaler operation OIOI Oo OF SY o oO o o Reserved The maximum depends on the duty cycle of the external clock signal In emulation mode pin P0 15 POH 7 is inverted i e the configuration 111 would select direct drive in emulation mode Default Reserved combination Select a valid configuration in any case Note Watch the different requirements for frequency and duty cycle of the oscillator input clock for the possible selections Semiconductor Group 18 13 1998 06 01 SIEMENS Power Management C161RI 19 Power Management For an increasing number of microcontroller based systems it is an important objective to reduce the power consumption of the system as much as possible A contradictory objective is however to reach a certain level of system performance Besides optimization of design and technology a microcontroller s power consumption can generally be reduced by lowering its operating frequency and or by reducing the circuitry that is clocked The architecture of the C161RI provides three major means of reducing its power consumption see figure below under software control Reduction of the CPU frequency for Slow Down operation Flexible Clock Gen Management Selection of the active peripheral modules Flexible Peripheral Management Special ope
218. ess the mode selection field ADM and the channel selection field ADCH may be changed These bitfields will be evaluated after the current conversion Fixed Channel Conversion Modes These modes are selected by programming the mode selection bitfield ADM in register ADCON to 0 single conversion or to 1 continuous conversion After starting the converter through bit ADST the busy flag ADBSY will be set and the channel specified in bit field ADCH will be converted After the conversion is complete the interrupt request flag ADCIR will be set In Single Conversion Mode the converter will automatically stop and reset bits ADBSY and ADST In Continuous Conversion Mode the converter will automatically start a new conversion of the channel specified in ADCH ADCIR will be set after each completed conversion When bit ADST is reset by software while a conversion is in progress the converter will complete the current conversion and then stop and reset bit ADBSY Semiconductor Group 16 4 1998 05 01 SIEMENS The Analog Digital Converter C161RI 16 2 Conversion Timing Control When a conversion is started first the capacitances of the converter are loaded via the respective analog input pin to the current analog input voltage The time to load the capacitances is referred to as sample time Next the sampled voltage is converted to a digital value in successive steps which correspond to the resolution of the ADC During these ph
219. ess 21 9 sorted by name 21 4 Reset 10 11 18 1 Bidirectional 18 3 Configuration 18 6 Output 18 5 Source indication 13 4 Values 18 5 ROM Handling 20 14 RPOH 9 24 RTC 2 13 14 1 S SOBG 11 10 SOCON 11 2 SOEIC SORIC SOTIC SOTBIC 11 12 SORBUF 11 7 11 9 SOTBUF 11 6 11 9 Security Mechanism 19 12 Segment Address 9 8 18 12 boundaries 3 11 Segmentation 4 18 Enable Disable 4 13 Serial Interface 2 11 11 1 Asynchronous 11 4 CAN 2 11 Synchronous 11 8 12 1 SFR 3 8 21 4 21 9 Single Chip Mode 9 2 Slave mode lC Bus 17 7 Slow Down Mode 19 7 Software Reset 18 1 Traps 5 24 Source Interrupt 5 3 Reset 13 4 SP 4 24 Special operation modes config 18 10 Semiconductor Group SSC 12 1 Baudrate generation 12 10 Error Detection 12 12 Full Duplex 12 6 Half Duplex 12 8 SSCBR 12 10 SSCCON 12 2 SSCEIC SSCRIC SSCTIC 12 14 SSCRB SSCTB 12 7 Stack 3 5 4 24 20 4 Startup Configuration 18 6 STKOV 4 25 STKUN 4 26 Subroutine 20 9 Synchronous Serial Interface gt SSC 12 1 SYSCON 4 11 9 17 SYSCON2 19 8 SYSCONS 19 11 T T2CON 10 11 T21C T3IC TAIC 10 18 T3CON 10 3 T4CON 10 11 T5CON 10 23 T5IC T6IC 10 29 T6CON 10 21 TFR 5 25 Threshold 7 3 Timer 2 12 10 1 10 19 Auxiliary Timer 10 11 10 23 Concatenation 10 14 10 25 Core Timer 10 3 10 21 Tools 1 6 Traps 5 4 5 24 Tri State Time 9 13 U Unlock Sequence 19 12 Unseparable instructions 20 12 W Waitstate Memory Cycle 9 12 Tri State 9 13 Wat
220. et Value 00 7 6 5 4 3 2 1 0 woes um o ma rw rw rw rw SOTBIC F19C CE ESFR Reset Value 00 1 14 14 1e 11 10 9 8 7 5 4 3 2 1 0 TBIR TBIE ILVL GLVL rw rw rw rw Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Semiconductor Group 11 12 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Using the ASCO Interrupts For normal operation i e besides the error interrupt the ASCO provides three interrupt requests to control data exchange via this serial channel SOTBIR is activated when data is moved from SOTBUF to the transmit shift register SOTIR is activated before the last bit of an asynchronous frame is transmitted or after the last bit of a synchronous frame has been transmitted SORIR is activated when the received frame is moved to SORBUF While the task of the receive interrupt handler is quite clear the transmitter is serviced by two interrupt handlers This provides advantages for the servicing software For single transfers is sufficient to use the transmitter interrupt SOTIR which indicates that the previously loaded data has been transmitted except for the last bit of an asynchronous frame For multiple back to back transfers it is necessary to load the following piece of data at last until the time the last bit of the previous frame has been transmitted In asynchr
221. etched IP refers to the current segment lt SEGNR gt Semiconductor Group 4 17 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Code Segment Pointer CSP This non bit addressable register selects the code segment being used at run time to access instructions The lower 8 bits of register CSP select one of up to 256 segments of 64 KBytes each while the upper 8 bits are reserved for future use CSP FEO08 04 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Bit Function SEGNR Segment Number Specifies the code segment from where the current instruction is to be fetched SEGNR is ignored when segmentation is disabled Code memory addresses are generated by directly extending the 16 bit contents of the IP register by the contents of the CSP register as shown in the figure below In case of the segmented memory mode the selected number of segment address bits via bitfield SALSEL of register CSP is output on the respective segment address pins of Port 4 for all external code accesses For non segmented memory mode or Single Chip Mode the content of this register is not significant because all code acccesses are automatically restricted to segment 0 Note The CSP register can only be read but not written by data operations It is however modified either directly by means of the JMPS and CALLS instructions or indirectly via the stack by means of the RETS and RETI instructions
222. fied in the operand field of the trap instruction determines which vector location in the address range from 00 0000 through 00 01FC will be branched to Executing a TRAP instruction causes a similar effect as if an interrupt at the same vector had occurred PSW CSP in segmentation mode and IP are pushed on the internal system stack and a jump is taken to the specified vector location When segmentation is enabled and a trap is executed the CSP for the trap service routine is set to code segment 0 No Interrupt Request flags are affected by the TRAP instruction The interrupt service routine called by a TRAP instruction must be terminated with a RETI return from interrupt instruction to ensure correct operation Note The CPU level in register PSW is not modified by the TRAP instruction so the service routine is executed on the same priority level from which it was invoked Therefore the service routine entered by the TRAP instruction can be interrupted by other traps or higher priority interrupts other than when triggered by a hardware trap Hardware Traps Hardware traps are issued by faults or specific system states that occur during runtime of a program not identified at assembly time A hardware trap may also be triggered intentionally e g to emulate additional instructions by generating an Illegal Opcode trap The C161RI distinguishes eight different hardware trap functions When a hardware trap condition has been detected the
223. fined SYSCON 0XXO0 set according to reset configuration BUSCONO O0XXO set according to reset configuration RPOH XX reset levels of POH ONES FFFF fixed value Semiconductor Group 18 5 1998 06 01 SIEMENS System Reset C161RI The Internal RAM after Reset The contents of the internal RAM are not affected by a system reset However after a power on reset the contents of the internal RAM are undefined This implies that the GPRs R15 RO and the PEC source and destination pointers SRCP7 SRCPO DSTP7 DSTPO which are mapped into the internal RAM are also unchanged after a warm reset software reset or watchdog reset but are undefined after a power on reset Ports and External Bus Configuration during Reset During the internal reset sequence all of the C161RI s port pins are configured as inputs by clearing the associated direction registers and their pin drivers are switched to the high impedance state This ensures that the C161RI and external devices will not try to drive the same pin to different levels Pin ALE is held low through an internal pulldown and pins RD WR and READY are held high through internal pullups Also the pins selected for CS output will be pulled high The registers SYSCON and BUSCONO are initialized according to the configuration selected via PORTO When an external start is selected pin EA 0 the Bus Type field BTYP in register BUSCONO is initialized according to
224. first General Purpose Register GPR within the current register bank of up to 16 wordwide and or bytewide GPRs CP FE10 08 SFR Reset Value FC00 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 r r r r rw r Bit Function cp Modifiable portion of register CP Specifies the word base address of the current register bank When writing a value to register CP with bits CP 11 CP 9 000 bits CP 11 CP 10 are set to 11 by hardware in all other cases all bits of bit field cp receive the written value Note It is the user s responsibility that the physical GPR address specified via CP register plus short GPR address must always be an internal RAM location If this condition is not met unexpected results may occur Do not set CP below the IRAM start address i e 00 FA00 00 F600 00 F200 1 2 3KB Do not set CP above 00 FDFE e Be careful using the upper GPRs with CP above 00 FDEO The CP register can be updated via any instruction which is capable of modifying an SFR Note Due to the internal instruction pipeline a new CP value is not yet usable for GPR address calculations of the instruction immediately following the instruction updating the CP register The Switch Context instruction SCXT allows to save the content of register CP on the stack and updating it with a new value in just one machine cycle Semiconductor Group 4 22 1998 05 01 SIEMENS The Central Processing Unit CPU C161R
225. formance compared to instructions directly supporting BCD data types while no additional hardware is required Semiconductor Group 20 3 1998 05 01 SIEMENS System Programming C161RI 20 1 Stack Operations The C161RI supports two types of stacks The system stack is used implicitly by the controller and is located in the internal RAM The user stack provides stack access to the user in either the internal or external memory Both stack types grow from high memory addresses to low memory addresses Internal System Stack A system stack is provided to store return vectors segment pointers and processor status for procedures and interrupt routines A system register SP points to the top of the stack This pointer is decremented when data is pushed onto the stack and incremented when data is popped The internal system stack can also be used to temporarily store data or pass it between subroutines or tasks Instructions are provided to push or pop registers on from the system stack However in most cases the register banking scheme provides the best performance for passing data between multiple tasks Note The system stack allows the storage of words only Bytes must either be converted to words or the respective other byte must be disregarded Register SP can only be loaded with even byte addresses The LSB of SP is always 0 Detection of stack overflow underflow is supported by two registers STKOV Stack Overflow Pointer an
226. from internal memory or by explicitly addressing the SFRs associated with the specific peripherals After resetting the C161RI all peripherals except the watchdog timer are disabled and initialized to default values A desired configuration of a specific peripheral is programmed using MOV instructions of either constants or memory values to specific SFRs Specific control flags may also be altered via bit instructions Once in operation the peripheral operates autonomously until an end condition is reached at which time it requests a PEC transfer or requests CPU servicing through an interrupt routine Information may also be polled from peripherals through read accesses to SFRs or bit operations including branch tests on specific control bits in SFRs To ensure proper allocation of peripherals among multiple tasks a portion of the internal memory has been made bit addressable to allow user semaphores Instructions have also been provided to lock out tasks via software by setting or clearing user specific bits and conditionally branching based on these specific bits It is recommended that bit fields in control SFRs are updated using the BFLDH and BFLDL instructions or a MOV instruction to avoid undesired intermediate modes of operation which can occur when BCLR BSET or AND OR instruction sequences are used Semiconductor Group 20 11 1998 05 01 SIEMENS System Programming C161RI 20 6 Floating Point Support All floating point operations ar
227. ftware will NOT trigger the counter function of T2 T4 Semiconductor Group 10 13 1998 05 01 SIEMENS The General Purpose Timer Units C161RI For counter operation pin TxIN must be configured as input i e the respective direction control bit must be 0 The maximum input frequency which is allowed in counter mode is fcpy 16 To ensure that a transition of the count input signal which is applied to TxIN is correctly recognized its level should be held for at least 8 f pj cycles before it changes Timer Concatenation Using the toggle bit T3OTL as a clock source for an auxiliary timer in counter mode concatenates the core timer T3 with the respective auxiliary timer Depending on which transition of T3OTL is selected to clock the auxiliary timer this concatenation forms a 32 bit or a 33 bit timer counter 32 bit Timer Counter If both a positive and a negative transition of TSOTL is used to clock the auxiliary timer this timer is clocked on every overflow underflow of the core timer T3 Thus the two timers form a 32 bit timer 33 bit Timer Counter If either a positive or a negative transition of TSOTL is selected to clock the auxiliary timer this timer is clocked on every second overflow underflow of the core timer T3 This configuration forms a 33 bit timer 16 bit core timer T30TL 16 bit auxiliary timer The count directions of the two concatenated timers are not required to be the same This offers a wide variety of diff
228. g Semiconductor Group 4 5 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Particular Pipeline Effects Since up to four different instructions are processed simultaneously additional hardware has been spent in the C161RI to consider all causal dependencies which may exist on instructions in different pipeline stages without a loss of performance This extra hardware i e for forwarding operand read and write values resolves most of the possible conflicts e g multiple usage of buses in a time optimized way and thus avoids that the pipeline becomes noticeable for the user in most cases However there are some very rare cases where the circumstance that the C161RI is a pipelined machine requires attention by the programmer In these cases the delays caused by pipeline conflicts can be used for other instructions in order to optimize performance Context Pointer Updating An instruction which calculates a physical GPR operand address via the CP register is mostly not capable of using a new CP value which is to be updated by an immediately preceding instruction Thus to make sure that the new CP value is used at least one instruction must be inserted between a CP changing and a subsequent GPR using instruction as shown in the following example ln SCXT CP 40FCOOh select a new context Iani V cs must not be an instruction using a GPR l2 MOV RO dataX write to GPR 0 in the new context e Data Page Poin
229. g a hardware triggered reset sequence The pins that influence the configuration of the C161RI are evaluated during any reset sequence i e also during software and watchdog timer triggered resets The configuration via POH is latched in register RPOH for subsequent evaluation by software Register RPOH is described in chapter The External Bus Interface Note The load on those pins that shall be latched as 1 must be small enough for the internal pullup device to keep their level high or external pullup devices must ensure the high level Those pins that shall be latched as 0 must be pulled low externally Make sure that the valid target levels are reached until the end of the reset sequence There is a specific application note to illustrate this The following describes the different selections that are offered for reset configuration The default modes refer to pins at high level i e without external pulldown devices connected Please also consider the note above Emulation Mode Pin POL O EMU selects the Emulation Mode when low during reset This mode allows the access to integrated XBUS peripherals via the external bus interface pins in application specific versions of the C161RI In addition also the RSTOUT pin floats to tristate rather than be driven low When the emulation mode has been latched the CLKOUT output is automatically enabled This mode is used for special emulator purposes and is of no use in basic C161RI devi
230. g to the transmit buffer ICRTB Semiconductor Group 17 9 1998 05 01 2 SIEMENS The I2C Bus Module C161RI ICST ED04 XReg Reset Value 000X 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 z s E rw rw r r r rw r Bit Function ADR Address Bit ADR is set after a start condition in slave mode until the address has been received 1 byte in 7 bit address mode 2 bytes in 10 bit address mode AL Arbitration Lost Bit AL is set when the C module has tried to become master on the bus but has lost the arbitration Operation is continued until the 9th clock pulse Bit IRQP is set along with bit AL Bit AL must be cleared via software SLA Slave 0 The FC bus is not busy or the module is in master mode 1 The FC module has been selected as a slave device address received LRB Last Received Bit undefined after reset Bit LRB represents the last bit ie the acknowledge bit of the last transmitted or received frame BB Bus Busy 0 The FC bus is idle ie a stop condition has occurred 1 The PC bus is active ie a start condition has occurred Note Bit BB is always 0 while the PC module is disabled IRQD EC Interrupt Request Bit for Data Transfer Events 0 No interrupt request pending 1 A data transfer event interrupt request is pending IRQD is set after the acknowledge bit of a byte has been received or transmitted and is cleared automatically upon a read or write access to the buffer ICR
231. given application system Ports amp Direction Control Address Registers Mode Registers Control Registers Alternate Functions POL POH P1L P1H BUSCONO SYSCON BUSCON1 RPOH BUSCON2 ADDRSEL1 ADDRSEL2 ADDRSEL3 ADDRSEL4 ODP6 E PORTO EA BUSCON3 BUSCON4 PORT1 RSTIN M 2 WR WRL BHE WRH POL POH PORTO Data Registers ADDRSELx Address Range Select Register 1 4 P1L P1H PORT1 Data Registers BUSCONx Bus Mode Control Register O 4 DP3 Port 3 Direction Control Register SYSCON System Control Register P3 Port 3 Data Register RPOH Port POH Reset Configuration Register P4 Port 4 Data Register ODP6 Port 6 Open Drain Control Register DP6 Port 6 Direction Control Register P6 Port 6 Data Register Figure 9 1 SFRs and Port Pins Associated with the External Bus Interface Accesses to external memory or peripherals are executed by the integrated External Bus Controller EBC The function of the EBC is controlled via the SYSCON register and the BUSCONx and ADDRSELx registers The BUSCONXx registers specify the external bus cycles in terms of data width 16 bit 8 bit chip selects and length waitstates ALE RW delay These parameters are used for accesses within a specific address area which is defined via the corresponding register ADDRSELx The four pairs BUSCON1 ADDRSEL1 BUSCON4 ADDRSEL4 allow to define four independent address windows while all external accesses outside these windows are controlled via register
232. he NMI and the UNDOPC flag is set the IP of the instruction with the undefined opcode is pushed onto the system stack but the NMI trap is executed After return from the NMI service routine the IP is popped from the stack and immediately pushed again because of the pending UNDOPC trap External NMI Trap Whenever a high to low transition on the dedicated external NMI pin Non Maskable Interrupt is detected the NMI flag in register TFR is set and the CPU will enter the NMI trap routine The IP value pushed on the system stack is the address of the instruction following the one after which normal processing was interrupted by the NMI trap Note The NMI pin is sampled with every CPU clock cycle to detect transitions Stack Overflow Trap Whenever the stack pointer is decremented to a value which is less than the value in the stack overflow register STKOV the STKOF flag in register TFR is set and the CPU will enter the stack overflow trap routine Which IP value will be pushed onto the system stack depends on which operation caused the decrement of the SP When an implicit decrement of the SP is made through a PUSH or CALL instruction or upon interrupt or trap entry the IP value pushed is the address of the following instruction When the SP is decremented by a subtract instruction the IP value pushed represents the address of the instruction after the instruction following the subtract instruction For recovery from stack overflow it must be
233. he XRAM is 00 E7FE For PEC data transfers the XRAM can be accessed independent of the contents of the DPP registers via the PEC source and destination pointers Note As the XRAM appears like external memory it cannot be used for the C161RI s system stack or register banks The XRAM is not provided for single bit storage and therefore is not bit addressable The on chip XRAM is accessed without any waitstates using 16 bit demultiplexed bus cycles which take 125 ns 16 MHz fcpy Even if the XRAM is used like external memory it does not occupy BUSCONX ADDRSELx registers but rather is selected via additional dedicated XBCON XADRS registers These registers are mask programmed and are not user accessible With these registers the address area 00 E000 to 00 E7FF is reserved for XRAM accesses XRAM Access via External Masters When bit XPER SHARE in register SYSCON is set the on chip XRAM of the C161RI can be accessed by an external master during hold mode via the C161RI s bus interface These external accesses must use the same configuration as internally programmed ie demultiplexed bus 125 ns minimum access cycle time No waitstates are required Note The configuration in register SYSCON cannot be changed after the execution of the EINIT instruction Semiconductor Group 3 9 1998 05 01 SIEMENS Memory Organization C161RI 3 4 External Memory Space The C161RI is capable of using an address space of up to 16 MByte Only p
234. he external world or provide functions on chip that otherwise were to be added externally in the respective system The C161RI generic peripherals are Two General Purpose Timer Blocks GPT1 and GPT2 Two Serial Interfaces ASCO and SSC A Watchdog Timer An 8 bit Analog Digital Converter A Real Time Clock Seven IO ports with a total of 76 IO lines Each peripheral also contains a set of Special Function Registers SFRs which control the functionality of the peripheral and temporarily store intermediate data results Each peripheral has an associated set of status flags Individually selected clock signals are generated for each peripheral from binary multiples of the CPU clock Peripheral Interfaces The on chip peripherals generally have two different types of interfaces an interface to the CPU and an interface to external hardware Communication between CPU and peripherals is performed through Special Function Registers SFRs and interrupts The SFRs serve as control status and data registers for the peripherals Interrupt requests are generated by the peripherals based on specific events which occur during their operation e g operation complete error etc For interfacing with external hardware specific pins of the parallel ports are used when an input or output function has been selected for a peripheral During this time the port pins are controlled by the peripheral when used as outputs or by the external h
235. he following enhancements have been included to allow processing of a large number of interrupt sources 1 Peripheral Event Controller PEC This processor is used to off load many interrupt requests from the CPU It avoids the overhead of entering and exiting interrupt or trap routines by per forming single cycle interrupt driven byte or word data transfers between any two locations in segment 0 with an optional increment of either the PEC source or the destination pointer Just one cycle is stolen from the current CPU activity to perform a PEC service 2 Multiple Priority Interrupt Controller This controller allows all interrupts to be placed at any specified priority Interrupts may also be grouped which provides the user with the ability to prevent similar priority tasks from interrupting each other For each of the possible interrupt sources there is a separate control register which contains an interrupt request flag an inter rupt enable flag and an interrupt priority bitfield Once having been accepted by the CPU an interrupt service can only be interrupted by a higher prioritized service request For standard interrupt processing each of the possible interrupt sources has a dedicated vector location 3 Multiple Register Banks This feature allows the user to specify up to sixteen general pur pose registers located anywhere in the internal RAM A single one machine cycle instruction allows to switch register banks from one task
236. he peripheral clock driver PCD the following details should be respected The clock signal for all connected peripherals is stopped Make sure that all peripherals enter a safe state before disabling PCD The output signal CLKOUT will remain high 1 e Interrupt requests will still be recognized even while PCD is disabled No new output values are gated from the port output latches to the output port pins and no new input values are latched from the input port pins Semiconductor Group 19 11 1998 05 01 SIEMENS Power Management C161RI Security Mechanism The power management control registers SYSCON2 and SYSCONS control functions and modes which are critical for the C161Rl s operation For this reason they are locked except for bitfield SYSRLS in register SYSCON2 after the execution of EINIT like register SYSCON so these vital system functions cannot be changed inadvertently e g by software errors However as these registers control the power management they need to be accessed during operation to select the appropriate mode The system control software gets this access via a special unlock sequence which allows one single write access to either SYSCON2 or SYSCONS when executed properly This provides a maximum of security Note Of course SYSCON2 and SYSCON3 may be read at any time without restrictions The unlock sequence is executed by writing defined values to bitfield SYSRLS using defined instructions see tabl
237. he same interrupt priority ILVL and assigning a dedicated group level GLVL to each member This functionality is built in and handled automatically by the interrupt controller Classes with more than 4 members can be established by using a number of adjacent interrupt priorities ILVL and the respective group levels 4 per ILVL Each interrupt service routine within this class sets the CPU level to the highest interrupt priority within the class All requests from the same or any lower level are blocked now i e no request of this class will be accepted The example below establishes 3 interrupt classes which cover 2 or 3 interrupt priorities depending on the number of members in a class A level 6 interrupt disables all other sources in class 2 by changing the current CPU level to 8 which is the highest priority IL VL in class 2 Class 1 requests or PEC requests are still serviced in this case The 24 interrupt sources excluding PEC requests are so assigned to 3 classes of priority rather than to 7 different levels as the hardware support would do Semiconductor Group 5 13 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Software controlled Interrupt Classes Example ILVL GLVL Interpretation Priority 3l2l1lo 15 PEC service on up to 8 channels 14 13 12 X X X X Interrupt Class 1 11 X 5 sources on 2 levels 10 9 8 X X X X Interrupt Class
238. he system architecture the required address space is chosen and accessible right from the start so the initialization routine can directly access all locations without prior programming The required pins of Port 4 are automatically switched to address output mode SALSEL Segment Address Lines Directly accessible Address Space 11 Two A17 A16 256 KByte Default without pull downs 10 Seven A22 A16 8 MByte Maximum 0 1 None 64 KByte Minimum 00 Four A19 A16 1 MByte Even if not all segment address lines are enabled on Port 4 the C161RI internally uses its complete 24 bit addressing mechanism This allows the restriction of the width of the effective address bus while still deriving CS signals from the complete addresses Default 2 bit segment address A17 A16 allowing access to 256 KByte Note The selected number of segment address lines cannot be changed via software after reset Semiconductor Group 18 12 1998 06 01 SIEMENS System Reset C161RI Clock Generation Control Pins POH 7 POH 6 and POH 5 CLKCFG select the basic clock generation mode during reset The oscillator clock either directly feeds the CPU and peripherals direct drive or it is divided by 2 These bits are latched in register RPOH C161RI Clock Generation Modes P0 15 13 CPU Frequency External Clock Input Notes POH 7 5 fceu foscXF Range 1 1 Reserved Default configuration Reserved R
239. hes the content of the context pointer CP on the system stack and loads CP with the immediate value New_Bank which selects a new register bank The service routine may now use its own registers This register bank is preserved when the service routine terminates i e its contents are available on the next call Before returning RETI the previous CP is simply POPped from the system stack which returns the registers to the original bank Note The first instruction following the SCXT instruction must not use a GPR Resources that are used by the interrupting program must eventually be saved and restored e g the DPPs and the registers of the MUL DIV unit Semiconductor Group 5 15 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 5 Interrupt Response Times The interrupt response time defines the time from an interrupt request flag of an enabled interrupt source being set until the first instruction 11 being fetched from the interrupt vector location The basic interrupt response time for the C161RI is 3 instruction cycles Pipeline Stage Cycle 1 Cycle 2 Cycle 3 Cycle 4 FETCH N N 1 N 2 I DECODE N 1 N TRAP 1 TRAP 2 EXECUTE N 2 N 1 N TRAP WRITEBACK N 3 N 2 N 1 N IR Flag Interrupt Response Time Figure 5 4 Pipeline Diagram for Interrupt Response Time All instructions in the pipeline including instruction N during which the interrupt request flag is set
240. ht take to fetch the source operand from internal code memory or external memory and to write the destination operand over the external bus in an external program environment Note A bus access in this context includes all delays which can occur during an external bus cycle Semiconductor Group 5 19 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Interrupt Node Sharing Interrupt nodes may be shared between several module requests either if the requests are generated mutually exclusive or if the requests are generated at a low rate If more than one source is enabled in this case the interrupt handler will first have to determine the requesting source However this overhead is not critical for low rate requests This node sharing is controlled via the sub node interrupt control register ISNC which provides a separate request flag and enable bit for each supported request source The interrupt level used for arbitration is determined by the node control register IC ISNC F1DE EF ESFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Bit Function xxIR Interrupt Request Flag for Source xx 0 No request from source xx pending 1 Source xx has raised an interrupt request xxIE Interrupt Enable Control Bit for Source xx 0 Source xx interrupt request is disabled 1 Source xx interrupt request is enabled Sub node Control Bit Allocation Bit pos Interrupt Source Associate
241. i The functions of the A D converter are controlled by the bit addressable A D Converter Control Register ADCON Its bitfields specify the analog channel to be acted upon the conversion mode and also reflect the status of the converter ADCON FFAQ0 D0 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Bit Function ADCH ADC Analog Channel Input Selection Selects the ADC channel which is to be converted ADM ADC Mode Selection 0 Fixed Channel Single Conversion 1 Fixed Channel Continuous Conversion ADRP ADC Result Position 0 8 bit result is written to ADDAT 2 ADDAT 9 1 8 bit result is written to ADDAT O ADDAT 7 ADST ADC Start Bit 0 Stop a running conversion 1 Start conversion s ADBSY ADC Busy Flag 0 ADC is idle 1 A conversion is active ADCTC ADC Conversion Time Control Defines the ADC basic conversion clock fac 00 fac fopu 2 01 fac fopu 4 10 fac fceu 8 11 fac 7 fcpu 16 Bit field ADCH specifies the analog input channel which is to be converted Bitfield ADM selects the operating mode of the A D converter A conversion or a sequence is then started by setting bit ADST Clearing ADST stops the A D converter after a certain operation which depends on the selected operating mode The busy flag read only ADBSY is set as long as a conversion is in progress Semiconductor Group 16 3 1998 05 01 SIEMENS The Analog Digital Converter C161RI
242. iation Information about specific versions and derivatives will be made available with the devices themselves Contact your Siemens representative for up to date material Note As the architecture and the basic features i e CPU core and built in peripherals are identical for most of the currently offered versions of the C161RI the descriptions within this manual that refer to the C161RI also apply to the other variations unless otherwise noted Semiconductor Group 1 3 1998 05 01 SIEMENS Introduction C161RI 1 2 Summary of Basic Features The C161RI is an improved representative of the Siemens family of full featured 16 bit single chip CMOS microcontrollers It combines high CPU performance up to 10 million instructions per second with high peripheral functionality and means for power reduction Several key features contribute to the high performance of the C161RI the indicated timings refer to a CPU clock of 20 MHz High Performance 16 Bit CPU With Four Stage Pipeline 100 ns minimum instruction cycle time with most instructions executed in 1 cycle 500 ns multiplication 16 bit x 16 bit 1 us division 32 bit 16 bit Multiple high bandwidth internal data buses Register based design with multiple variable register banks Single cycle context switching support 16 MBytes linear address space for code and data von Neumann architecture System stack cache support with automatic stack overflow underflow de
243. ich significantly reduces the overall power consumption Flexible Peripheral Management The flexible peripheral management provides a mechanism to enable and disable each peripheral module separately In each situation e g several system operating modes standby etc only those peripherals may be kept running which are required for the respective functionality All others can be switched off It also allows the operation control of whole groups of peripherals including the power required for generating and distributing their clock input signal Other peripherals may remain active e g in order to maintain communication channels The registers of separately disabled peripherals not within a disabled group can still be accessed Periodic wakeup from Idle Mode Periodic wakeup from Idle mode combines the drastically reduced power consumption in Idle mode in conjunction with the additional power management features with a high level of system availability External signals and events can be scanned at a lower rate by periodically activating the CPU and selected peripherals which then return to powersave mode after a short time This greatly reduces the system s average power consumption Semiconductor Group 2 14 1998 05 01 SIEMENS Architectural Overview C161RI 2 5 Protected Bits The C161RI provides a special mechanism to protect bits which can be modified by the on chip hardware from being changed unintentionally by software ac
244. ide open drain outputs i e no upper transistor This ensures that the I C module does not put any load on the I C bus lines while the C161Hl is not powered The I C bus lines therefore require external pullup resistors approx 10 KQ for operation at 100 KBaud 2 KO for operation at 400 KBaud Note If the pins that are assigned to the IC channel s are to be used as general purpose IO they must be used for open drain outputs or as inputs All pins of the C161RI that are to be used for I C bus communication must be switched to output and their alternate function must be enabled by setting the respective port output latch to 1 before any communication can be established If not driven by the C module i e the corresponding enable bit in register ICCFG is 0 they then switch off their drivers i e driving 1 to an open drain output Due to the external pullup devices the respective bus levels will then be 1 which is idle The FC module features digital input filters in order to improve the rejection of noise from the external bus lines Semiconductor Group 17 5 1998 05 01 SIEMENS The I2C Bus Module C161RI 17 3 Operating the PC Bus The on chip I C bus module of the C161RI can be operated in variety of operating modes Master or Slave operation can be selected so theI C module can control the external bus master or can be controlled via the bus slave by a remote master 7 bit or 10 bit addressing can be s
245. in four different modes see table below which are selected via bits CSWENx and CSRENx in the respective BUSCONx register CSWENx CSRENx Chip Select Mode 0 Address Chip Select Default after Reset 1 Read Chip Select 0 Write Chip Select 1 Read Write Chip Select O Read or Write Chip Select signals remain active only as long as the associated control signal RD or WR is active This also includes the programmable read write delay Read chip select is only activated for read cycles write chip select is only activated for write cycles read write chip select is activated for both read and write cycles write cycles are assumed if any of the signals WRH or WRL gets active These modes save external glue logic when accessing external devices like latches or drivers that only provide a single enable input Address Chip Select signals remain active during the complete bus cycle For address chip select signals two generation modes can be selected via bit CSCFG in register SYSCON A latched address chip select signal CSCFG 0 becomes active with the falling edge of ALE and becomes inactive at the beginning of an external bus cycle that accesses a different address window No spikes will be generated on the chip select lines and no changes occur as long as locations within the same address window or within internal memory excluding X Peripherals and XRAM are accessed An early address chip sele
246. ion Code fetch from internal ROM area Boot ROM access Boot ROM access User ROM access Data fetch from internal ROM area User ROM access User ROM access User ROM access Semiconductor Group 15 4 1998 05 01 SIEMENS The Bootstrap Loader C161RI Loading the Startup Code After sending the identification byte the BSL enters a loop to receive 32 bytes via ASCO These bytes are stored sequentially into locations 00 FA40 through 00 FA5F of the internal RAM So up to 16 instructions may be placed into the RAM area To execute the loaded code the BSL then jumps to location 00 FA40 i e the first loaded instruction The bootstrap loading sequence is now terminated the C161RI remains in BSL mode however Most probably the initially loaded routine will load additional code or data as an average application is likely to require substantially more than 16 instructions This second receive loop may directly use the pre initialized interface ASCO to receive data and store it to arbitrary user defined locations This second level of loaded code may be the final application code It may also be another more sophisticated loader routine that adds a transmission protocol to enhance the integrity of the loaded code or data It may also contain a code sequence to change the system configuration and enable the bus interface to store the received data into external memory This process may go through sever
247. ion Although most of the programmable features of the C161RI are either selected during the initialization phase or repeatedly during program execution there are some features that must be selected earlier because they are used for the first access of the program execution e g internal or external start selected via EA These selections are made during reset via the pins of PORTO which are read at the end of the internal reset sequence During reset internal pullup devices are active on the PORTO lines so their input level is high if the respective pin is left open or is low if the respective pin is connected to an external pulldown device With the coding of the selections as shown below in many cases the default option i e high level can be used The value on the upper byte of PORTO POH is latched into register RPOH upon reset the value on the lower byte POL directly influences the BUSCONO register bus mode or the internal control logic of the C161RI H 7 H6 H5 H4 H3 H2 H1 H0 L7 L6 L5 L4 L3 L2 L1 L CLKCFG SALSEL CSSEL BUSTYP ave emu Doo d o ue Internal Control Logic Only on hardware reset Clock Port 4 Port 6 Generator Logic Logic SYSCON Figure 18 4 PORTO Configuration during Reset BUSCONO Semiconductor Group 18 8 1998 06 01 SIEMENS System Reset C161RI The pins that control the operation of the internal control logic and the reserved pins are evaluated only durin
248. ion is only provided by the watchdog timer Combining the READY function with predefined waitstates is advantageous in two cases Memory components with a fixed access time and peripherals operating with READY may be grouped into the same address window The external waitstate control logic in this case would activate READY either upon the memory s chip select or with the peripheral s READY output After the predefined number of waitstates the C161RI will check its READY line to determine the end of the bus cycle For a memory access it will be low already see example a in the figure above for a peripheral access it may be delayed see example b in the figure above As memories tend to be faster than peripherals there should be no impact on system performance When using the READY function with so called normally ready peripherals it may lead to erroneous bus cycles if the READY line is sampled too early These peripherals pull their READY output low while they are idle When they are accessed they deactivate READY until the bus cycle is complete then drive it low again If however the peripheral deactivates READY after the first sample point of the C161RI the controller samples an active READY and terminates the current bus cycle which of course is too early By inserting predefined waitstates the first READY sample point can be shifted to a time where the peripheral has safely controlled the READY line e g after 2 waitstate
249. ipherals these DC and AC characteristics are subject to changes due to device improvements or specific derivatives of the standard device Therefore these characteristics are not contained in this manual but rather provided in a separate Data Sheet which can be updated more frequently Please refer to the current version of the Data Sheet of the respective device for all electrical parameters Note In any case the specific characteristics of a device should be verified before a new design is started This ensures that the used information is up to date The figures below show the pin diagrams of the C161RI They shows the location of the different supply and IO pins A detailed description of all the pins is also found in the Data Sheet Note Not all alternate functions shown in the figure below are supported by all derivatives Please refer to the corresponding descriptions in the data sheets Semiconductor Group 23 1 1998 05 01 SIEMENS Device Specification C161RI ZZZzzz IRoOibns5oquq ezZwu 22 ERENT IL oud FANH YY OLL Qo SHEM MMMM TM ADWNONTIYONT SD LO LO CN ON ON OI QN QN QV QN XO CO CO XO CO OO o 005 880 0a8a0 0a8aonraaaoraaaoa 1E 1E E HE THE TE TE HE TE TE 1E HL 3E 1E HE HE TE E 1E Socornrdvoiosdow CQ Oc 00 lF XQ LO st C2 QN T7 0000000 Oo O cO CO CO OO CO CO OO CO P5 2 AN2 1 eo L NMI P5 3 AN3
250. is flag is required to alert interrupt routines which require the use of the multiply divide hardware so they can preserve register MD This register however only needs to be saved when an interrupt routine requires use of the MD register and a previous task has not saved the current result This flag is easily tested by the Jump on Bit instructions Semiconductor Group 20 1 1998 05 01 SIEMENS System Programming C161RI Multiplication or division is simply performed by specifying the correct signed or unsigned version of the multiply or divide instruction The result is then stored in register MD The overflow flag V is set if the result from a multiply or divide instruction is greater than 16 bits This flag can be used to determine whether both word halfs must be transferred from register MD The high portion of register MD MDH must be moved into the register file or memory first in order to ensure that the MDRIU flag reflects the correct state The following instruction sequence performs an unsigned 16 by 16 bit multiplication SAVE JNB MDRIU START Test if MD was in use SCXT MDC 0010H Save and clear control register leaving MDRIU set only required for interrupted multiply divide instructions BSET SAVED indicate the save operation PUSH MDH Save previous MD contents PUSH MDL PO on System stack START MULU R1 R2 Multiply 16 16 unsigned Sets MDRIU JMPR cc NV COPYL Test for only 16 bit result MO
251. ision After a multiplication this non bit addressable register represents the low order 16 bits of the 32 bit result For long divisions the MDL register must be loaded with the low order 16 bits of the 32 bit dividend before the division is started After any division register MDL represents the 16 bit quotient MDL FEOE 07 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 i 0 rw Bit Function mdl Specifies the low order 16 bits of the 32 bit multiply and divide register MD Semiconductor Group 4 27 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Whenever this register is updated via software the Multiply Divide Register In Use MDRIU flag in the Multiply Divide Control register MDC is set to 1 The MDRIU flag is cleared whenever the MDL register is read via software When a multiplication or division is interrupted before its completion and when a new multiply or divide operation is to be performed within the interrupt service routine register MDL must be saved along with registers MDH and MDC to avoid erroneous results A detailed description of how to use the MDL register for programming multiply and divide algorithms can be found in chapter System Programming The Multiply Divide Control Register MDC This bit addressable 16 bit register is implicitly used by the CPU when it performs a multiplication or a division It is used to store the required control information for
252. isregarded and the contents of T4 is reloaded Semiconductor Group 10 16 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Auxiliary Timer in Capture Mode Capture mode for the auxiliary timers T2 and T4 is selected by setting bit field TxM in the respective register TXCON to 101 In capture mode the contents of the core timer are latched into an auxiliary timer register in response to a signal transition at the respective auxiliary timer s external input pin TxIN The capture trigger signal can be a positive a negative or both a positive and a negative transition The two least significant bits of bit field Txl are used to select the active transition see table in the counter mode section while the most significant bit Txl 2 is irrelevant for capture mode It is recommended to keep this bit cleared Txl 2 0 Note When programmed for capture mode the respective auxiliary timer T2 or T4 stops independent of its run flag T2R or T4R Edge Select Capture Register Tx a Interrupt A Request Input Interrupt cox cemere m Regresi T3OUT T30TL P33 X 2 4 T30E MCS03898 Figure 10 14 GPT1 Auxiliary Timer in Capture Mode Upon a trigger selected transition at the corresponding input pin TxIN the contents of the core timer are loaded into the auxiliary timer register and the associated interrupt request flag TxIR will be set Note The direction control bits for T2IN an
253. it addresses This allows to access data pages 3 0 within segment 0 as shown in the figure below If the user does not want to use any data paging no further action is required DPPO FEOO 00 SFR Reset Value 0000 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 rw DPP1 FEO02 01 SFR Reset Value 0001 15 14 1 11 10 9 8 7 6 5 4 3 2 1 0 3 12 rw DPP2 FE04 02 SFR Reset Value 0002 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 rw DPP3 FE06 03 SFR Reset Value 0003 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 rw Bit Function DPPxPN Data Page Number of DPPx Specifies the data page selected via DPPx Only the least significant two bits of DPPx are significant when segmentation is disabled Semiconductor Group 4 20 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI Data paging is performed by concatenating the lower 14 bits of an indirect or direct long 16 bit address with the contents of the DPP register selected by the upper two bits of the 16 bit address The contents of the selected DPP register specify one of the 1024 possible data pages This data page base address together with the 14 bit page offset forms the physical 24 bit address selectable part is driven to the address pins In case of non segmented memory mode only the two least significant bits of the implicitly selected DPP register are used to generate the physical address Thus extreme care should be taken wh
254. it storage and thus they are bit addressable System Stack The system stack may be defined within the internal RAM The size of the system stack is controlled by bitfield STKSZ in register SYSCON see table below lt STKSZ gt Stack Size Words Internal RAM Addresses Words 000 256 00 FBFE 00 FA00 Default after Reset 001 128 00 FBFE 00 FBOO 010 64 00 FBFE 00 FB80 O11 32 00 FBFE 00 FBCO 100 Reserved Do not use this combination 1015 Reserved Do not use this combination 110 Reserved Do not use this combination 1115 512 00 FDFE 00 FAO0 Note No circular stack For all system stack operations the on chip RAM is accessed via the Stack Pointer SP register The stack grows downward from higher towards lower RAM address locations Only word accesses are supported to the system stack A stack overflow STKOV and a stack underflow STKUN register are provided to control the lower and upper limits of the selected stack area These two stack boundary registers can be used not only for protection against data destruction but also allow to implement a circular stack with hardware supported system stack flushing and filling except for option 111 The technique of implementing this circular stack is described in chapter System Programming Semiconductor Group 3 5 1998 05 01 Memory Organization C161RI SIEM
255. k PUSH CALL SCXT are solved internally by the CPU logic Semiconductor Group 4 6 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI e External Memory Access Sequences The effect described here will only become noticeable when watching the external memory access sequences on the external bus e g by means of a Logic Analyzer Different pipeline stages can simultaneously put a request on the External Bus Controller EBC The sequence of instructions processed by the CPU may diverge from the sequence of the corresponding external memory accesses performed by the EBC due to the predefined priority of external memory accesses ist Write Data 2nd Fetch Code 3rd Read Data e Controlling Interrupts Software modifications implicit or explicit of the PSW are done in the execute phase of the respective instructions In order to maintain fast interrupt responses however the current interrupt prioritization round does not consider these changes i e an interrupt request may be acknowledged after the instruction that disables interrupts via IEN or ILVL or after the following instructions Timecritical instruction sequences therefore should not begin directly after the instruction disabling interrupts as shown in the following example INT OFF BCLR IEN globally disable interrupts Ina hon critical instruction CRIT 1ST ly begin of uninterruptable critical sequence CRIT LAST ly end of uninterruptable critical sequ
256. l Interrupt 6 Input P2 15 EX7IN Fast External Interrupt 7 Input Alternate Function P2 15 EX7IN P2 14 EX6IN P2 13 EX5IN P2 12 EX4IN P2 11 EX3IN P2 10 EX2IN P2 9 EX1IN Port 2 P2 8 EXOIN General Purpose Fast External Input Output Interrupt Input Figure 7 8 Port 2 IO and Alternate Functions Semiconductor Group 7 13 1998 05 01 SIEMENS Parallel Ports C161RI N Write s Open Drain Latch Read ODP2 y l Write DP2 y I T n n Direction r n Read DP2 y a Alternate Function la Enable B u Write P2 y Alternate P2y Port Output Q Latch Output Buffer Read P2 y Clock i Input Latch D EXZIN 4 MCB03783 y 15 8 zzT 0 Figure 7 9 Block Diagram of a Port 2 Pin Semiconductor Group 7 14 1998 05 01 SIEMENS Parallel Ports C161RI 7 4 Port3 If this 15 bit port is used for general purpose IO the direction of each line can be configured via the corresponding direction register DP3 Most port lines can be switched into push pull or open drain mode via the open drain control register ODP3 pins P3 15 and P3 12 do not support open drain mode Due to pin limitations register bit P3 14 is not connected to an output pin P3 FFC4 E24 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw Bit Function P3 y Port data register P3 bit y N
257. l bus even for multiplexed bus cycles Not all address windows defined via registers ADDRSELx may overlap each other The operation of the EBC will be unpredictable in such a case See chapter Address Window Arbitration The address windows defined via registers ADDRSELx may overlap internal address areas Internal accesses will be executed in this case For any access to an internal address area the EBC will remain inactive see EBC Idle State Semiconductor Group 9 24 1998 06 01 The External Bus Interface C161RI SIEMENS 9 5 EBC ldle State When the external bus interface is enabled but no external access is currently executed the EBC is idle As long as only internal resources from an architecture point of view like IRAM GPRs or SFRs etc are used the external bus interface does not change see table below Accesses to on chip X Peripherals are also controlled by the EBC However even though an X Peripheral appears like an external peripheral to the controller the respective accesses do not generate valid external bus cycles Due to timing constraints address and write data of an XBUS cycle are reflected on the external bus interface see table below The address mentioned above includes PORT1 Port 4 BHE and ALE which also pulses for an XBUS cycle The external CS signals on Port 6 are driven inactive high because the EBC switches to an internal XCS signal The external control signals RD and WR or W
258. l refer to the following derivatives C161RI LM C161RI LF This manual is valid for the mentioned derivatives Of course it refers to all devices of the different available temperature ranges and packages For simplicity all these various versions are referred to by the term C161RI throughout this manual The complete pro electron conforming designations are listed in the respective data sheets Semiconductor Group 1 1 1998 05 01 SIEMENS Introduction C161RI 1 1 The Members of the 16 bit Microcontroller Family The microcontrollers of the Siemens 16 bit family have been designed to meet the high performance requirements of real time embedded control applications The architecture of this family has been optimized for high instruction throughput and minimum response time to external stimuli interrupts Intelligent peripheral subsystems have been integrated to reduce the need for CPU intervention to a minimum extent This also minimizes the need for communication via the external bus interface The high flexibility of this architecture allows to serve the diverse and varying needs of different application areas such as automotive industrial control or data communications The core of the 16 bit family has been developed with a modular family concept in mind All family members execute an efficient control optimized instruction set additional instructions for members of the second generation This allows an easy and quick impleme
259. le conversion time 7 625 us minimum auto scan modes channel injection mode 2 Multifunctional General Purpose Timer Units GPT1 three 16 bit timers counters maximum resolution fcpy 8 GPT2 two 16 bit timers counters maximum resolution fopy 4 Asynchronous Synchronous Serial Channel USART with baud rate generator parity framing and overrun error detection High Speed Synchronous Serial Channel programmable data length and shift direction FC Bus Module with 10 bit addressing and 400 Kbit sec Real Time Clock Watchdog Timer with programmable time intervals Bootstrap Loader for flexible system initialization 76 IO Lines With Individual Bit Addressability Tri stated in input mode Push pull or open drain output mode Different Temperature Ranges 0 to 70 C 40 to 85 C Siemens CMOS Process Low Power CMOS Technology including power saving Idle and Power Down modes 100 Pin Plastic Quad Flat Pack PQFP Packages P MQFP 14x20 mm body 0 65 mm 25 6 mil lead spacing surface mount technology P TQFP 14x 14 mm body 0 5 mm 19 7 mil lead spacing surface mount technology Semiconductor Group 1 5 1998 05 01 SIEMENS Introduction C161RI Complete Development Support For the development tool support of its microcontrollers Siemens follows a clear third party concept Currently around 120 tool suppliers world wide ranging from local niche manufacturers to multinational companies with broad produ
260. lf of segment 0 or the internal ROM may be disabled at all Code and data may be stored in any part of the internal memory areas except for the SFR blocks which may be used for control data but not for instructions Note Accesses to the internal ROM area on ROMIess devices will produce unpredictable results Bytes are stored at even or odd byte addresses Words are stored in ascending memory locations with the low byte at an even byte address being followed by the high byte at the next odd byte address Double words code only are stored in ascending memory locations as two subsequent words Single bits are always stored in the specified bit position at a word address Bit position O is the least significant bit of the byte at an even byte address and bit position 15 is the most significant bit of the byte at the next odd byte address Bit addressing is supported for a part of the Special Function Registers a part of the internal RAM and for the General Purpose Registers k XXXX6 H e e Big XXXX5 H Bits XXXX4 H HE A Byte XXXX3 H Byte XXXX2 H Word High Byte xx H Word Low Byte XXXX0 H XXXXF H l MCD01996 Figure 3 2 Storage of Words Byte and Bits in a Byte Organized Memory Note Byte units forming a single word or a double word must always be stored within the same physical internal external ROM RAM and organizational page segment memory area Semiconductor G
261. liary timer registers T2 or T4 based on the transition at pins T2IN or TAIN When the interrupt enable bits T2IE or T4IE are set a PEC request or an interrupt request for vector T2INT or T4INT will be generated Semiconductor Group 5 21 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Pin CAPIN differs slightly from the timer input pins as it can be used as external interrupt input pin without affecting peripheral functions When the capture mode enable bit T5SC in register T5ECON is cleared to 0 signal transitions on pin CAPIN will only set the interrupt request flag CRIR in register CRIC and the capture function of register CAPREL is not activated So register CAPREL can still be used as reload register for GPT2 timer T5 while pin CAPIN serves as external interrupt input Bit field Cl in register T5CON selects the effective transition of the external interrupt input signal When Cl is programmed to 015 a positive external transition will set the interrupt request flag Cl 10g selects a negative transition to set the interrupt request flag and with Cl 115 both a positive and a negative transition will set the request flag When the interrupt enable bit CRIE is set an interrupt request for vector CRINT or a PEC request will be generated Note The non maskable interrupt input pin NMI and the reset input RSTIN provide another possibility for the CPU to react on an external input signal NMI and RSTIN are dedicated input pins
262. load Mode Since the reload function and the capture function of register CAPREL can be enabled individually by bits T5SC and T6SR the two functions can be enabled simultaneously by setting both bits This feature can be used to generate an output frequency that is a multiple of the input frequency Up Down Input NN Interrupt Clock 9 Auxiliary Timer T5 TSIR Request c p O Select A T5CLR CAPIN P3 2 j ba a Iv T5SC car L Interrupt ji CRIR Ci Y Request CAPREL Register Iv Bre Dm T6SR Input Interrupt Clock o Core Timer T6 T6IR Request 4 Up Down MCS03900 Figure 10 21 GPT2 Register CAPREL in Capture And Reload Mode This combined mode can be used to detect consecutive external events which may occur aperiodically but where a finer resolution that means more ticks within the time between two external events is required For this purpose the time between the external events is measured using timer T5 and the CAPREL register Timer T5 runs in timer mode counting up with a frequency of e g fopy 32 The external events are applied to pin CAPIN When an external event occurs the timer T5 contents are latched into register CAPREL and timer T5 is cleared T5CLR 1 Thus register CAPREL always contains the correct time between two events measured in timer T5 increments Timer T6 which runs in timer mode counting down with a frequency of e g fopy 4 uses the value in register
263. low efficient interrupt service and also support operation via PEC transfers Note The port pins associated with the IC interfaces feature open drain drivers only as required by the FC specification Semiconductor Group 2 11 1998 05 01 SIEMENS Architectural Overview C161RI General Purpose Timer GPT Unit The GPT units represent a very flexible multifunctional timer counter structure which may be used for many different time related tasks such as event timing and counting pulse width and duty cycle measurements pulse generation or pulse multiplication Each timer may operate independently in a number of different modes or may be concatenated with another timer of the same module Each timer can be configured individually for one of four basic modes of operation which are Timer Gated Timer Counter Mode and Incremental Interface Mode GPT1 timers In Timer Mode the input clock for a timer is derived from the internal CPU clock divided by a programmable prescaler while Counter Mode allows a timer to be clocked in reference to external events via TxIN Pulse width or duty cycle measurement is supported in Gated Timer Mode where the operation of a timer is controlled by the gate level on its external input pin TxIN In Incremental Interface Mode the GPT1 timers can be directly connected to the incremental position sensor signals A and B via the respective inputs TxIN and TxEUD Direction and count signals are internally derive
264. m stack POP Saving of a word on the system stack and then updating the old word with a new value provided for register bank switching SCXT Semiconductor Group 22 2 1998 05 01 SIEMENS Instruction Set Summary C161RI Jump Instructions Conditional jumping to an either absolutely indirectly or relatively addressed target instruction within the current code segment Unconditional jumping to an absolutely addressed target instruction within any code segment Conditional jumping to a relatively addressed target instruction within the current code segment depending on the state of a selectable bit Conditional jumping to a relatively addressed target instruction within the current code segment depending on the state of a selectable bit with a post inversion of the tested bit in case of jump taken semaphore support Call Instructions Conditional calling of an either absolutely or indirectly addressed subroutine within the current code segment Unconditional calling of a relatively addressed subroutine within the current code segment Unconditional calling of an absolutely addressed subroutine within any code segment Unconditional calling of an absolutely addressed subroutine within the current code segment plus an additional pushing of a selectable register onto the system stack Unconditional branching to the interrupt or trap vector jump table in code segment 0 Return Instructions Returning from a sub
265. me Clock C161RI T14REL Interrupt Request Figure 14 2 RTC Block Diagram System Clock Operation A real time system clock can be maintained that keeps on running also during idle mode and power down mode optionally and represents the current time and date This is possible as the RTC module is not effected by a reset The maximum resolution minimum stepwidth for this clock information is determined by timer T14 s input clock The maximum usable timespan is achieved when T14REL is loaded with 0000 and so T14 divides by 216 Cyclic Interrupt Generation The RTC module can generate an interrupt request whenever timer T14 overflows and is reloaded This interrupt request may e g be used to provide a system time tick independent of the CPU frequency without loading the general purpose timers or to wake up regularly from idle mode The interrupt cycle time can be adjusted via the timer T14 reload register T14REL Please refer to RTC Interrupt Generation below for more details 48 bit Timer Operation The concatenation of the 16 bit reload timer T14 and the 32 bit RTC timer can be regarded as a 48 bit timer which is clocked with the RTC input frequency divided by the fixed prescaler The reload register T14REL should be cleared to get a 48 bit binary timer However any other reload value may be used The maximum usable timespan is 2 10 T14 input clocks which would equal more than 100 years at an o
266. mers count up Semiconductor Group 2 13 1998 05 01 SIEMENS Architectural Overview C161RI 2 4 Power Management Features The known basic power reduction modes Idle and Power Down are enhanced by a number of additional power management features see below These features can be combined to reduce the controller s power consumption to the respective application s possible minimum Flexible clock generation Flexible peripheral management peripherals can be enabled disabled separately or in groups Periodic wakeup from Idle mode via RTC timer The listed features provide effective means to realize standby conditions for the system with an optimum balance between power reduction i e standby time and peripheral operation i e system functionality Flexible Clock Generation The flexible clock generation system combines a variety of improved mechanisms partly user controllable to provide the C161RI modules with clock signals This is especially important in power sensitive modes like standby operation The power optimized oscillator generally reduces the amount of power which is consumed in order to generate the clock signal within the C161RI The clock system efficiently controls the amount of power which is consumed in order to distribute the clock signal within the C161Hl Slowdown operation is achieved by dividing the oscillator clock by a programmable factor 1 32 resulting in a low frequency device operation wh
267. miconductor Group 10 10 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT1 Auxiliary Timers T2 and TA Both auxiliary timers T2 and T4 have exactly the same functionality They can be configured for timer gated timer counter or incremental interface mode with the same options for the timer frequencies and the count signal as the core timer T3 In addition to these 4 counting modes the auxiliary timers can be concatenated with the core timer or they may be used as reload or capture registers in conjunction with the core timer The individual configuration for timers T2 and T4 is determined by their bitaddressable control registers T2CON and T4CON which are both organized identically Note that functions which are present in all 3 timers of block GPT1 are controlled in the same bit positions and in the same manner in each of the specific control registers T2CON FF40 AOp SFR Reset Value 0000 15 14 13 12 1i 10 9 8 7 6 5 4 3 2 1 0 T2 rw rw rw rw rw T4CON FF44 A2 SFR Reset Value 0000 15 14 13 12 1i 10 9 8 7 6 5 4 3 2 1 0 T4 rw rw rw rw rw Bit Function Txl Timer x Input Selection Depends on the Operating Mode see respective sections TxM Timer x Mode Control Basic Operating Mode 000 Timer Mode 001 Counter Mode 010 Gated Timer with Gate active low 011 Gated Timer with Gate active high 100 Reload Mode 101 Capture Mode 110 Incremental Interface Mode T
268. mode both the CPU and the peripherals are stopped The real time clock and its selected oscillator may optionally be kept running Power Down mode can only be terminated by a hardware reset Note All external bus actions are completed before Idle or Power Down mode is entered However Idle or Power Down mode is not entered if READY is enabled but has not been activated driven low during the last bus access In addition the power management selects the current CPU frequency and controls which peripherals are active During Slow Down operation the basic clock generation path is bypassed and the CPU clock is generated via the programmable Slow Down Divider SDD from the selected oscillator clock signal Peripheral Management disables and enables the on chip peripheral modules independently reducing the amount of clocked circuitry including the respective clock drivers 19 1 Idle Mode The power consumption of the C161RI microcontroller can be decreased by entering Idle mode In this mode all enabled peripherals including the watchdog timer continue to operate normally only the CPU operation is halted and the on chip memory modules are disabled Note Peripherals that have been disabled via software also remain disabled after entering Idle mode of course Idle mode is entered after the IDLE instruction has been executed and the instruction before the IDLE instruction has been completed To prevent unintentional entry into Idle mode th
269. mory N 00 C000 00 F000 lC 00 EDO0 X Reserved aW Ext Memory O0 E7FF a 00 8000 00 E000 Note New XBUS peripherals will be preferably placed into the shaded areas which now access external memory bus cycles executed Figure 3 3 System Memory Map Semiconductor Group 3 4 1998 05 01 SIEMENS Memory Organization C161RI Note The upper 256 bytes of SFR area ESFR area and internal RAM are bit addressable see hashed blocks in the figure above Code accesses are always made on even byte addresses The highest possible code storage location in the internal RAM is either 00 FDFE for single word instructions or 00 FDFC for double word instructions The respective location must contain a branch instruction unconditional because sequential boundary crossing from internal RAM to the SFR area is not supported and causes erroneous results Any word and byte data in the internal RAM can be accessed via indirect or long 16 bit addressing modes if the selected DPP register points to data page 3 Any word data access is made on an even byte address The highest possible word data storage location in the internal RAM is 00 FDFE For PEC data transfers the internal RAM can be accessed independent of the contents of the DPP registers via the PEC source and destination pointers The upper 256 Byte of the internal RAM 00 FDO0O through 00 FDFF and the GPRs of the current bank are provided for single b
270. ms FFFF Note The contents of SSCBR must be gt 0 Semiconductor Group 12 11 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI 12 4 Error Detection Mechanisms The SSC is able to detect four different error conditions Receive Error and Phase Error are detected in all modes while Transmit Error and Baudrate Error only apply to slave mode When an error is detected the respective error flag is set When the corresponding Error Enable Bit is set also an error interrupt request will be generated by setting SSCEIR see figure below The error interrupt handler may then check the error flags to determine the cause of the error interrupt The error flags are not reset automatically like SSCEIR but rather must be cleared by software after servicing This allows servicing of some error conditions via interrupt while the others may be polled by software Note The error interrupt handler must clear the associated enabled errorflag s to prevent repeated interrupt requests A Receive Error Master or Slave mode is detected when a new data frame is completely received but the previous data was not read out of the receive buffer register SSCRB This condition sets the error flag SSCRE and when enabled via SSCREN the error interrupt request flag SSCEIR The old data in the receive buffer SSCRB will be overwritten with the new value and is unretrievably lost A Phase Error Master or Slave mode is detec
271. multi source interrupt nodes are incorporated These nodes can be activated by several source requests e g as different kinds of errors in the serial interfaces However specific status flags which identify the type of error are implemented in the serial channels control registers Additional sharing of interrupt nodes is supported via the interrupt subnode control register ISNC see description below The C161RI provides a vectored interrupt system In this system specific vector locations in the memory space are reserved for the reset trap and interrupt service functions Whenever a request occurs the CPU branches to the location that is associated with the respective interrupt source This allows direct identification of the source that caused the request The only exceptions are the class B hardware traps which all share the same interrupt vector The status flags in the Trap Flag Register TFR can then be used to determine which exception caused the trap For the special software TRAP instruction the vector address is specified by the operand field of the instruction which is a seven bit trap number The reserved vector locations build a jump table in the low end of the C161RI s address space segment 0 The jump table is made up of the appropriate jump instructions that transfer control to the interrupt or trap service routines which may be located anywhere within the address space The entries of the jump table are located at the lo
272. multiplexed Bus Modes In the demultiplexed bus modes the 16 bit intra segment address is permanently output on PORT1 while the data uses PORTO 16 bit data or POL 8 bit data The upper address lines are permanently output on Port 4 if selected via SALSEL during reset No address latches are required The EBC initiates an external access by placing an address on the address bus After a programmable period of time the EBC activates the respective command signal RD WR WRL WRH Data is driven onto the data bus either by the EBC for write cycles or by the external memory peripheral for read cycles After a period of time which is determined by the access time of the memory peripheral data become valid Read cycles Input data is latched and the command signal is now deactivated This causes the accessed device to remove its data from the data bus which is then tri stated again Write cycles The command signal is now deactivated If a subsequent external bus cycle is required the EBC places the respective address on the address bus The data remain valid on the bus until the next external bus cycle is started E Bus Cycle e Segment P4 Adorese ALE N N BUS PO ze POUR do aans TK MCD02061 Figure 9 3 Demultiplexed Bus Cycle Semiconductor Group 9 4 1998 06 01 SIEMENS The External Bus Interface C161RI Switching between the Bus M
273. n Power Down mode while still all the other circuitry is disconnected from the clock The registers of the generic peripherals can be accessed even while the respective module is disabled as long as PCD is running the registers of peripherals which are connected to ICD can be accessed even in this case of course The registers of X peripherals cannot be accessed while the respective module is disabled by any means While a peripheral is disabled its output pins remain in the state they had at the time of disabling Semiconductor Group 19 10 1998 05 01 SIEMENS Power Management C161RI Software controls this flexible peripheral mangement via register SYSCONG where each control bit is associated with an on chip peripheral module SYSCONS F1DA EA ESFR Reset Value 0000 15 14 13 42 11 40 9 8 7 6 5 4 3 2 1 0 PCD PC GPT SSC ASCO ADC Pts mop prep rw rw rw rw rw rw Bit Function associated peripheral module ADCDIS Analog Digital Converter ASCODIS USART ASCO SSCDIS Synchronous Serial Channel SSC GPTDIS General Purpose Timer Blocks I2CDIS On chip PC Bus Module PCDDIS Peripheral Clock Driver also X Peripherals Note The allocation of peripheral disable bits within register SYSCONS is device specific and may be different in other derivatives than the C161RI SYSCONS is write protected after the execution of EINIT unless it is released via the unlock sequence When disabling t
274. n of an operand For Boolean bit operations with only one operand the C flag is always cleared For Boolean bit operations with two operands the C flag represents the logical ANDing of the two specified bits e V Flag For addition subtraction and 2 s complementation the V flag is always set to 1 if the result overflows the maximum range of signed numbers which are representable by either 16 bits for word operations 8000 to 7FFF j or by 8 bits for byte operations 80 to 7F otherwise the V flag is cleared Note that the result of an integer addition integer subtraction or 2 s complement is not valid if the V flag indicates an arithmetic overflow For multiplication and division the V flag is set to 1 if the result cannot be represented in a word data type otherwise it is cleared Note that a division by zero will always cause an overflow In contrast to the result of a division the result of a multiplication is valid regardless of whether the V flag is set to 1 or not Since logical ALU operations cannot produce an invalid result the V flag is cleared by these operations The V flag is also used as Sticky Bit for rotate right and shift right operations With only using the C flag a rounding error caused by a shift right operation can be estimated up to a quantity of one half of the LSB of the result In conjunction with the V flag the C flag allows evaluating the rounding error with a finer resolution see
275. n the condition flags the PEC response time may additionally be extended by 2 state times The worst case PEC response time during internal code memory program execution adds to 9 state times 18 TCL Any reference to external locations increases the PEC response time due to pipeline related access priorities The following conditions have to be considered Instruction fetch from an external location Operand read from an external location Result write back to an external location Depending on where the instructions source and destination operands are located there are a number of combinations Note however that only access conflicts contribute to the delay A few examples illustrate these delays The worst case interrupt response time including external accesses will occur when instructions N and N 1 are executed out of external memory instructions N 1 and N require external operand read accesses and instructions N 3 N 2 and N 1 write back external operands In this case the PEC response time is the time to perform 7 word bus accesses When instructions N and N 1 are executed out of external memory but all operands for instructions N 3 through N 1 are in internal memory then the PEC response time is the time to perform 1 word bus access plus 2 state times Once a request for PEC service has been acknowledged by the CPU the execution of the next instruction is delayed by 2 state times plus the additional time it mig
276. nal while the lower byte is selected with the AO signal So the two bytes of the memory can be enabled independent from each other or together when accessing words When writing bytes to an external 16 bit device which has a single CS input but two WR enable inputs for the two bytes the EBC can directly generate these two write control signals This saves the external combination of the WR signal with AO or BHE In this case pin WR serves as WRL write low byte and pin BHE serves as WRH write high byte Bit WRCFG in register SYSCON selects the operating mode for pins WR and BHE The respective byte will be written on both data bus halfs When reading bytes from an external 16 bit device whole words may be read and the C161RI automatically selects the byte to be input and discards the other However care must be taken when reading devices that change state when being read like FIFOs interrupt status registers etc In this case individual bytes should be selected using BHE and AO Bus Mode Transfer Rate Speed factor System Requirements Free IO Lines for byte word dword access 8 bit Multiplexed Very low 1 5 3 6 Low 8 bit latch byte bus P1H P1L 8 bit Demultipl Low 1 2 4 Very low no latch byte bus POH 16 bit Multiplexed High 1 5 1 5 3 High 16 bit latch word bus P1H PiL 16 bit Demultipl Very high 1 1 2 Low no latch word bus Note PORT gets available for general purp
277. nd where possible operands are read from or written to The fastest processing mode of the C161RI is to execute a program fetched from the internal code memory In that case most of the instructions can be processed within just one machine cycle which is also the general minimum execution time All external memory accesses are performed by the C161RI s on chip External Bus Controller EBC which works in parallel with the CPU This section summarizes the execution times in a very condensed way A detailed description of the execution times for the various instructions and the specific exceptions can be found in the C16x Family Instruction Set Manual The table below shows the minimum execution times required to process a C161RI instruction fetched from the internal code memory the internal RAM or from external memory These execution times apply to most of the C161RI instructions except some of the branches the multiplication the division and a special move instruction In case of internal ROM program execution there is no execution time dependency on the instruction length except for some special branch situations The numbers in the table are in units of CPU clock cycles and assume no waitstates Minimum Execution Times Instruction Fetch Word Operand Access Memory Area Word Doubleword Read from Write to Instruction Instruction Internal code memory 2 2 2 Internal RAM 6 8 0 1 0 16 bit Demux Bus 2 4 2 2
278. nerally enabled No External bus No External bus external bus enabled external bus enabled ALE Low Low Low Low RD WR High High High High CLKOUT Active Active High High RSTOUT 1 1 1 1 POL Port Latch Data Floating Port Latch Data Floating POH Port Latch Data A15 A8 Float Port Latch Data A15 A8 Float PORT1 Port Latch Data Last Address Port Latch Data Last Address Port Latch Data Port Latch Data Port 4 Port Latch Data Port Latch Data Port Latch Data Port Latch Data Last segment Last segment BHE Port Latch Data Last value Port Latch Data Last value CSx Port Latch Data Last value Port Latch Data Last value Other Port Port Latch Data Port Latch Data Port Latch Data Port Latch Data Output Pins Alternate Function Alternate Function Alternate Function Alternate Function Note 1 High if EINIT was executed before entering Idle or Power Down mode Low otherwise N 4 For demultiplexed buses For multiplexed buses with 8 bit data bus The CS signal that corresponds to the last address remains active low all other enabled CS signals remain inactive high By accessing an on chip X Periperal prior to entering a power save mode all external CS signals can be deactivated Semiconductor Group 19 6 1998 05 01 SIEMENS Power Management C161RI 19 3 Slow Down Operation A separate clock path can be selecte
279. nfiguration for an address area that currently supplies the instruction stream Due to the internal pipelining it is very difficult to determine the first instruction fetch that will use the new configuration Only change the configuration for address areas that are not currently accessed This applies to BUSCON registers as well as to ADDRSEL registers The usage of the BUSCON ADDRSEL registers is controlled via the issued addresses When an access code fetch or data is initiated the respective generated physical address defines if the access is made internally uses one of the address windows defined by ADDRSEL4 1 or uses the default configuration in BUSCONO After initializing the active registers they are selected and evaluated automatically by interpreting the physical address No additional switching or selecting is necessary during run time except when more than the four address windows plus the default is to be used Switching from demultiplexed to multiplexed bus mode represents a special case The bus cycle is started by activating ALE and driving the address to Port 4 and PORT1 as usual if another BUSCON register selects a demultiplexed bus However in the multiplexed bus modes the address is also required on PORTO In this special case the address on PORTO is delayed by one CPU clock cycle which delays the complete multiplexed bus cycle and extends the corresponding ALE signal see figure below This extra time is required t
280. nfiguration has been specified the ILLBUS flag in register TFR is set and the CPU enters the illegal bus access trap routine The IP value pushed onto the system stack is the address of the instruction following the one which caused the trap Semiconductor Group 5 27 1998 05 01 SIEMENS Clock Generation C161RI 6 Clock Generation All activities of the C161RI s controller hardware and its on chip peripherals are controlled via the system clock signal fopu This reference clock is generated in three stages see also figure below Oscillator The on chip Pierce oscillator can either run with an external crystal and appropriate oscillator circuitry or it can be driven by an external oscillator Frequency Control The input clock signal feeds the controller hardware directly providing phase coupled operation on not too high input frequency divided by 2 in order to get 50 duty cycle clock signal Via the Slow Down Divider SDD in order to reduce the power consumption The resulting internal clock signal is referred to as CPU clock fep Clock Drivers The CPU clock is distributed via separate clock drivers which feed the CPU itself and two groups of peripheral modules The RTC is fed with the prescaled oscillator clock fRtc via a separate clock driver so it is not affected by the clock control functions Idle mode CPU Prescaler PCDDIS Peripherals Ports Intr Ctrl SDD Interfaces
281. nfiguration is automatically set values that deviate from the normal reset values are marked Watchdog Timer Disabled Register STKUN FA40 Context Pointer CP FAO00 Register STKOV FAOC 0 lt gt C Stack Pointer SP FA40 Register BUSCONO acc to startup config Register SOCON 80114 P3 10 TXDO T Register SOBG acc to 00 byte DP3 10 T Other than after a normal reset the watchdog timer is disabled so the bootstrap loading sequence is not time limited Pin TXDO is configured as output so the C161RI can return the identification byte Note Even if the internal ROM OTP Flash is enabled no code can be executed out of it The hardware that activates the BSL during reset may be a simple pull down resistor on POL 4 for systems that use this feature upon every hardware reset You may wantto use a switchable solution via jumper or an external signal for systems that only temporarily use the bootstrap loader Semiconductor Group 15 2 1998 05 01 SIEMENS The Bootstrap Loader C161RI I External Signal 2 7s D Circuit 2 POL 4 POL 4 MCA0226 Figure 15 2 Hardware Provisions to Activate the BSL After sending the identification byte the ASCO receiver is enabled and is ready to receive the initial 32 bytes from the host A half duplex connection is therefore sufficient to feed the BSL Note In order to properly enter BSL mode it is not only re
282. ngine of the C161RI controller it is also affected by certain actions of the peripheral subsystem Since a four stage pipeline is implemented in the C161RI up to four instructions can be processed in parallel Most instructions of the C161RI are executed in one machine cycle 2 CPU clock periods due to this parallelism This chapter describes how the pipeline works for sequential and branch instructions in general and which hardware provisions have been made to speed the execution of jump instructions in particular The general instruction timing is described including standard and exceptional timing While internal memory accesses are normally performed by the CPU itself external peripheral or memory accesses are performed by a particular on chip External Bus Controller EBC which is automatically invoked by the CPU whenever a code or data address refers to the external address space If possible the CPU continues operating while an external memory access is in progress If external data are required but are not yet available or if a new external memory access is requested by the CPU before a previous access has been completed the CPU will be held by the EBC until the request can be satisfied The EBC is described in a dedicated chapter Internal SP STKOV TRIN Exec Unit Mul Div HW Instr Ptr Bit Mask Gen General Instr Reg 32 Purpose ROM 4 Slage 16 bit Pipeline Registers j Barrel Shifter 9 PSW SYSCON Dat
283. nies Bawa ead RF ARE DEI P 1 4 1 3 Abbrevialtlorns xc oer ewe r Ee CHEER Res Soe e hee Sue ed dey a 1 7 2 Architectural Overview 0 00 c eet nee 2 1 2 1 Basic CPU Concepts and Optimizations 00000 ee ee 2 2 2 2 High Instruction Bandwidth Fast Execution 00 00 eee 2 3 2 3 Programmable Multiple Priority Interrupt System 20 0000 e eee 2 6 2 4 The On chip System Resources 00 00 eee eee 2 7 2 5 The On chip Peripheral Blocks 2 4 2 408 out ee aere ERE Dea sus 2 9 2 6 Power Management Features 2 000 e cece ete ees 2 14 2 7 Protected BIIS o tee RE D eel eet eke Seow a DE ERI EEEETES 2 15 3 Memory Organization cep tae RYE Qe erre RR ana 3 1 3 1 internal ROM sce aoe d drenar eene Sees PL ee bere vie iuu tis 3 3 3 2 Internal RAM and SFR Area iosses iip REOR RRESESENIG NOE Re A EE 3 4 3 3 The OfsChip XBAM c eue eer exo ex qose th eee e Ft one SOS de eae 3 9 3 4 External Memory Space ooxxwbepRRRTEGARSIRERGa RUE HAE ume MES 3 10 3 5 Crossing Memory Boundaries 2 cc eee eee tees 3 11 4 The Central Processing Unit CPU ccc eee es 4 1 4 1 Instruction Pipelining ss Sis io es Lace Ea e hr Ces ut d Fiet e a eee afe tate ae 4 3 4 2 Particular Pipeline Effects 23e eve ERR e ee De eqs 4 6 4 3 Bit Handling and Bit Protection 24s ete duce RE eG wha werd eee oe slew nea 4 9 4 4 Instruction State TIMES i443 4 nena cia totp sapeu eee kee AEE BERE hee 4
284. nments for today s microcontrollers Complex control algorithms have to be processed based on a large number of digital as well as analog input signals and the appropriate output signals must be generated within a defined maximum response time Embedded control applications also are often sensitive to board space power consumption and overall system cost Embedded control applications therefore require microcontrollers which e offer a high level of system integration eliminate the need for additional peripheral devices and the associated software overhead provide system security and fail safe mechanisms provide effective means to control and reduce the device s power consumption With the increasing complexity of embedded control applications a significant increase in CPU performance and peripheral functionality over conventional 8 bit controllers is required from microcontrollers for high end embedded control systems In order to achieve this high performance goal Siemens has decided to develop its family of 16 bit CMOS microcontrollers without the constraints of backward compatibility Of course the architecture of the 16 bit microcontroller family pursues successful hardware and software concepts which have been established in Siemens popular 8 bit controller families About this Manual This manual describes the functionality of the 16 bit microcontroller C161RI of the Siemens C166 family The descriptions in this manua
285. nstruction which is capable of addressing the SFR memory space a lot of flexibility has been gained without the need to create a set of system specific instructions Note however that there are user access restrictions for some of the CPU core SFRs to ensure proper processor operations The instruction pointer IP and code segment pointer CSP cannot be accessed directly at all They can only be changed indirectly via branch instructions The PSW SP and MDC registers can be modified not only explicitly by the programmer but also implicitly by the CPU during normal instruction processing Note that any explicit write request via software to an SFR supersedes a simultaneous modification by hardware of the same register Note Any write operation to a single byte of an SFR clears the non addressed complementary byte within the specified SFR Non implemented reserved SFR bits cannot be modified and will always supply a read value of 0 The System Configuration Register SYSCON This bit addressable register provides general system configuration and control functions The reset value for register SYSCON depends on the state of the PORTO pins during reset see hardware effectable bits SYSCON FF12 89 SFR Reset Value 0XX0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SGT BYT CLK WR CS BDRS VISI XPER rw w w WwW w w w ew w w w mw rm XPER SHARE XBUS Peripheral Share Mode Control Bit Function 0 External accesses to X
286. nstructions have been optimized to require one extra machine cycle only when a branch is taken This is implemented by precalculating the target address while decoding the instruction To decrease loop execution overhead three enhancements have been provided The first solution provides single cycle branch execution after the first iteration of a loop Thus only one machine cycle is lost during the execution of the entire loop In loops which fall through upon completion no machine cycles are lost when exiting the loop No special instructions are required to perform loops and loops are automatically detected during execution of branch instructions The second loop enhancement allows the detection of the end of a table and avoids the use of two compare instructions embedded in loops One simply places the lowest negative number at the end of the specific table and specifies branching if neither this value nor the compared value have been found Otherwise the loop is terminated if either condition has been met The terminating condition can then be tested The third loop enhancement provides a more flexible solution than the Decrement and Skip on Zero instruction which is found in other microcontrollers Through the use of Compare and Increment or Decrement instructions the user can make comparisons to any value This allows loop counters to cover any range This is particularly advantageous in table searching Semiconductor Group 2 4 1998 0
287. ntation of new family members with different internal memory sizes and technologies different sets of on chip peripherals and or different numbers of IO pins The XBUS concept opens a straight forward path for the integration of application specific peripheral modules in addition to the standard on chip peripherals in order to build application specific derivatives As programs for embedded control applications become larger high level languages are favoured by programmers because high level language programs are easier to write to debug and to maintain The 80C166 type microcontrollers were the first generation of the 16 bit controller family These devices have established the C166 architecture The C165 type and C167 type devices are members of the second generation of this family This second generation is even more powerful due to additional instructions for HLL support an increased address space increased internal RAM and highly efficient management of various resources on the external bus Enhanced derivatives of this second generation provide additional features like additional internal high speed RAM an integrated CAN Module an on chip PLL etc Utilizing integration to design efficient systems may require the integration of application specific peripherals to boost system performance while minimizing the part count These efforts are supported by the so called XBUS defined for the Siemens 16 bit microcontrollers second gene
288. nterrupt and Trap Functions C161RI When internal hold conditions between instruction pairs N 2 N 1 or N 1 N occur or instruction N explicitly writes to the PSW or the SP the minimum interrupt response time may be extended by 1 state time for each of these conditions When instruction N reads an operand from the internal code memory or when N is a call return trap or MOV Rn Rm data16 instruction the minimum interrupt response time may additionally be extended by 2 state times during internal code memory program execution In case instruction N reads the PSW and instruction N 1 has an effect on the condition flags the interrupt response time may additionally be extended by 2 state times The worst case interrupt response time during internal code memory program execution adds to 12 state times 24 TCL Any reference to external locations increases the interrupt response time due to pipeline related access priorities The following conditions have to be considered Instruction fetch from an external location Operand read from an external location Result write back to an external location Depending on where the instructions source and destination operands are located there are a number of combinations Note however that only access conflicts contribute to the delay A few examples illustrate these delays The worst case interrupt response time including external accesses will occur when instructions N N
289. o 5i 9 toic pioici e nw GO SS SOS 9 9 2 Oaqoaar gt r gt oannoananaananananananananaaezere eee d aa ES IE P s HE E eae e rs qp s Sonon oNN A Q Q9 o rr Q0 x00 ooo Qo 60000000 DOO ONN N P5 14 T4EUD 75 M Voo P5 15 T2EUD 74 Vss Msg 73 1 P1H 7 A15 XTAL1 72 P1H 6 A14 71 P1H 5 A13 70 P1H 4 A12 69 P1H 3 A11 68 P1H 2 A10 67 P1H 1 A9 P3 0 SCLO P3 1 SDAO P3 2 CAPIN P3 3 T3OUT 66 M P1H 0 A8 P3 4 T3EUD 65 A Voo P3 5 T4IN 64 Vss P3 6 T3IN C161RI 63 P1L 7 A7 P3 7 T2IN P3 8 MRST P3 9 MTSR P3 10 TxDO P3 11 RxDO P3 12 BHE WRH P3 13 SCLK P3 15 CLKOUT Vss Vop P4 0 A16 P4 1 A17 62 E P1L 6 A6 61 F P1L 5 A5 60 7 P1L 4 A4 59 P1L 3 A3 58 P1L 2 42 57 A P1L 1 A1 56 P1L 0 A0 55 POH 7 AD15 54 F POH 6 AD14 53 7 POH 5 AD13 52 P0H 4 AD12 51 F POH 3 AD1 1 OANOOaAKRWNDY O NNNNNNHHHBFHeHerFrH Het OONnNnoahWDND RoONM o oa oR O00 OQ A CO TO QO F O00 CO QN COO SF OON OD OO CI CN QU QUI CO CO CO C20 C0 C20 CO CO CO CO TAT SF s s tto EIL AE UJEILETETETETETETETETETETE TE TE TE TE TE IE E TETETLE AMDOrADMDHYPUE AOKAMYTNOR HADHO To OON QN Ic 1 5 Oonynoaadaaodaadaonolnouo 2 2n0207 z 02000ED2h 4752502559 Seas RA E m Ld S CWOSIODOIKRM ons Pease e E dddddddd FES agdadcadad cas Figure 23 2 Pin Description for C161RI P TQFP 100 Package Semiconductor Group 23 3 1998 05 01 SIEMENS Keyword In
290. o allow the previously selected device via demultiplexed bus to release the data bus which would be available in a demultiplexed bus cycle Semiconductor Group 9 5 1998 06 01 SIEMENS The External Bus Interface C161RI Demultiplexed Multiplexed Bus Cycle ideo Bus Cycle rores P N Aes Segment P4 Address Address ALE N Buso DL XC puer wer 0X MCD02234 Figure 9 4 Switching from Demultiplexed to Multiplexed Bus Mode Semiconductor Group 9 6 1998 06 01 SIEMENS The External Bus Interface C161RI External Data Bus Width The EBC can operate on 8 bit or 16 bit wide external memory peripherals A 16 bit data bus uses PORTO while an 8 bit data bus only uses POL the lower byte of PORTO This saves on address latches bus transceivers bus routing and memory cost on the expense of transfer time The EBC can control word accesses on an 8 bit data bus as well as byte accesses on a 16 bit data bus Word accesses on an 8 bit data bus are automatically split into two subsequent byte accesses where the low byte is accessed first then the high byte The assembly of bytes to words and the disassembly of words into bytes is handled by the EBC and is transparent to the CPU and the programmer Byte accesses on a 16 bit data bus require that the upper and lower half of the memory can be accessed individually In this case the upper byte is selected with the BHE sig
291. o avoid complex addressing modes which are not frequently used This decreases the instruction decode time while also simplifying the development of compilers and assem blers 3 Provide most frequently used instructions with one word instruction formats All other instruc tions are placed into two word formats This allows all instructions to be placed on word boundaries which alleviates the need for complex alignment hardware It also has the bene fit of increasing the range for relative branching instructions The high performance offered by the hardware implementation of the CPU can efficiently be utilized by a programmer via the highly functional C161RI instruction set which includes the following instruction classes Arithmetic Instructions Logical Instructions Boolean Bit Manipulation Instructions Compare and Loop Control Instructions Shift and Rotate Instructions Prioritize Instruction Data Movement Instructions System Stack Instructions Jump and Call Instructions Return Instructions System Control Instructions Miscellaneous Instructions Possible operand types are bits bytes and words Specific instruction support the conversion extension of bytes to words A variety of direct indirect or immediate addressing modes are provided to specify the required operands Semiconductor Group 2 5 1998 05 01 SIEMENS Architectural Overview C161RI Programmable Multiple Priority Interrupt System T
292. o provide access to library routines tables etc If the internal code memory only contains the startup code and or test software the system may be booted from internal memory which may then be disabled after the software has switched to executing from e g external memory in order to free the address space occupied by the internal code memory which is now unnecessary Semiconductor Group 20 14 1998 05 01 SIEMENS System Programming C161RI 20 11 Pits Traps and Mines Although handling the internal code memory provides powerful means to enhance the overall performance and flexibility of a system extreme care must be taken in order to avoid a system crash Instruction memory is the most crucial resource for the C161RI and it must be made sure that it never runs out of it The following precautions help to take advantage of the methods mentioned above without jeopardizing system security Internal code memory access after reset When the first instructions are to be fetched from internal memory EA 1 the device must contain code memory and this must contain a valid reset vector and valid code at its destination Mapping the internal ROM area to segment 1 Due to instruction pipelining any new ROM mapping will at the earliest become valid for the second instruction after the instruction which has changed the ROM mapping To enable accesses to the ROM area after mapping a branch to the newly selected ROM area JMPS and reloa
293. occurs when bit SLA is set i e a slave address is received or when bit AL is set i e the bus arbitration has been lost As long as either interrupt request flag IRQD or IRQP of the I C bus module is set the selected clock line s SCLx is are held low This disables any further transfer on the C bus and enables the driver software to react on the recent event When both request bits are cleared the clock line s is are released again and subsequent bus transfers can take place Note The interrupt node request bits XPOIR and XP1IR are cleared automatically when the CPU services the respective interrupt not in case of polling The I C bus module interrupt request bit IRQP must be cleared via the driver software The I C bus module interrupt request bit IRQD is cleared automatically upon a read write access to buffer ICRTB if bit AIRDIS 0 otherwise it must be cleared via the driver software XPOIC F186 C3 ESFR Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 XP1IC F18E C7 ESFR Reset Value 00 ee ae re eae ee ae e e M XP1IR XP1IE ILVL GLVL rw rw rw rw Note Please refer to the general Interrupt Control Register description for an explanation of the control fields Semiconductor Group 17 12 1998 05 01 SIEMENS The I2C Bus Module C161RI 17 5 Programming Example The sample program below illustrates an FC communication between the C161RI and an NVRAM such as SDA2526 or SLA24
294. odes The EBC allows to switch between different bus modes dynamically i e subsequent external bus cycles may be executed in different ways Certain address areas may use multiplexed or demultiplexed buses or use READY control or predefined waitstates A change of the external bus characteristics can be initiated in two different ways Reprogramming the BUSCON and or ADDRSEL registers allows to either change the bus mode for a given address window or change the size of an address window that uses a certain bus mode Reprogramming allows to use a great number of different address windows more than BUSCONs are available on the expense of the overhead for changing the registers and keeping appropriate tables Switching between predefined address windows automatically selects the bus mode that is associated with the respective window Predefined address windows allow to use different bus modes without any overhead but restrict their number to the number of BUSCONs However as BUSCONO controls all address areas which are not covered by the other BUSCONS this allows to have gaps between these windows which use the bus mode of BUSCONO PORT will output the intra segment address when any of the BUSCON registers selects a demultiplexed bus mode even if the current bus cycle uses a multiplexed bus mode This allows to have an external address decoder connected to PORT1 only while using it for all kinds of bus cycles Note Never change the co
295. of the pin must be programmed for input DPx y 0 if an external device is driving the pin The input direction is the default after reset If no external device is connected to the pin however one can also set the direction for this pin to output In this case the pin reflects the state of the port output latch Thus the alternate input function reads the value stored in the port output latch This can be used for testing purposes to allow a software trigger of an alternate input function by writing to the port output latch On most of the port lines the user software is responsible for setting the proper direction when using an alternate input or output function of a pin This is done by setting or clearing the direction control bit DPx y of the pin before enabling the alternate function There are port lines however where the direction of the port line is switched automatically For instance in the multiplexed external bus modes of PORTO the direction must be switched several times for an instruction fetch in order to output the addresses and to input the data Obviously this cannot be done through instructions In these cases the direction of the port line is switched automatically by hardware if the alternate function of such a pin is enabled To determine the appropriate level of the port output latches check how the alternate data output is combined with the respective port latch output Semiconductor Group 7 4 1998 05 01 SIEM
296. ol Port 5 pins may be used for both digital an analog input By setting the respective bit in register P5DIDIS the digital input stage of the respective port 5 pin can be disconnected from the pin This is recommended when the pin is to be used as analog input as it reduces the current through the digital input stage and prevents it from toggling while the analog input level is between the digital low and high thresholds So the consumed power and the generated noise can be reduced After reset all digital inputs are enabled P5DIDIS FFA4 D2 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Bit Function P5D y Port P5 Bit y Digital Input Control P5D y 0 Digital input stage connected to port line P5 y P5D y 1 Digital input stage disconnected from port line P5 y Semiconductor Group 7 24 1998 05 01 SIEMENS Parallel Ports C161RI Port 5 pins have a special port structure see figure below first because it is an input only port and second because the analog input channels are directly connected to the pins rather than to the input latches ZN I Channel n Select Analog t to Switch e Sample Hold 4 gt P5 y ANy 4 Circuit g Read Port P5 y Clock B m Input u Read Latch S Buffer A ie Ce Enable ata P5DIDIS y 7 0 Input MCB02076 Figure 7 16 Block Diagram of a Port 5 Pin Semiconductor Group 7 25 1998 05 01 SIEMENS Parallel Ports C161RI 7
297. ol the low byte of an external 16 bit device WRL together with the signal WRH alternate function of P3 12 BHE During accesses to on chip X Peripherals WR WRL remains inactive high During reset an internal pullup ensures an inactive high level on the R WRL output Semiconductor Group 8 1 1998 05 01 SIEMENS Dedicated Pins C161RI The Ready Input READY receives a control signal from an external memory or peripheral device that is used to terminate an external bus cycle provided that this function is enabled for the current bus cycle READY may be used as synchronous READY or may be evaluated asynchronously When waitstates are defined for a READY controlled address window the READY input is not evaluated during these waitstates An internal pullup ensures an inactive high level on the READY input The External Access Enable Pin EA determines if the C161RI after reset starts fetching code from the internal ROM area EA 1 or via the external bus interface EA 0 Be sure to hold this input low for ROMless devices At the end of the internal reset sequence the EA signal is latched together with the PORTO configuration The Non Maskable Interrupt Input NMI allows to trigger a high priority trap via an external signal e g a power fail signal It also serves to validate the PWRDN instruction that switches the C161RI into Power Down mode The NMI pin is sampled with every CPU clock cycle to detect transitions The
298. om of the stack may have been overwritten by the status information stacked upon servicing the stack overflow trap Automatic system stack flushing allows to use the system stack as a Stack Cache for a bigger external user stack In this case register STKOV should be initialized to a value which represents the desired lowest Top of Stack address plus 12 according to the selected maximum stack size This considers the worst case that will occur when a stack overflow condition is detected just during entry into an interrupt service routine Then six additional stack word locations are required to push IP PSW and CSP for both the interrupt service routine and the hardware trap service routine More details about the stack overflow trap service routine and virtual stack management are given in chapter System Programming Semiconductor Group 4 25 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Stack Underflow Pointer STKUN This non bit addressable register is compared against the SP register after each operation which pops data from the system stack e g POP and RET instructions and after each addition to the SP register If the content of the SP register is greater than the content of the STKUN register a stack underflow hardware trap will occur Since the least significant bit of register STKUN is tied to 0 and bits 15 through 12 are tied to 1 by hardware the STKUN register can only contain values from F
299. on The Central Processing Unit MULIP USRO Define the current status of the CPU ALU multiplication unit HLDEN HOLD Enable Enables External Bus Arbitration 0 Bus arbitration disabled P6 7 P6 5 may be used for general purpose IO 1 Bus arbitration enabled P6 7 P6 5 serve as BREQ HLDA HOLD resp ILVL CPU Priority Level Defines the current priority level for the CPU F4 Highest priority level 04 Lowest priority level IEN Interrupt Enable Control Bit globally enables disables interrupt requests 0 Interrupt requests are disabled 1 Interrupt requests are enabled CPU Priority ILVL defines the current level for the operation of the CPU This bit field reflects the priority level of the routine that is currently executed Upon the entry into an interrupt service routine this bit field is updated with the priority level of the request that is being serviced The PSW is saved on the system stack before The CPU level determines the minimum interrupt priority level that will be serviced Any request on the same or a lower level will not be acknowledged The current CPU priority level may be adjusted via software to control which interrupt request sources will be acknowledged PEC transfers do not really interrupt the CPU but rather steal a single cycle so PEC services do not influence the ILVL field in the PSW Hardware traps switch the CPU level to maximum priority i e 15 so no interru
300. on The oscillator frequency in such a case should be chosen to accommodate the required resolutions and or baudrates Semiconductor Group 19 7 1998 05 01 SIEMENS Power Management C161RI SYSCON F1D0 n ESFR Reset Value 00X0 15 14 13 12 1 0 CLK r Bit Function SYSRLS SYSCON Release Function Unlock field Must be written in a defined way in order to execute the unlock sequence See separate description PDCON Power Down Control during power down mode 00 RTC 2 On Ports On default after reset 01 RTC 2 On Ports Off 10 RTC Off Ports On 11 RTC Off Ports Off RCS RTC Clock Source not affected by a reset 0 Main oscillator 1 Reserved SCS SDD Clock Source not affected by a reset 0 Main oscillator 1 Reserved CLKCON Clock State Control 00 Running on configured basic frequency 01 Running on slow down frequency 10 Reserved Do not use this combination 11 Reserved Do not use this combination CLKREL Reload Counter Value for Slowdown Divider SDD factor CLKREL 1 CLKLOCK Clock Signal Status Bit 0 Main oscillator is unstable 1 Main oscillator is stable Any running software requires an active clock signal and so never will see CLKLOCK 0 Note SYSCON2 except for bitfield SYSRLS of course is write protected after the execution of EINIT unless it is released via the unlock sequence Semiconductor Group 19 8 1998 05 01 SIEM
301. ong Hardware Reset X X X Short Hardware Reset X X Software Reset m X Watchdog Timer Reset 7 X X When the bidirectional reset mode is enabled the indicated flags are also set in the respective reset case The WDTCON reset value will then be different from the table value Note The listed reset values for WDTCON assume the reserved bits as 0 Long Hardware Reset is indicated when the RSTIN input is still sampled low active at the end of a hardware triggered internal reset sequence Short Hardware Reset is indicated when the RSTIN input is sampled high inactive at the end of a hardware triggered internal reset sequence Software Reset is indicated after a reset triggered by the execution of instruction SRST Watchdog Timer Reset is indicated after a reset triggered by an overflow of the watchdog timer Note When bidirectional reset is enabled the RSTIN pin is pulled low for the duration of the internal reset sequence upon any sort of reset Therefore a long hardware reset LHWR will be recognized in any case Semiconductor Group 13 4 1998 05 01 SIEMENS The Real Time Clock C161RI 14 The Real Time Clock The Real Time Clock RTC module of the C161RI basically is an independent timer chain which is clocked directly with the oscillator clock and serves for different purposes System clock to determine the current time and date Cyclic time based interrupt 48 bit timer for long term measurem
302. onous mode this leaves just one bit time for the handler to respond to the transmitter interrupt request in synchronous mode itis impossible at all Using the transmit buffer interrupt SOTBIR to reload transmit data gives the time to transmit a complete frame for the service routine as SOTBUF may be reloaded while the previous data is still being transmitted ss SOTIR SOTIR Idle Synchronous Mode SORIR SORIR SORIR Figure 11 6 ASCO Interrupt Generation As shown in the figure above SOTBIR is an early trigger for the reload routine while SOTIR indicates the completed transmission Software using handshake therefore should rely on SOTIR at the end of a data block to make sure that all data has really been transmitted Semiconductor Group 11 13 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI 12 The High Speed Synchronous Serial Interface The High Speed Synchronous Serial Interface SSC provides flexible high speed serial communication between the C161RI and other microcontrollers microprocessors or external peripherals The SSC supports full duplex and half duplex synchronous communication up to 4 MBaud 16 MHz CPU clock The serial clock signal can be generated by the SSC itself master mode or be received from an external master slave mode Data width shift direction clock polarity and phase are programmable This allows communication with SPl compatible devices Transmission and
303. ons and exceptions that arise during the execution of an instruction Hardware traps always have highest priority and cause immediate system reaction The software trap function is invoked by the TRAP instruction which generates a software interrupt for a specified interrupt vector For all types of traps the current program status is saved on the system stack External Interrupt Processing Although the C161RI does not provide dedicated interrupt pins it allows to connect external interrupt sources and provides several mechanisms to react on external events including standard inputs non maskable interrupts and fast external interrupts These interrupt functions are alternate port functions except for the non maskable interrupt and the reset input Semiconductor Group 5 1 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 1 Interrupt System Structure The C161RI provides 27 separate interrupt nodes that may be assigned to 16 priority levels In order to support modular and consistent software design techniques most sources of an interrupt or PEC request are supplied with a separate interrupt control register and interrupt vector The control register contains the interrupt request flag the interrupt enable bit and the interrupt priority of the associated source Each source request is then activated by one specific event depending on the selected operating mode of the respective device For efficient usage of the resources also
304. ontrol tes cepta eet e e re pede baee 16 5 16 3 A D Converter Interrupt Control 0 0 2 ees 16 6 17 The PC Bus Module 0 02 000 c cee 17 1 17 1 PS BUS CONGHIOMSs ai ie e cL uu DELE 17 2 17 2 The Physical FC Bus Interface 21a cem RR CRT ote I SOS d 17 4 17 3 Operating the TG BUS cci xk FREE EY Re Re IRR exer SE RECER a 17 6 17 4 Operation in Master Mode a5 scs epe xe nem xk eae nada es 17 6 17 5 Operation in Multimaster Mode cee ee 17 6 17 6 Operation in Slave Mode so socie Grete a ae cr t trt ctt Ee e eh oS a 17 7 17 7 IC Interrupt COHITOI c occ eet ERE ERR See Ras ain EMT NS 17 12 17 8 Programming Example 54 2 DR ELSE UE NE ANDERE ERER 17 13 18 System HeS6t negearre nane eh t Saber Aa Et HA Up e ri ed eos 18 1 18 1 System Startup Configuration scams e epe ex E RERECREPRMR E uU RR 18 8 19 Power Management 000 c cece nh 19 1 19 1 lde Mde i m 19 2 19 2 Power Down Mode 3 vous eines nenni fe do dre PR P ee PER TE 19 4 19 3 Status of Output Pins during Power Reduction Modes 19 5 19 4 Slow DOWN Operation ceu prx EO UE dee aman uera d s 19 7 19 5 Flexible Peripheral Management 0022 c eee eee eee 19 10 20 System Programming iuuesseee e R9 9E 20 1 20 1 Stack Slot DL m 20 4 20 2 Register Banking us aus ine ati alee rbd e o M DE o da e 20 8 20 3 Procedure Call Entry and Exit edes eee y ert e a bo eset 20 8 20 4 Table Searching
305. operation SOSTP Number of Stop Bits Selection async operation 0 One stop bit T Two stop bits SOREN Receiver Enable Bit 0 Receiver disabled T Receiver enabled Reset by hardware after reception of byte in synchronous mode SOPEN Parity Check Enable Bit async operation 0 Ignore parity 1 Check parity SOFEN Framing Check Enable Bit async operation 0 Ignore framing errors 1 Check framing errors SOOEN Overrun Check Enable Bit 0 Ignore overrun errors 1 Check overrun errors SOPE Parity Error Flag Set by hardware on a parity error SOPEN 1 Must be reset by software SOFE Framing Error Flag Set by hardware on a framing error SOFEN 1 Must be reset by software SOOE Overrun Error Flag Set by hardware on an overrun error SOOEN 1 Must be reset by software SOODD Parity Selection Bit 0 Even parity parity bit set on odd number of 1 s in data qu Odd parity parity bit set on even number of 1 s in data Semiconductor Group 11 2 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI Bit Function SOBRS Baudrate Selection Bit 0 Divide clock by reload value constant depending on mode 1 Additionally reduce serial clock to 2 3rd SOLB LoopBack Mode Enable Bit 0 Standard transmit receive mode 1 Loopback mode enabled SOR Baudrate Generator Run Bit 0 Baudrate generator disabled ASCO inactive 1 Baudrate generator enabled A transmission is started
306. or the asynchronous modes when using a CPU clock of 16 MHz is 500 KBaud The table below lists various commonly used baud rates together with the required reload values and the deviation errors compared to the intended baudrate ASCO Baudrate Generation Baud Rate SOBRS 0 fopy 16 MHz SOBRS 1 fopy 16 MHz Deviation Error Reload Value Deviation Error Reload Value 500 KBaud 0 0 0000 19 2 KBaud 0 2 3 5 0019 001A 2 1 3 5 0010 0011 9600 Baud 0 2 1 7 00334 00344 2 1 0 8 0021 0022 4800 Baud 0 2 0 8 0067 0068 0 6 0 8 0044 0045 2400 Baud 0 296 0 3 00CF 00DO 0 626 0 196 0089 008A 1200 Baud 0 496 0 1 019F 01A0 0 3 0 1 0114 0115 600 Baud 0 026 0 1 0340 0341 0 1 0 1 022A 022B 61 Baud 0 196 1FFF 0 026 0 0 115B 115C Note The deviation errors given in the table above are rounded Using a baudrate crystal e g 18 432 MHz will provide correct baudrates without deviation errors Synchronous Mode Baud Rates For synchronous operation the baud rate generator provides a clock with 4 times the rate of the established baud rate The baud rate for synchronous operation of serial channel ASCO can be determined by the following formula foru 4 X 2 SOBRS x lt SOBRL gt 1 foru BRES To LSR SEL S0 G x 2 lt SOBRS gt X Bsync
307. ord wise Note All GPRs are bit addressable independent of the allocation of the register bank via the context pointer CP Even GPRs which are allocated to not bit addressable RAM locations provide this feature The read modify write approach may be critical with hardware effected bits In these cases the hardware may change specific bits while the read modify write operation is in progress where the writeback would overwrite the new bit value generated by the hardware The solution is either the implemented hardware protection see below or realized through special programming see Particular Pipeline Effects Protected bits are not changed during the read modify write sequence i e when hardware sets e g an interrupt request flag between the read and the write of the read modify write sequence The hardware protection logic guarantees that only the intended bit s is are effected by the write back operation Note If a conflict occurs between a bit manipulation generated by hardware and an intended software access the software access has priority and determines the final value of the respective bit A summary of the protected bits implemented in the C161RI can be found at the end of chapter Architectural Overview Semiconductor Group 4 9 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI 4 3 Instruction State Times Basically the time to execute an instruction depends on where the instruction is fetched from a
308. ority 3 channel 7 1111 10 CPU interrupt PEC service level 15 group priority 2 channel 6 1110 10 CPU interrupt PEC service level 14 group priority 2 channel 2 1101 10 CPU interrupt CPU interrupt level 13 group priority 2 level 13 group priority 2 0001 11 CPU interrupt CPU interrupt level 1 group priority 3 level 1 group priority 3 0001 00 CPU interrupt CPU interrupt level 1 group priority O level 1 group priority O 0000 XX No service No service Note All requests on levels 13 1 cannot initiate PEC transfers They are always serviced by an interrupt service routine No PECC register is associated and no COUNT field is checked Interrupt Control Functions in the PSW The Processor Status Word PSW is functionally divided into 2 parts the lower byte of the PSW basically represents the arithmetic status of the CPU the upper byte of the PSW controls the interrupt system of the C161RI and the arbitration mechanism for the external bus interface Note Pipeline effects have to be considered when enabling disabling interrupt requests via modifications of register PSW see chapter The Central Processing Unit Semiconductor Group 5 8 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI PSW FF10 88 SFR Reset Value 0000 15 14 13 12 11 0 10 9 8 7 6 5 4 3 2 1 HLD MUL rw rw rw rw rw rw rw rw rw rw Bit Function N C V Z E CPU status flags Described in secti
309. ort 2 Alternate Functions of Port 3 Alternate Functions of Port 4 Alternate Functions of Port 5 Alternate Functions of Port 6 Dedicated Pins The External Bus Interface External Bus Modes Programmable Bus Characteristics READY Controlled Bus Cycles Controlling the External Bus Controller EBC Idle State The XBUS Interface The General Purpose Timer Units Timer Block GPT1 GPT1 Core Timer T3 GPT1 Auxiliary Timers T2 and T4 Interrupt Control for GPT1 Timers Timer Block GPT2 GPT2 Core Timer T6 GPT2 Auxiliary Timer T5 Interrupt Control for GPT2 Timers and CAPREL The Asynchronous Synchronous Serial Interface Asynchronous Operation Synchronous Operation Hardware Error Detection Capabilities ASCO Baud Rate Generation ASCO Interrupt Control The High Speed Synchronous Serial Interface Full Duplex Operation Half Duplex Operation Baud Rate Generation Error Detection Mechanisms SSC Interrupt Control The Watchdog Timer WDT Operation of the Watchdog Timer Reset Source Indication Semiconductor Group 1998 05 01 SIEMENS G16 1R General Information Table of Contents Page 14 The Real Time Clock ssseseeeeeeel eere 14 1 14 1 RTC Interrupt Generation 24 cosi erento eee ee hae Pe ee EE 14 3 15 The Bootstrap Loader 2 ee de oie eRe det ait bes 15 1 16 The Analog Digital Converter 0 000 cece 16 1 16 1 Mode Selection and Operation 02 00 eee ees 16 3 16 2 Conversion Timing C
310. ose IO when none of the BUSCON registers selects a demultiplexed bus mode Disable Enable Control for Pin BHE BYTDIS Bit BYTDIS is provided for controlling the active low Byte High Enable BHE pin The function of the BHE pin is enabled if the BYTDIS bit contains a 0 Otherwise it is disabled and the pin can be used as standard IO pin The BHE pin is implicitly used by the External Bus Controller to select one of two byte organized memory chips which are connected to the C161RI via a word wide external data bus After reset the BHE function is automatically enabled BYTDIS 0 if a 16 bit data bus is selected during reset otherwise it is disabled BYTDIS 1 It may be disabled if byte access to 16 bit memory is not required and the BHE signal is not used Semiconductor Group 9 7 1998 06 01 SIEMENS The External Bus Interface C161RI Segment Address Generation During external accesses the EBC generates a programmable number of address lines on Port 4 which extend the 16 bit address output on PORTO or PORT1 and so increase the accessible address space The number of segment address lines is selected during reset and coded in bit field SALSEL in register RPOH see table below SALSEL Segment Address Lines Directly accessible Address Space 11 Two A17 A16 256 KByte Default without pull downs 10 Seven A22 A16 8 MByte Maximum 0 1 None 64 KByte Minimum 00 Four A19 A16 1 MByte
311. ote Register bit P3 14 is not connected to an IO pin DP3 FFC6 E3 SFR Reset Value 0000 15 14 1 11 0 3 12 10 9 8 7 6 5 4 3 2 1 DP3 DP3 DP3 11 8 7 rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw Bit Function DP3 y Port direction register DP3 bit y DP3 y 0 Port line P3 y is an input high impedance DP3 y 1 Port line P3 y is an output ODP3 F1C6 E3 ESFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ODP3 ODP3 ODP3 ODP3 ODP3 ODP3 10 9 8 7 6 4 rw rw rw rw rw rw rw rw rw rw rw rw rw Bit Function ODP3 y Port 3 Open Drain control register bit y ODP3 y 0 Port line P3 y output driver in push pull mode ODP3 y 1 Port line P3 y output driver in open drain mode Semiconductor Group 7 15 1998 05 01 SIEMENS Parallel Ports C161RI Alternate Functions of Port 3 The pins of Port 3 serve for various functions which include external timer control lines the two serial interfaces one IC Bus interface and the control lines BHE WRH and CLKOUT The table below summarizes the alternate functions of Port 3 Port 3 Pin Alternate Function P3 0 SCLO FC Bus Clock Line O open drain only P3 1 SDAO FC Bus Data Line 0 open drain only P3 2 CAPIN GPT2 Capture Input P3 3 TSOUT Timer 3 Toggle Latch Output P3 4 T3EUD Timer 3 External Up Down Input P3 5 T4IN Timer 4 Count Input P3 6 T3IN Timer 3 Count Input P3 7 T2IN Timer 2 Count Input P3 8 MRST SSC Ma
312. ould be held high or low for at least 8 fopy cycles before it changes Semiconductor Group 10 7 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timer 3 in Incremental Interface Mode Incremental Interface mode for the core timer T3 is selected by setting bit field T3M in register T3CON to 110 In incremental interface mode the two inputs associated with timer T3 T3IN T3EUD are used to interface to an incremental encoder T3 is clocked by each transition on one or both of the external input pins which gives 2 fold or 4 fold resolution of the encoder input Figure 10 6 Block Diagram of Core Timer T3 in Incremental Interface Mode Bitfield T3l in control register T3CON selects the triggering transitions see table below In this mode the sequence of the transitions of the two input signals is evaluated and generates count pulses as well as the direction signal So T3 is modified automatically according to the speed and the direction of the incremental encoder and its contents therefore always represent the encoder s current position GPT1 Core Timer T3 Incremental Interface Mode Input Edge Selection T3I Triggering Edge for Counter Increment Decrement 000 None Counter T3 stops 001 Any transition rising or falling edge on T3IN 010 Any transition rising or falling edge on T3EUD 011 Any transition rising or falling edge on any T3 input T3IN or T3EUD 1XX Reserved Do not use
313. outputs the system clock signal BYTDIS Disable Enable Control for Pin BHE Set according to data bus width 0 Pin BHE enabled 1 Pin BHE disabled pin may be used for general purpose IO ROMEN Internal ROM Enable Set according to pin EA during reset 0 Internal ROM disabled accesses to the ROM area use the external bus 1 Internal ROM enabled SGTDIS Segmentation Disable Enable Control 0 Segmentation enabled CSP and IP are saved restored during interrupt entry exit 1 Segmentation disabled Only IP is saved restored ROMS1 Internal ROM Mapping 0 Internal ROM area mapped to segment 0 00 0000 00 7FFF 1 Internal ROM area mapped to segment 1 01 0000 01 7F FF STKSZ System Stack Size Selects the size of the system stack in the internal RAM from 32 to 1024 words Note Register SYSCON cannot be changed after execution of the EINIT instruction The function of bits XPER SHARE VISIBLE WRCFG BYTDIS ROMEN and ROMS is described in more detail in chapter The External Bus Controller Semiconductor Group 4 12 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI System Clock Output Enable CLKEN The system clock output function is enabled by setting bit CLKEN in register SYSCON to 1 If enabled port pin P3 15 takes on its alternate function as CLKOUT output pin The clock output is a 50 duty cycle clock except for direct drive operation where CLKOUT reflects the clock input signal and fo
314. ovide support for uninterruptable code sequences e g for semaphore operations They also support data addressing beyond the limits of the current DPPs except ATOMIC which is advantageous for bigger memory models in high level languages Refer to chapter System Programming for examples Protected Instructions Some instructions of the C161RI which are critical for the functionality of the controller are implemented as so called Protected Instructions These protected instructions use the maximum instruction format of 32 bits for decoding while the regular instructions only use a part of it e g the lower 8 bits with the other bits providing additional information like involved registers Decoding all 32 bits of a protected doubleword instruction increases the security in cases of data distortion during instruction fetching Critical operations like a software reset are therefore only executed if the complete instruction is decoded without an error This enhances the safety and reliability of a microcontroller system Semiconductor Group 22 4 1998 05 01 SIEMENS Device Specification C161RI 23 Device Specification The device specification describes the electrical parameters of the device It lists DC characteristics like input output or supply voltages or currents and AC characteristics like timing characteristics and requirements Other than the architecture the instruction set or the basic functions of the C161RI core and its per
315. pace All of the physically separated memory areas including internal ROM Flash OTP where integrated internal RAM the internal Special Function Register Areas SFRs and ESFRs the address areas for integrated XBUS peripherals and external memory are mapped into one common address space The C161RI provides a total addressable memory space of 16 MBytes This address space is arranged as 256 segments of 64 KBytes each and each segment is again subdivided into four data pages of 16 KBytes each see figure below FF FFFF 254 129 OT FFFF 80 0000 i 125 65 400000 X B oreem VN CNECAE 2 OA FFFF S 0170000 9500001 Data Page 3 Z Data Page 2 04 F FF 7 8 01 FFFF 0070000 00 0000 Total Address Space Segments 1 and 0 16 MByte Segments 255 0 64 64 KByte Figure 3 1 Address Space Overview Semiconductor Group 3 1 1998 05 01 SIEMENS Memory Organization C161RI Most internal memory areas are mapped into segment 0 the system segment The upper 4 KByte of segment 0 00 F000 OO FFFF hold the Internal RAM and Special Function Register Areas SFR and ESFR The lower 32 KByte of segment 0 000000 00 7FFF may be occupied by a part of the on chip ROM Flash OTP memory and is called the Internal ROM area This ROM area can be remapped to segment 1 01 0000 01 7FFF j to enable external memory access in the lower ha
316. perands Any word data access is made to an even byte address For PEC data transfers the external memory in segment 0 can be accessed independent of the contents of the DPP registers via the PEC source and destination pointers The external memory is not provided for single bit storage and therefore it is not bit addressable Semiconductor Group 3 10 1998 05 01 SIEMENS Memory Organization C161RI 3 5 Crossing Memory Boundaries The address space of the C161RI is implicitly divided into equally sized blocks of different granularity and into logical memory areas Crossing the boundaries between these blocks code or data or areas requires special attention to ensure that the controller executes the desired operations Memory Areas are partitions of the address space that represent different kinds of memory if provided at all These memory areas are the internal RAM SFR area the internal ROM Flash OTP if available the on chip X Peripherals if integrated and the external memory Accessing subsequent data locations that belong to different memory areas is no problem However when executing code the different memory areas must be switched explicitly via branch instructions Sequential boundary crossing is not supported and leads to erroneous results Note Changing from the external memory area to the internal RAM SFR area takes place within segment 0 Segments are contiguous blocks of 64 KByte each They are referenced via the
317. pheral interrupt source and the interrupt vector of this source will be used to service the external interrupt request Note In order to use any of the listed pins as external interrupt input it must be switched to input mode via its direction control bit DPx y in the respective port direction control register DPx Pins to be used as External Interrupt Inputs Port Pin Original Function Control Register P2 15 8 EX7 0IN Fast external interrupt input pin EXICON P3 7 T2IN Auxiliary timer T2 input pin T2CON P3 5 TAIN Auxiliary timer T4 input pin T4CON P3 2 CAPIN GPT2 capture input pin T5CON Pins T2IN or T4IN can be used as external interrupt input pins when the associated auxiliary timer T2 or T4 in block GPT 1 is configured for capture mode This mode is selected by programming the mode control fields T2M or T4M in control registers T2CON or T4CON to 101 The active edge of the external input signal is determined by bit fields T21 or T4l When these fields are programmed to X01 interrupt request flags T2IR or T4IR in registers T2IC or T4IC will be set on a positive external transition at pins T2IN or TAIN respectively When T2l or T4l are programmed to X105 then a negative external transition will set the corresponding request flag When T2l or T4l are programmed to X11 both a positive and a negative transition will set the request flag In all three cases the contents of the core timer T3 will be captured into the auxi
318. pin TxDO alternate function of P3 10 will be switched to output mode after the reception of the zero byte All other pins remain in the high impedance state until they are changed by software or peripheral operation Semiconductor Group 18 6 1998 06 01 SIEMENS System Reset C161RI Application Specific Initialization Routine After the internal reset condition is removed the C161RI fetches the first instruction from location 00 0000 which is the first vector in the trap interrupt vector table the reset vector 4 words locations 00 0000 through 00 0006 are provided in this table to start the initialization after reset As a rule this location holds a branch instruction to the actual initialization routine that may be located anywhere in the address space Note When the Bootstrap Loader Mode was activated during a hardware reset the C161RI does not fetch instructions from location 00 0000 but rather expects data via serial interface ASCO If single chip mode is selected during reset the first instruction is fetched from the internal ROM OTP Flash Otherwise it is fetched from external memory When internal ROM access is enabled after reset in single chip mode bit ROMEN 1 in register SYSCON the software initialization routine may enable and configure the external bus interface before the execution of the EINIT instruction When external access is enabled after reset it may be desirable to reconfigure the external bus
319. pt Enable bit allows to globally enable IEN 1 or disable IEN 0 interrupts The four bit Interrupt Level field ILVL specifies the priority of the current CPU activity The interrupt level is updated by hardware upon entry into an interrupt service routine but it can also be modified via software to prevent other interrupts from being acknowledged In case an interrupt level 15 has been assigned to the CPU it has the highest possible priority and thus the current CPU operation cannot be interrupted except by hardware traps or external non maskable interrupts For details please refer to chapter Interrupt and Trap Functions After reset all interrupts are globally disabled and the lowest priority ILVL 0 is assigned to the initial CPU activity The Instruction Pointer IP This register determines the 16 bit intra segment address of the currently fetched instruction within the code segment selected by the CSP register The IP register is not mapped into the C161RI s address space and thus it is not directly accessable by the programmer The IP can however be modified indirectly via the stack by means of a return instruction The IP register is implicitly updated by the CPU for branch instructions and after instruction fetch operations IP Reset Value 00004 15 14 13 12 1 10 9 8 7 6 5 4 3 2 0 Bit Function ip Specifies the intra segment offset from where the current instruction is to be f
320. pt or PEC requests will be acknowledged while an exception trap service routine is executed Note The TRAP instruction does not change the CPU level so software invoked trap service routines may be interrupted by higher requests Interrupt Enable bit IEN globally enables or disables PEC operation and the acceptance of interrupts by the CPU When IEN is cleared no new interrupt requests are accepted by the CPU Requests that already have entered the pipeline at that time will process however When IEN is set to 1 all interrupt sources which have been individually enabled by the interrupt enable bits in their associated control registers are globally enabled Note Traps are non maskable and are therefore not affected by the IEN bit Semiconductor Group 5 9 1998 05 01 Interrupt and Trap Functions C161RI SIEMENS 5 2 Operation of the PEC Channels The C161RI s Peripheral Event Controller PEC provides 8 PEC service channels which move a single byte or word between two locations in segment 0 data pages 3 0 This is the fastest possible interrupt response and in many cases is sufficient to service the respective peripheral request e g serial channels etc Each channel is controlled by a dedicated PEC Channel Counter Control register PECCx and a pair of pointers for source SRCPx and destination DSTPx of the data transfer The PECC registers control the action that is performed by the respective PEC channel PE
321. quired to pull POL 4 low but also pins POL 2 POL 3 POL 5 must receive defined levels This is described in chapter System Reset Semiconductor Group 15 3 1998 05 01 SIEMENS The Bootstrap Loader C161RI Memory Configuration after Reset The configuration i e the accessibility of the C161RI s memory areas after reset in Bootstrap Loader mode differs from the standard case Pin EA is not evaluated when BSL mode is selected and accesses to the internal code memory are partly redirected while the C161RI is in BSL mode see table below All code fetches are made from the special Boot ROM while data accesses read from the internal code memory Data accesses will return undefined values on ROMless devices Note The code in the Boot ROM is not an invariant feature of the C161RI User software should not try to execute code from the internal ROM area while the BSL mode is still active as these fetches will be redirected to the Boot ROM The Boot ROM will also move to segment 1 when the internal ROM area is mapped to segment 1 LO i e i access to external bus disabled int RAM O Teke to p int ROM 9 enabled a access to external bus enabled int RAM O access to T int ROM 9 enabled ta Depends on reset config EA PO BSL mode active Yes POL 4 0 Yes POL 4 0 No POL 4 1 EA pin high low acc to applicat
322. r from overflowing during Idle mode it must be programmed to a reasonable time interval before Idle mode is entered Semiconductor Group 19 3 1998 05 01 SIEMENS Power Management C161RI 19 2 Power Down Mode To further reduce the power consumption the microcontroller can be switched to Power Down mode Clocking of all internal blocks is stopped RTC and selected oscillator optionally the contents of the internal RAM however are preserved through the voltage supplied via the Vpp pins The watchdog timer is stopped in Power Down mode This mode can only be terminated by an external hardware reset i e by asserting a low level on the RSTIN pin This reset will initialize all SFRs and ports to their default state but will not change the contents of the internal RAM There are two levels of protection against unintentionally entering Power Down mode First the PWRDN Power Down instruction which is used to enter this mode has been implemented as a protected 32 bit instruction Second this instruction is effective only if the NMI Non Maskable Interrupt pin is externally pulled low while the PWRDN instruction is executed The microcontroller will enter Power Down mode after the PWRDN instruction has completed This feature can be used in conjunction with an external power failure signal which pulls the NMI pin low when a power failure is imminent The microcontroller will enter the NMI trap routine which can save the internal state into RA
323. r 2 Interrupt Control Register 0000 T3IC b FF62 B1 GPT1 Timer 3 Interrupt Control Register 0000 Semiconductor Group 21 11 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value T4IC b FF64 B2 GPT1 Timer 4 Interrupt Control Register 0000 T5IC b FF66 B3 GPT2 Timer 5 Interrupt Control Register 0000 T6IC b FF68 B4 GPT2 Timer 6 Interrupt Control Register 0000 CRIC b FF6A B5 GPT2 CAPREL Interrupt Control Register 0000 SOTIC b FF6C B6 Serial Channel 0 Transmit Interrupt Control 0000 Register SORIC b FF6E B7 Serial Channel 0 Receive Interrupt Control 0000 Register SOEIC b FF70 B8 Serial Channel 0 Error Interrupt Control Register 0000 SSCTIC b FF72 B9 SSC Transmit Interrupt Control Register 0000 SSCRIC b FF74 BA SSC Receive Interrupt Control Register 0000 SSCEIC b FF76 BB SSC Error Interrupt Control Register 0000 CC8IC b FF88 CA CAPCOM Register 8 Interrupt Control Register 0000 CC9IC b FF8A C5 CAPCOM Register 9 Interrupt Control Register 0000 CC10IC b FF8C C6 CAPCOM Register 10 Interrupt Control Register 0000 CC11IC b FF8E C7 CAPCOM Register 11 Interrupt Control Register 0000 CC121C b FF90 C8 External Interrupt 4 Control Register 0000 CC13IC b FF92 C9 External Interrupt 5 Control Register 0000 CC14IC b FF9
324. r ADDRSEL1 The hardwired XADRSx registers are defined non overlapping Semiconductor Group 9 23 1998 06 01 SIEMENS The External Bus Interface C161RI RPOH F108 84 SFR Reset Value XX 15 14 13 42 11 10 9 8 7 6 5 4 3 2 1 0 CLKCFG SALSEL CSSEL r r r r Bit Function WRC Write Configuration 0 Pins WR and BHE operate as WRL and WRH signals 1 Pins WR and BHE operate as WR and BHE signals CSSEL Chip Select Line Selection Number of active CS outputs 00 3 CS lines CS2 CS0 01 2 CS lines CS1 CSO 10 No CS lines at all 11 5 CS lines CS4 CSO Default without pulldowns SALSEL Segment Address Line Selection Number of active segment address outputs 00 4 bit segment address A19 A16 01 No segment address lines at all 10 6 bit segment address A21 A16 11 2 bit segment address A17 A16 Default without pulldowns CLKCFG Clock Generation Mode Configuration These pins define the clock generation mode i e the mechanism how the internal CPU clock is generated from the externally applied XTAL1 input clock Note RPOH cannot be changed via software but rather allows to check the current configuration Precautions and Hints The external bus interface is enabled as long as at least one of the BUSCON registers has its BUSACT bit set PORT will output the intra segment address as long as at least one of the BUSCON registers selects a demultiplexed externa
325. r Group 24 2 1998 05 01 SIEMENS Keyword Index C161RI Interrupt Enable Disable 5 13 External 5 21 Fast external 5 22 Node Sharing 5 20 Priority 5 6 Processing 5 1 5 5 Response Times 5 16 RTC 14 3 Sources 5 3 System 2 6 5 2 Vectors 5 3 IP 4 17 IRAM 3 4 ISNC 5 20 L Latched chip select 9 9 M Management Peripheral 19 10 Power 19 1 Master mode lC Bus 17 6 MDC 4 28 MDH 4 27 MDL 4 27 Memory 2 7 bit addressable 3 5 Code memory handling 20 14 External 3 10 RAM SFR 3 4 ROM 3 3 Tri state time 9 13 XRAM 3 9 Memory Cycle Time 9 12 Multimaster mode lC Bus 17 6 Multiplexed Bus 9 3 Multiplication 4 27 20 1 N NMI 5 1 5 26 O ODP2 7 12 Semiconductor Group ODP3 7 15 ODP6 7 26 ONES 4 29 Open Drain Mode 7 2 Oscillator circuitry 6 2 OTP Handling 20 14 P POL POH 7 6 P1L P1H 7 9 P2 7 12 P3 7 15 P4 7 20 P5 7 23 P5DIDIS 7 24 P6 7 26 PEC 2 7 3 7 5 10 Response Times 5 18 PECCx 5 10 Peripheral Enable Disable 19 11 Management 19 10 Summary 2 9 PICON 7 3 Pins 8 1 23 2 23 3 in Idle and Power Down mode 19 5 Pipeline 4 3 Effects 4 6 PLL 18 13 Port 2 10 input threshold 7 3 Power Down Mode 19 4 Power Management 2 14 19 1 Prescaler 6 4 Protected Bits 2 15 4 9 instruction 22 4 PSW 4 14 5 8 R RAM extension 3 9 internal 3 4 Read Write Delay 9 14 READY 9 15 24 3 1998 05 01 SIEMENS Keyword Index C161RI Real Time Clock gt RTC 14 1 Registers 21 1 sorted by addr
326. r Rw Rw Post increment Index Register Indirect Addressing Used to pop one byte or word from a user stack This mode is available to most instructions but only GPRs RO R3 can be specified as the user stack pointer Rb Rw or Rw Rw Post increment Indirect Addressing Used to pop one byte or word from a user stack This mode is only available for MOV instructions and can specify any GPR as the user stack pointer 20 2 Register Banking Register banking provides the user with an extremely fast method to switch user context A single machine cycle instruction saves the old bank and enters a new register bank Each register bank may assign up to 16 registers Each register bank should be allocated during coding based on the needs of each task Once the internal memory has been partitioned into a register bank space internal stack space and a global internal memory area each bank pointer is then assigned Thus upon entry into a new task the appropriate bank pointer is used as the operand for the SCXT switch context instruction Upon exit from a task a simple POP instruction to the context pointer CP restores the previous task s register bank 20 3 Procedure Call Entry and Exit To support modular programming a procedure mechanism is provided to allow coding of frequently used portions of code into subroutines The CALL and RET instructions store and restore the value of the instruction pointer IP on the system stack before and afte
327. r a subroutine is executed Procedures may be called conditionally with instructions CALLA or CALLI or be called unconditionally using instructions CALLR or CALLS Note Any data pushed onto the system stack during execution of the subroutine must be popped before the RET instruction is executed Semiconductor Group 20 8 1998 05 01 SIEMENS System Programming C161RI Passing Parameters on the System Stack Parameters may be passed via the system stack through PUSH instructions before the subroutine is called and POP instructions during execution of the subroutine Base plus offset indirect addressing also permits access to parameters without popping these parameters from the stack during execution of the subroutine Indirect addressing provides a mechanism of accessing data referenced by data pointers which are passed to the subroutine In addition two instructions have been implemented to allow one parameter to be passed on the system stack without additional software overhead The PCALL push and call instruction first pushes the reg operand and the IP contents onto the system stack and then passes control to the subroutine specified by the caddr operand When exiting from the subroutine the RETP return and pop instruction first pops the IP and then the reg operand from the system stack and returns to the calling program Cross Segment Subroutine Calls Calls to subroutines in different segments require the use of the
328. r flag SSCTE and when enabled via SSCTEN the error interrupt request flag SSCEIR If a transfer starts while the transmit buffer is not updated the slave will shift out the old contents of the shift register which normally is the data received during the last transfer This may lead to the corruption of the data on the transmit receive line in half duplex mode open drain configuration if this slave is not selected for transmission This mode requires that slaves not selected for transmission only shift out ones i e their transmit buffers must be loaded with FFFF prior to any transfer Note A slave with push pull output drivers which is not selected for transmission will normally have its output drivers switched However in order to avoid possible conflicts or misinterpretations it is recommended to always load the slave s transmit buffer prior to any transfer Register SSCCON Register SSCEIR SSCTE P Transmit Eng SSCTE SSCRE SSCEIE Error heee y SSCRE Interrupt SSCEIR SSCEINT SSCPE ie Phase Err PENES d SSCPE SSCBE ps Baudrate Error SSCBE MCS01968 Figure 12 6 SSC Error Interrupt Control Semiconductor Group 12 13 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI 12 5 SSC Interrupt Control Three bit addressable interrupt control registers are provided for serial channel SSC Register SSCTIC controls the transmit interrupt SSCRIC controls the re
329. r of the C161RI provides a mechanism to load the startup program which is executed after reset via the serial interface In this case no external memory or an internal ROM OTP Flash is required for the initialization code starting at location 00 0000 The bootstrap loader moves code data into the internal RAM but it is also possible to transfer data via the serial interface into an external RAM using a second level loader routine ROM memory internal or external is not necessary However it may be used to provide lookup tables or may provide core code i e a set of general purpose subroutines e g for IO operations number crunching system initialization etc 32 bytes 6 Int Boot ROM BSL routine user software BSL initialization time gt 2 us fopy 20 MHz 2 Zero byte 1 start bit eight 0 data bits 1 stop bit sent by host 3 Identification byte sent by C161RI 32 bytes of code data sent by host 5 Caution TxDO is only driven a certain time after reception of the zero byte 2 5 us fopy 20 MHz 9 Internal Boot ROM Figure 15 1 Bootstrap Loader Sequence The Bootstrap Loader may be used to load the complete application software into ROMless systems it may load temporary software into complete systems for testing or calibration it may also be used to load a programming routine for Flash devices The BSL mechanism may be used for standard system startup as well as only for special occa
330. r slowdown operation where CLKOUT mirrors the CPU clock signal whose frequency equals the CPU operating frequency four fcpy Note The output driver of port pin P3 15 is switched on automatically when the CLKOUT function is enabled The port direction bit is disregarded After reset the clock output function is disabled CLKEN 0 In emulation mode the CLKOUT function is enabled automatically Segmentation Disable Enable Control SGTDIS Bit SGTDIS allows to select either the segmented or non segmented memory mode In non segmented memory mode SGTDIS 1 it is assumed that the code address space is restricted to 64 KBytes segment 0 and thus 16 bits are sufficient to represent all code addresses For implicit stack operations CALL or RET the CSP register is totally ignored and only the IP is saved to and restored from the stack In segmented memory mode SGTDIS 0 it is assumed that the whole address space is available for instructions For implicit stack operations CALL or RET the CSP register and the IP are saved to and restored from the stack After reset the segmented memory mode is selected Note Bit SGTDIS controls if the CSP register is pushed onto the system stack in addition to the IP register before an interrupt service routine is entered and it is repopped when the interrupt service routine is left again System Stack Size STKSZ This bitfield defines the size of the physical system stack which is loca
331. r the auxiliary timer T5 is selected by setting bit field T5M in register T5CON to 001 In counter mode timer T5 can be clocked by a transition of timer T6 s output toggle latch T6OTL i e timer concatenation The event causing an increment or decrement of the timer can be a positive a negative or both a positive and a negative transition at the toggle latch T6OTL Bit field T5lI in control register T5CON selects the triggering transition see table below GPT2 Auxiliary Timer Counter Mode Input Edge Selection T5l Triggering Edge for Counter Increment Decrement X00 None Counter T5 is disabled 001 Reserved Do not use this combination 010 Reserved Do not use this combination 011 Reserved Do not use this combination 101 Positive transition rising edge of output toggle latch TGOTL 110 Negative transition falling edge of output toggle latch T6OTL 111 Any transition rising or falling edge of output toggle latch T6OTL Note Only state transitions of TGOTL which are caused by the overflows underflows of T6 will trigger the counter function of T5 Modifications of TGOTL via software will NOT trigger the counter function of T5 Semiconductor Group 10 24 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timer Concatenation Using the toggle bit TEOTL as a clock source for the auxiliary timer in counter mode concatenates the core timer T6 with the auxiliary timer Depending on whi
332. rating modes to deactivate CPU port drivers and control logic Idle Power Down This enables the application i e the programmer to choose the optimum constellation for each operating condition so the power consumption can be adapted to conditions like maximum performance partial performance intermittend operation or standby Intermittend operation i e alternating phases of high performance and power saving is supported by the cyclic interrupt generation mode of the on chip RTC real time clock p at QE E a ea No of act Peripherals ui dde dE ede ume deu ceo eme f e aei Eur e rr Mu em cum xem cux jme imum mpi cues umb Tem ex dent cnr ven aM Figure 19 1 Power Reduction Possibilities Semiconductor Group 19 1 1998 05 01 SIEMENS Power Management C161RI These three means described above can be applied independent from each other and thus provide a maximum of flexibility for each application For the basic power reduction modes Idle Power Down there are dedicated instructions while special registers control clock generation SYSCON2 and peripheral management SYSCON3 Two different general power reduction modes with different levels of power reduction have been implemented in the C161RI which may be entered under software control In Idle mode the CPU is stopped while the enabled peripherals continue their operation Idle mode can be terminated by any reset or interrupt request In Power Down
333. ration This XBUS is an internal representation of the external bus interface that opens and simplifies the integration of peripherals by standardizing the required interface One representative taking advantage of this technology is the integrated CAN module The C165 type devices are reduced versions of the C167 which provide a smaller package and reduced power consumption at the expense of the A D converter the CAPCOM units and the PWM module The C164 type devices and some of the C161 type devices are further enhanced by a flexible power management and form the third generation of the 16 bit controller family This power management mechanism provides effective means to control the power that is consumed in a certain state of the controller and thus allows the minimization of the overall power consumption with respect to a given application Semiconductor Group 1 2 1998 05 01 SIEMENS Introduction C161RI A variety of different versions is provided which offer various kinds of on chip program memory mask programmable ROM e Flash memory OTP memory ROMless with no non volatile memory at all Also there are devices with specific functional units The devices may be offered in different packages temperature ranges and speed classes More standard and application specific derivatives are planned and in development Note Not all derivatives will be offered in any temperature range speed class package or program memory var
334. ration of the internal reset sequence After that it is released and is then controlled by the external circuitry alone The bidirectional reset function is useful in applications where external devices require a defined reset signal but cannot be connected to the C161RHI s RSTOUT signal e g an external flash memory which must come out of reset and deliver code well before HS TOUT can be deactivated via EINIT Semiconductor Group 8 2 1998 05 01 SIEMENS Dedicated Pins C161RI The following behavior differences must be observed when using the bidirectional reset feature in an application e Bit BDRSTEN in register SYSCON cannot be changed after EINIT and is cleared automatically after a reset The reset indication flags always indicate a long hardware reset e The PORTO configuration is treated like on a hardware reset Especially the bootstrap loader may be activated when POL 4 is low e Pin RSTIN may only be connected to external reset devices with an open drain output driver A short hardware reset is extended to the duration of the internal reset sequence The Reset Output RSTOUT provides a special reset signal for external circuitry RSTOUT is activated at the beginning of the reset sequence triggered via RSTIN a watchdog timer overflow or by the SRST instruction RSTOUT remains active low until the EINIT instruction is executed This allows to initialize the controller before the external circuitry is activated Note
335. rea within the internal RAM that effectively is used for standard stack operations is defined via bitfield STKSZ in register SYSCON see below lt STKSZ gt Stack Size Internal RAM Addresses Words Significant Bits of Words of Physical Stack Stack Pointer SP 000 256 00 FBFE 00 FA00 Default after Reset SP 8 SP 0 0015 128 00 FBFE 00 FBOO SP SPO 010 64 00 FBFE 00 FB80 SP 6 SP 0 0115 32 00 FBFE 00 FBCO SP 5 SP 100 512 00 FBFE 00 F800 not for 1KByte IRAM SP 9 SP 0 101 Sa Reserved Do not use this combination aaa 110 ex Reserved Do not use this combination 11158 1024 00 FDFE 00 FX00 Note No circular stack SP 11 SP 0 00 FXO00 represents the lower IRAM limit i e 1 KB 00 FA00 2 KB 00 F600 3 KB 00 F200 The virtual stack addresses are transformed to physical stack addresses by concatenating the significant bits of the stack pointer register SP see table with the complementary most significant bits of the upper limit of the physical stack area 00 FBFE This transformation is done via hardware see figure below The reset values STKOV FA00 STKUN FCOO SP FC00 STKSZ 000 map the virtual stack area directly to the physical stack area and allow using the internal system stack without any changes provided that the 256 word area is not exceeded Semiconductor Group 20 5 1998 05 01 S
336. reception of data is double buffered A 16 bit baud rate generator provides the SSC with a separate serial clock signal The high speed synchronous serial interface can be configured in a very flexible way so it can be used with other synchronous serial interfaces e g the ASCO in synchronous mode serve for master slave or multimaster interconnections or operate compatible with the popular SPI interface So it can be used to communicate with shift registers IO expansion peripherals e g EEPROMs etc or other controllers networking The SSC supports half duplex and full duplex communication Data is transmitted or received on pins MTSR P3 9 Master Transmit Slave Receive and MRST P3 8 Master Receive Slave Transmit The clock signal is output or input on pin SCLK P3 13 These pins are alternate functions of Port 3 pins Ports amp Direction Control Data Registers Control Registers Interrupt Control Alternate Functions SSCCON SSCTIC SSCRIC SSCEIC SCLK P3 13 MTSR P3 9 MRST P3 8 ODP3 Port 3 Open Drain Control Register DP3 Port 3 Direction Control Register P3 Port 3 Data Register SSCBR SSC Baud Rate Generator Reload Register SSCCON SSC Control Register SSCTB SSC Transmit Buffer Register SSCRB SSC Receive Buffer Register SSCTIC SSC Transmit Interrupt Control Register SSCRIC SSC Receive Interrupt Control Register SSCEIC SSC Error Interrupt Control Register Figure 12 1 SFRs and Port Pins associated
337. rial Channel ASCO and a High Speed Synchronous Serial Channel SSC The ASCO is upward compatible with the serial ports of the Siemens 8 bit microcontroller families and supports full duplex asynchronous communication at up to 500 KBaud and half duplex synchronous communication at up to 2 MBaud 16 MHz CPU clock A dedicated baud rate generator allows to set up all standard baud rates without oscillator tuning For transmission reception and error handling 4 separate interrupt vectors are provided In asynchronous mode 8 or 9 bit data frames are transmitted or received preceded by a start bit and terminated by one or two stop bits For multiprocessor communication a mechanism to distinguish address from data bytes has been included 8 bit data plus wake up bit mode In synchronous mode the ASCO transmits or receives bytes 8 bits synchronously to a shift clock which is generated by the ASCO The ASCO always shifts the LSB first A loop back option is available for testing purposes A number of optional hardware error detection capabilities has been included to increase the reliability of data transfers A parity bit can automatically be generated on transmission or be checked on reception Framing error detection allows to recognize data frames with missing stop bits An overrun error will be generated if the last character received has not been read out of the receive buffer register at the time the reception of a new character is complete
338. rity field IL VL Additionally the different interrupt sources are controlled individually by their specific interrupt control registers IC Thus the acceptance of requests by the CPU is determined by both the individual interrupt control registers and the PSW PEC services are controlled by the respective PECCx register and the source and destination pointers which specify the task of the respective PEC service channel Interrupt Control Registers All interrupt control registers are organized identically The lower 8 bits of an interrupt control register contain the complete interrupt status information of the associated source which is required during one round of prioritization the upper 8 bits of the respective register are reserved All interrupt control registers are bit addressable and all bits can be read or written via software This allows each interrupt source to be programmed or modified with just one instruction When accessing interrupt control registers through instructions which operate on word data types their upper 8 bits 15 8 will return zeros when read and will discard written data The layout of the Interrupt Control registers shown below applies to each xxIC register where xx stands for the mnemonic for the respective source Semiconductor Group 5 5 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI xxIC yyyy ZZ lt SFR area gt Reset Value 00 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
339. rning from the service routine Semiconductor Group 5 14 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI High Status of Addresses Interrupted Task AN NEVER aa NES 0 s IEEE ee OP je Low Addresses a System Stack before b System Stack after b System Stack after Interrupt Entry Interrupt Entry Interrupt Entry Unsegmented Segmented MCD02226 Figure 5 3 Task Status saved on the System Stack The interrupt request flag of the source that is being serviced is cleared The IP is loaded with the vector associated with the requesting source the CSP is cleared in case of segmentation and the first instruction of the service routine is fetched from the respective vector location which is expected to branch to the service routine itself The data page pointers and the context pointer are not affected When the interrupt service routine is left RETI is executed the status information is popped from the system stack in the reverse order taking into account the value of bit SGTDIS Context Switching An interrupt service routine usually saves all the registers it uses on the stack and restores them before returning The more registers a routine uses the more time is wasted with saving and restoring The C161RI allows to switch the complete bank of CPU registers GPRs with a single instruction so the service routine executes within its own separate context The instruction SCXT CP New_Bank pus
340. rolled by the ALECTLx bits in the BUSCON registers When bit ALECTL is set to 1 external bus cycles accessing the respective address window will have their ALE signal prolonged by half a CPU clock 1 TCL Also the address hold time after the falling edge of ALE will be prolonged by half a CPU clock so the data transfer within a bus cycle refers to the same CLKOUT edges as usual i e the data transfer is delayed by one CPU clock This allows more time for the address to be latched Note ALECTLO is 1 after reset to select the slowest possible bus cycle the other ALECTLx are 0 after reset Normal Multiplexed id Lengthened Multiplexed Bus Cycle Bus Cycle Segen Address Address P4 ALE N N lt a Setup Hold wor une XC Lus X Eme Ci em XC RD N N aus Po Mes MCD02235 Figure 9 6 ALE Length Control Semiconductor Group 9 11 1998 06 01 SIEMENS The External Bus Interface C161RI Programmable Memory Cycle Time The C161RI allows the user to adjust the controller s external bus cycles to the access time of the respective memory or peripheral This access time is the total time required to move the data to the destination It represents the period of time during which the controller s signals do not change we Bus Cycle Segment X Address 7 X ALE MCTC Wait State
341. roup 3 2 1998 05 01 SIEMENS Memory Organization C161RI 3 1 Internal ROM The C161RI may reserve an address area of variable size depending on the version for on chip mask programmable ROM Flash OTP memory organized as X x 32 The lower 32 KByte of this on chip memory block are referred to as Internal ROM Area Internal ROM accesses are globally enabled or disabled via bit ROMEN in register SYSCON This bit is set during reset according to the level on pin EA or may be altered via software If enabled the internal ROM area occupies the lower 32 KByte of either segment 0 or segment 1 This ROM mapping is controlled by bit ROMS1 in register SYSCON Note The size of the internal ROM area is independent of the size of the actual implemented ROM Also devices with less than 32 KByte of ROM or with no ROM at all will have this 32 KByte area occupied if the ROM is enabled Devices with larger ROMs provide the mapping option only for the ROM area Devices with a ROM size above 32 KByte expand the ROM area from the middle of segment 1 i e starting at address 01 8000 The internal ROM Flash can be used for both code instructions and data constants tables etc storage Code fetches are always made on even byte addresses The highest possible code storage location in the internal ROM is either xx xxFE for single word instructions or xx XxFC for double word instructions The respective location must contain a branch instru
342. routine within the current code segment Returning from a subroutine within any code segment Returning from a subroutine within the current code segment plus an additional popping of a selectable register from the system stack Returning from an interrupt service routine Semiconductor Group 22 3 JMPA JMPS JB JBC CALLA CALLR CALLS PCALL TRAP RET RETS RETP RETI JMPI JMPR JNB JNBS CALLI 1998 05 01 SIEMENS Instruction Set Summary C161RI System Control Instructions Resetting the C161RI via software SRST Entering the Idle mode IDLE Entering the Power Down mode PWRDN Servicing the Watchdog Timer SRVWDT Disabling the Watchdog Timer DISWDT Signifying the end of the initialization routine pulls pin RSTOUT high and disables the effect of any later execution of a DISWDT instruction EINIT Miscellaneous Null operation which requires 2 bytes of storage and the minimum time for execution NOP Definition of an unseparable instruction sequence ATOMIC Switch reg bitoff and bitaddr addressing modes to the Extended SFR space EXTR Override the DPP addressing scheme using a specific data page instead of the DPPs and optionally switch to ESFR space EXTP EXTPR Override the DPP addressing scheme using a specific segment instead of the DPPs and optionally switch to ESFR space EXTS EXTSR Note The ATOMIC and EXT instructions pr
343. rovides several mechanisms to manipulate bits These mechanisms either manipulate software flags within the internal RAM control on chip peripherals via control bits in their respective SFRs or control IO functions via port pins The instructions BSET BCLR BAND BOR BXOR BMOV BMOVN explicitly set or clear specific bits The instructions BFLDL and BFLDH allow to manipulate up to 8 bits of a specific byte at one time The instructions JBC and JNBS implicitly clear or set the specified bit when the jump is taken The instructions JB and JNB also conditional jump instructions that refer to flags evaluate the specified bit to determine if the jump is to be taken Note Bit operations on undefined bit locations will always read a bit value of 0 while the write access will not effect the respective bit location All instructions that manipulate single bits or bit groups internally use a read modify write sequence that accesses the whole word which contains the specified bit s This method has several consequences Bits can only be modified within the internal address areas i e internal RAM and SFRs External locations cannot be used with bit instructions The upper 256 bytes of the SFR area the ESFR area and the internal RAM are bit addressable see chapter Memory Organization i e those register bits located within the respective sections can be directly manipulated using bit instructions The other SFRs must be accessed byte w
344. rror detection enable bit SOPEN is set in the modes where a parity bit is received and the parity check on the received data bits proves false the parity error flag SOPE is set indicating that the error interrupt request is due to a parity error Asynchronous mode only Ifthe overrun error detection enable bit SOOEN is set and the last character received was not read out of the receive buffer by software or PEC transfer at the time the reception of a new frame is complete the overrun error flag SOOE is set indicating that the error interrupt request is due to an overrun error Asynchronous and synchronous mode 11 4 ASCO Baud Rate Generation The serial channel ASCO has its own dedicated 13 bit baud rate generator with 13 bit reload capability allowing baud rate generation independent of the GPT timers The baud rate generator is clocked with the CPU clock divided by 2 fcp 2 The timer is counting downwards and can be started or stopped through the Baud Rate Generator Run Bit SOR in register SOCON Each underflow of the timer provides one clock pulse to the serial channel The timer is reloaded with the value stored in its 13 bit reload register each time it underflows The resulting clock is again divided according to the operating mode and controlled by the Baudrate Selection Bit SOBRS If SOBRS 1 the clock signal is additionally divided to 2 3rd of its frequency see formulas and table So the baud rate of ASCO is determined by
345. ruction restores the system state from the system stack and then branches back to the location where the trap or interrupt occurred 20 8 Unseparable Instruction Sequences The instructions of the C161RI are very efficient most instructions execute in one machine cycle and even the multiplication and division are interruptable in order to minimize the response latency to interrupt requests internal and external In many microcontroller applications this is vital Some special occasions however require certain code sequences e g semaphore handling to be uninterruptable to function properly This can be provided by inhibiting interrupts during the respective code sequence by disabling and enabling them before and after the sequence The necessary overhead may be reduced by means of the ATOMIC instruction which allows locking 1 4 instructions to an unseparable code sequence during which the interrupt system standard interrupts and PEC requests and Class A Traps NMI stack overflow underflow are disabled A Class B Trap illegal opcode illegal bus access etc however will interrupt the atomic sequence since it indicates a severe hardware problem The interrupt inhibit caused by an ATOMIC instruction gets active immediately i e no other instruction will enter the pipeline except the one that follows the ATOMIC instruction and no interrupt request will be serviced in between All instructions requiring multiple cycles or hold states ar
346. rupt 4 Control Register 0000 CC13IC b FF92 C9 External Interrupt 5 Control Register 0000 CC14IC b FF94 CA External Interrupt 6 Control Register 0000 CC15lIC b FF96 CB External Interrupt 7 Control Register 0000 CP FE10 08 CPU Context Pointer Register FC00 CRIC b FF6A B5 GPT2 CAPREL Interrupt Control Register 0000 CSP FE08 04 CPU Code Segment Pointer Register 0000 8 bits not directly writeable Semiconductor Group 21 4 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value DPOL b F100 E 80 POL Direction Control Register 00 DPOH b F102 E 81 POH Direction Control Register 00 DP1L b F104 E82 P1L Direction Control Register 00 DP1H b F106 E 83 P1H Direction Control Register 00 DP2 b FFC2 E1 Port 2 Direction Control Register 0000 DP3 b FFC6 E3 Port 3 Direction Control Register 0000 DP4 b FFCA E5 Port 4 Direction Control Register 00 DP6 b FFCE E7 Port 6 Direction Control Register 00 DPPO FEOO 00 CPU Data Page Pointer 0 Register 10 bits 0000 DPP1 FE02 01 CPU Data Page Pointer 1 Register 10 bits 0001 DPP2 FE04 02 CPU Data Page Pointer 2 Register 10 bits 0002 DPP3 FE06 03 CPU Data Page Pointer 3 Register 10 bits 00034 EXICON b F1C0 E EO External Interrupt Control Register 0000 ICADR
347. rupt Control Register 0000 XP1IC b F18E E C7 FC Protocol Interrupt Control Register 0000 XP2IC b F196 E CB X Peripheral 2 Interrupt Control Register 0000 SOTBIC b F19C E CE Serial Channel 0 Transmit Buffer Interrupt Control 0000 Register XP3IC b F19E E CF X Peripheral 3 Interrupt Control Register 0000 Semiconductor Group 21 9 1998 05 01 SIEMENS The Register Set C161RI Name Physical 8 Bit Description Reset Address Address Value EXICON b F1C0 E EO External Interrupt Control Register 0000 ODP2 b F1C2 EJ E1 Port 2 Open Drain Control Register 0000 PICON F1C4 E E2 Port Input Threshold Control Register 0000 ODP3 b F1C6 E E3 Port 3 Open Drain Control Register 0000 ODP6 b Fi1CE E E7 Port 6 Open Drain Control Register 00 SYSCON2 b F1DO E E8 CPU System Configuration Register 2 0000 SYSCON3 b F1D4 E EA CPU System Configuration Register 3 0000 ISNC b F1DE E EF Interrupt Subnode Control Register 0000 DPPO FEOO 00 CPU Data Page Pointer 0 Register 10 bits 0000 DPP1 FE02 01 CPU Data Page Pointer 1 Register 10 bits 0001 DPP2 FE04 02 CPU Data Page Pointer 2 Register 10 bits 0002 DPP3 FE06 03 CPU Data Page Pointer 3 Register 10 bits 0003 CSP FE08 04 CPU Code Segment Pointer Register 0000 8 bits not directly writeable MDH FEOC 06 CPU Multiply Divide Register High Word
348. s 1 15 MCT02063 Figure 9 7 Memory Cycle Time The external bus cycles of the C161RI can be extended for a memory or peripheral which cannot keep pace with the controllers maximum speed by introducing wait states during the access see figure above During these memory cycle time wait states the CPU is idle if this access is required for the execution of the current instruction The memory cycle time wait states can be programmed in increments of one CPU clock 2 TCL within a range from O to 15 default after reset via the MCTC fields of the BUSCON registers 15 lt MCTC gt waitstates will be inserted Semiconductor Group 9 12 1998 06 01 SIEMENS The External Bus Interface C161RI Programmable Memory Tri State Time The C161RI allows the user to adjust the time between two subsequent external accesses to account for the tri state time of the external device The tri state time defines when the external device has released the bus after deactivation of the read command RD ja Bus Cycle Segment X Address X MTTC Wait State MCT02065 Figure 9 8 Memory Tri State Time The output of the next address on the external bus can be delayed for a memory or peripheral which needs more time to switch off its bus drivers by introducing a wait state after the previous bus cycle see figure above During this memory tri state time wait state the CPU is not idle
349. s Arithmetic and Logic Unit PSC es oer ese Asynchronous synchronous Serial Controller CISC cope Complex Instruction Set Computing CMOS nius Complementary Metal Oxide Silicon OPE e sau Less Central Processing Unit BBG esie External Bus Controller ESEH ues Extended Special Function Register Flash Non volatile memory that may be electrically erased GPR iex General Purpose Register GPT S suae stas General Purpose Timer unit HL utes High Level Language Pest eos Inter Integrated Circuit Bus I xk analat Input Output OTP 4 dans One Time Programmable memory PEG isgeria esn Peripheral Event Controller PEARL sero Programmable Logic Array PEE zio xs Phase Locked Loop PAIS e dt des Pulse Width Modulation BAM iioi Random Access Memory HIS vaste 4 46 Reduced Instruction Set Computing RON mes Read Only Memory SDD dies Slow Down Divider SRA obses Special Function Register oio PO PEE YE Synchronous Serial Controller ABU Siig vari Internal representation of the External Bus Semiconductor Group 1 7 1998 05 01 SIEMENS Architectural Overview C161RI 2 Architectural Overview The architecture of the C161RI combines the advantages of both RISC and CISC processors in a very well balanced way The sum of the features which are combined result in a high performance microcontroller which is the right choice not only for today s applications but also for future engineering challenges The C161RI not only integrates a powerf
350. s Interrupt Control SYSCON o_o E ICCFG T C Configuration Register ICADR I C Address Register ICCON T C Control Register XPOIC T C Data Interrupt Control Register ICST T C Status Register XP11C T C Protocol Interrupt Control Register Figure 17 1 SFRs Associated with the PC Bus Module The module can operate in three different modes e Master mode where the C161RI controls the bus transactions and provides the clock signal e Slave mode where an external master controls the bus transactions and provides the clock signal e Multimaster mode where several masters can be connected to the bus i e the C161RI can be master or slave The on chip I C bus module allows efficient communication over the common I C bus The module unloads the CPU of the C161RI of low level tasks like e De Serialization of bus data Generation of start and stop conditions e Monitoring the bus lines in slave mode e Evaluation of the device address in slave mode Bus access arbitration in multimaster mode Semiconductor Group 17 1 1998 05 01 SIEMENS The I2C Bus Module C161RI 17 4 PC Bus Conditions Data is transferred over the 2 line C bus SDA SCL using a protocol that ensures reliable and efficient transfers This protocol clearly distinguishes regular data transfers from defined control signals which control the data transfers The following bus conditions are defined Bus Idle SDA and SCL remain high The I C bus is c
351. s depends on the operating mode The SSC will automatically use the correct alternate input or output line of the ports when switching modes The direction of the pins however must be programmed by the user as shown in the tables Using the open drain output feature helps to avoid bus contention problems and reduces the need for hardwired hand shaking or slave select lines In this case it is not always necessary to switch the direction of a port pin The table below summarizes the required values for the different modes and pins SSC Port Control Pin Master Mode Slave Mode Function Port Latch Direction Function Port Latch Direction SCLK Serial Clock P3 132 1 DP3 132 1 Serial Clock P3 13 x DP3 13 0 Output Input MTSR Serial Data P3 9 T DP3 9 1 Serial Data P3 9 X DP3 9 0 Output Input MRST Serial Data P3 82 X DP3 8 2 0 SerialData P3 82 f DP3 8 2 1 Input Output Note In the table above an x means that the actual value is irrelevant in the respective mode however it is recommended to set these bits to 1 so they are already in the correct state when switching between master and slave mode 12 3 Baud Rate Generation The serial channel SSC has its own dedicated 16 bit baud rate generator with 16 bit reload capability allowing baud rate generation independent from the timers The baud rate generator is clocked with the CPU clock divided by 2 fcp 2
352. s in the figure above Semiconductor Group 9 16 1998 06 01 SIEMENS The External Bus Interface C161RI 9 4 Controlling the External Bus Controller A set of registers controls the functions of the EBC General features like the usage of interface pins WR BHE segmentation and internal ROM mapping are controlled via register SYSCON The properties of a bus cycle like chip select mode length of ALE external bus mode read write delay and waitstates are controlled via registers BUSCONA BUSCONO Four of these registers BUSCON4 BUSCON1 have an address select register ADDRSEL4 ADDRSEL1 associated with them which allows to specify up to four address areas and the individual bus characteristics within these areas All accesses that are not covered by these four areas are then controlled via BUSCONO This allows to use memory components or peripherals with different interfaces within the same system while optimizing accesses to each of them SYSCON FF12 89 SFR Reset Value 0XX0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 T BYT CLK WR CS BD VISI XPER rw w w WwW w w w mw w w w mw Bit Function XPER SHARE XBUS Peripheral Share Mode Control 0 External accesses to XBUS peripherals are disabled 1 XBUS peripherals are accessible via the external bus during hold mode VISIBLE Visible Mode Control 0 Accesses to XBUS peripherals are done internally 1 XBUS peripheral accesses are made visible on the e
353. s no possibility to program any port latches before Thus the alternate function CS is selected automatically in this case Note The open drain output option can only be selected via software earliest during the initialization routine the configured chip select lines via CSSEL will be in push pull output driver mode directly after reset Write ODP6 y Open Drain Latch Read ODP6 y Write DP6 y I p gt n t e r ira Alternate Function Enable B u S Write P6 y Alternate P6 y Output Buffer Clock MCB03904 Open drain output drivers on pins P6 5 P6 7 Figure 7 18 Block Diagram of Port 6 Pins with an Alternate Output Function Semiconductor Group 7 28 1998 05 01 Dedicated Pins C161RI SIEMENS 8 Dedicated Pins Most of the input output or control signals of the functional the C161RI are realized as alternate functions of pins of the parallel ports There is however a number of signals that use separate pins including the oscillator special control signals and of course the power supply The table below summarizes the 21 dedicated pins of the C161Hl Pin s Function ALE Address Latch Enable RD External Read Strobe WR WRL External Write Write Low Strobe HEADY Ready Input EA External Access Enable NMI Non Maskable Interrupt Input XTAL1 XTAL2 Oscillator Input Output R
354. s programmed via the upper two bits of register ADCON Bitfield ADCTC conversion time control selects the basic conversion clock used for the operation of the A D converter The sample time is derived from this conversion clock The table below lists the possible combinations The timings refer to CPU clock cycles where tepu 1 fopy The limit values for fa see data sheet must not be exceeded when selecting ADCTC and fopy ADCON 15 14 A D Converter Basic Clock Sample Time s Conversion Time f ADCTC fec 00 Jopu 2 feng X 12 tcpu X 62 01 Sepu 4 topu X 24 topu X 122 10 Sepu 8 topu X 48 topu X 242 11 fcpu 16 topy X 96 topy X 482 The time for a complete conversion includes the sample time 6 tgc the conversion itself and the time required to transfer the digital value to the result register 2 t py as shown in the example below Semiconductor Group 16 5 1998 05 01 SIEMENS The Analog Digital Converter C161RI Converter Timing Example Assumptions fcpy 16 MHz i e t py 62 5 ns ADCTC 01 Basic clock fac fepu 4 4 MHZ i e tg 250 ns Sample time ts fgoc x62 1500 ns Conversion time te 30 fgc 2 tcpy 7500 125 ns 7 625 us Note For the exact specification please refer to the data sheet of the selected derivative 16 3 A D Converter Interrupt Control At the end of each conversion interrupt request flag ADCIR in interrupt control register A
355. s received bytes ICRTB EDO8 XReg Reset Value XX 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 rw Bit Function ICData Transmit and shift data This field accepts the byte to be transmitted or provides the received byte Note A data transfer event interrupt request IRQD is cleared automatically when reading from or writing to ICRTB if bit AIRDIS 0 If AIRDIS 1 the request flag IRQD must be cleared via software Note It is recommended not to access the receive transmit buffer while a data transfer is in progress Semiconductor Group 17 11 1998 05 01 SIEMENS The I2C Bus Module C161RI 17 4 FC Interrupt Control The bit addressable interrupt control registers XPOIC and XP1IC are assigned to the IPC module The occurrence of an interrupt request sets the respective interrupt request bit XPOIR XP1IR If this interrupt node is enabled XPxEN 1 a CPU interrupt is generated and arbitrated These interrupt requests may be serviced via a standard service routine or with PEC transfers see below If polling of bits XPOIR and XP1IR is used please note that these request bits must be cleared via software Data transfer event interrupts are indicated by bit IRQD and allocated to vector XPOINT A data transfer event occurs after the acknowledge bit for a byte has been received or transmitted Protocol transfer event interrupts are indicated by bit IRQP and allocated to vector XP1INT A protocol transfer event
356. s serviced with the instruction SRVWDT which is a protected 32 bit instruction Servicing the watchdog timer clears the low byte and reloads the high byte of the watchdog timer register WDT with the preset value from bitfield WDTREL which is the high byte of register WDTCON Servicing the watchdog timer will also reset bit WDTR After being serviced the watchdog timer continues counting up from the value lt WDTREL gt x 25 Instruction SRVWDT has been encoded in such a way that the chance of unintentionally servicing the watchdog timer e g by fetching and executing a bit pattern from a wrong location is minimized When instruction SRVWDT does not match the format for protected instructions the Protection Fault Trap will be entered rather than the instruction be executed The time period for an overflow of the watchdog timer is programmable in two ways theinput frequency to the watchdog timer can be selected via bit WDTIN in register WDTCON to be either fopu 2 or f 128 the reload value WDTREL for the high byte of WDT can be programmed in register WDTCON The period Pyp between servicing the watchdog timer and the next overflow can therefore be determined by the following formula D 1 lt WDTIN gt x6 yc 275 WDTREL x 2 fou Pwor z The table below marks the possible ranges for the watchdog time which can be achieved using a certain CPU clock Some numbers are rounded to 3 significant digits Watchdog Time Ranges
357. scillator frequency of 20 MHz Semiconductor Group 14 2 1998 06 01 SIEMENS The Real Time Clock C161RI RTC Register Access The actual value of the RTC is represented by the 3 registers T14 RTCL and RTCH As these registers are concatenated to build the RTC counter chain internal overflows occur while the RTC is running When reading or writing the RTC value make sure to account for such internal overflows in order to avoid reading writing corrupted values When reading writing e g 0000 to RTCH and then accessing RTCL will produce a corrupted value as RTCL may overflow before it can be accessed In this case however RTCH would be 0001 The same precautions must be taken for T14 and T14REL 14 1 RTC Interrupt Generation The RTC interrupt shares the XPERS3 interrupt node with the PLL OWD interrupt if available This is controlled by the interrupt subnode control register ISNC The interrupt handler can determine the source of an interrupt request via the separate interrupt request and enable flags see figure below provided in register ISNC Note If only one source is enabled no additional software check is required of course Intr Request Intr Enable XPER3 Interrupt Interrupt Node Controller T14 Interrupt Intr Request Intr Enable i Register ISNC Register XP3IC Note Only available if PLL is implemented Figure 14 3 RTC Interrupt Logic If T14 interrupts are to be used both stages
358. se all 16 bits of the operand address are used as segment offset with the segment taken from the EXTS instruction This greatly simplifies address calculation with continuous data like huge arrays in C EXTS 15 1 The override seg is 15 0F 0000H 0F FFFFH MOV RO R14 The 16 bit segment offset is stored in R14 MOV R1 R13 This instruction uses the std DPP scheme Note Instructions EXTP and EXTS inhibit interrupts the same way as ATOMIC Short Addressing in the Extended SFR ESFR Space The short addressing modes of the C161RI REG or BITOFF implicitly access the SFR space The additional ESFR space would have to be accessed via long addressing modes MEM or Rw The EXTR extend register instruction redirects accesses in short addressing modes to the ESFR space for 1 4 instructions so the additional registers can be accessed this way too The EXTPR and EXTSR instructions combine the DPP override mechanism with the redirection to the ESFR space using a single instruction Note Instructions EXTR EXTPR and EXTSR inhibit interrupts the same way as ATOMIC The switching to the ESFR area and data page overriding is checked by the development tools or handled automatically Nested Locked Sequences Each of the described extension instruction and the ATOMIC instruction starts an internal extension counter counting the effected instructions When another extension or ATOMIC instruction is contained in the current locke
359. signals from the instruction decode logic These are summarized below and described in detail in the following sections 1 High Instruction Bandwidth Fast Execution 2 High Function 8 bit and 16 bit Arithmetic and Logic Unit 3 Extended Bit Processing and Peripheral Control 4 High Performance Branch Call and Loop Processing 5 Consistent and Optimized Instruction Formats 6 Programmable Multiple Priority Interrupt Structure Semiconductor Group 2 2 1998 05 01 SIEMENS Architectural Overview C161RI High Instruction Bandwidth Fast Execution Based on the hardware provisions most of the C161RI s instructions can be executed in just one machine cycle which requires 2 CPU clock cycles 2 x 1 fopy 4 TCL For example shift and rotate instructions are always processed within one machine cycle independent of the number of bits to be shifted Branch multiply and divide instructions normally take more than one machine cycle These instructions however have also been optimized For example branch instructions only require an additional machine cycle when a branch is taken and most branches taken in loops require no additional machine cycles at all due to the so called Jump Cache A 32 bit 16 bit division takes 20 CPU clock cycles a 16 bit x 16 bit multiplication takes 10 CPU clock cycles The instruction cycle time has been dramatically reduced through the use of instruction pipelining This techniqu
360. sions like system maintenance firmware update or end of line programming or testing Semiconductor Group 15 1 1998 05 01 SIEMENS The Bootstrap Loader C161RI Entering the Bootstrap Loader The C161HRI enters BSL mode if pin POL 4 is sampled low at the end of a hardware reset In this case the built in bootstrap loader is activated independent of the selected bus mode The bootstrap loader code is stored in a special Boot ROM no part of the standard mask ROM OTP or Flash memory area is required for this After entering BSL mode and the respective initialization the C161RI scans the RXDO line to receive a zero byte i e one start bit eight 0 data bits and one stop bit From the duration of this zero byte it calculates the corresponding baudrate factor with respect to the current CPU clock initializes the serial interface ASCO accordingly and switches pin TxDO to output Using this baudrate an identification byte is returned to the host that provides the loaded data This identification byte identifies the device to be bootet The following codes are defined 554 8xC166 A5 Previous versions of the C167 obsolete B5 C165 C5 C167 derivatives D5 All devices equipped with identification registers Note The identification byte D5 does not directly identify a specific derivative This information can in this case be obtained from the identification registers When the C161RI has entered BSL mode the following co
361. so CPU operations will only be slowed down if a subsequent external instruction or data fetch operation is required during the next instruction cycle The memory tri state time waitstate requires one CPU clock 2 TCL and is controlled via the MTTCx bits of the BUSCON registers A waitstate will be inserted if bit MTTCx is 0 default after reset Note External bus cycles in multiplexed bus modes implicitly add one tri state time waitstate in addition to the programmable MTTC waitstate Semiconductor Group 9 13 1998 06 01 SIEMENS The External Bus Interface C161RI Read Write Signal Delay The C161RI allows the user to adjust the timing of the read and write commands to account for timing requirements of external peripherals The read write delay controls the time between the falling edge of ALE and the falling edge of the command Without read write delay the falling edges of ALE and command s are coincident except for propagation delays With the delay enabled the command s become active half a CPU clock 1 TCL after the falling edge of ALE The read write delay does not extend the memory cycle time and does not slow down the controller in general In multiplexed bus modes however the data drivers of an external device may conflict with the C161RI s address when the early RD signal is used Therefore multiplexed bus cycles should always be programmed with read write delay a Bus Cycle Segment Address ALE
362. stem Reset C161RI Hardware Reset A hardware reset is triggered when the reset input signal RSTIN is latched low To ensure the recognition of the RSTIN signal latching it must be held low for at least 2 CPU clock cycles Also shorter RSTIN pulses may trigger a hardware reset if they coincide with the latch s sample point However it is recommended to keep RSTIN low for ca 1 ms After the reset sequence has been completed the RSTIN input is sampled When the reset input signal is active at that time the internal reset condition is prolonged until RSTIN gets inactive During a hardware reset the PORTO inputs for the reset configuration need some time to settle on the required levels especially if the hardware reset aborts a read operation from an external peripheral During this settling time the configuration may intermittently be wrong The input RSTIN provides an internal pullup device equalling a resistor of 50 KO to 150 KO the minimum reset time must be determined by the lowest value Simply connecting an external capacitor is sufficient for an automatic power on reset see b in figure above RSTIN may also be connected to the output of other logic gates see a in figure above See also section Bidirectional Reset in this case Note A power on reset requires an active time of two reset sequences 1036 CPU clock cycles after a stable clock signal is available about 10 50 ms to allow the on chip oscillator to stabiliz
363. ster 7 bits 00 P5 b FFA2 Dih Port 5 Register read only XXXXy P5DIDIS b FFA4 D24 Port 5 Digital Input Disable Register 00004 P6 b FFCC E64 Port 6 Register 8 bits 00 PECCO FECO 60 PEC Channel 0 Control Register 0000 PECC1 FEC2 61 PEC Channel 1 Control Register 0000 PECC2 FECA 62 PEC Channel 2 Control Register 0000 PECC3 FEC6 63 PEC Channel 3 Control Register 0000 PECC4 FEC8 64 PEC Channel 4 Control Register 0000 PECC5 FECA 165 PEC Channel 5 Control Register 0000 PECC6 FECC 166 PEC Channel 6 Control Register 0000 PECC7 FECE 67 PEC Channel 7 Control Register 0000 PICON F1C4 E E2 Port Input Threshold Control Register 0000 PSW b FF10 88 CPU Program Status Word 0000 RPOH b F108 E 84 System Startup Configuration Register Rd only XX RTCH FOD6 E 6B RTC High Register no RTCL FOD4 E 6A RTC Low Register no SOBG FEB4 5A Serial Channel 0 Baud Rate Generator Reload 0000 Register SOCON b FFBO D8 Serial Channel 0 Control Register 0000 SOEIC b FF70 B8 Serial Channel 0 Error Interrupt Control Register 0000 SORBUF FEB2 59 Serial Channel 0 Receive Buffer Register XXXX read only SORIC b FF6E B7 Serial Channel 0 Receive Interrupt Control 0000 Register SOTBIC b F19C E CE Serial Channel 0 Transmit Buffer Interrupt Control 0000 Register SOTBUF FEBO 58 Serial Channel 0 Transmit Buffer Register 0000 SOTIC b FF6C B6 Serial Channel 0 Transmit Interrupt Control 0000 R
364. ster Receive Slave Transmit P3 9 MTSR SSC Master Transmit Slave Receive P3 10 TxDO ASCO Transmit Data Output P3 11 RxDO ASCO Receive Data Input P3 12 BHE WRH Byte High Enable Write High Output P3 13 SCLK SSC Shift Clock Input Output P3 15 CLKOUT System Clock Output Alternate Function b CLKOUT SCLK BHE RxDO TxDO MTSR MRST T2IN TSIN TAIN T3EUD TSOUT CAPIN SDAO SCLO General Purpose Input Output Figure 7 10 Port 3 IO and Alternate Functions Semiconductor Group 7 16 1998 05 01 SIEMENS Parallel Ports C161RI The port structure of the Port 3 pins depends on their alternate function see figure below When the on chip peripheral associated with a Port 3 pin is configured to use the alternate input function it reads the input latch which represents the state of the pin via the line labeled Alternate Data Input Port 3 pins with alternate input functions are T2IN TSIN T4IN T3EUD and CAPIN When the on chip peripheral associated with a Port 3 pin is configured to use the alternate output function its Alternate Data Output line is ANDed with the port output latch line When using these alternate functions the user must set the direction of the port line to output DP3 y 1 and must set the port output latch P3 y 1 Otherwise the pin is in its high impedance state when configured as input or the pin is stuck at 0 when the port output latch is cleared When the al
365. struction must not immediately follow an instruction updating the SP register SP FE12 09 SFR Reset Value FC00 15 44 11 10 9 8 7 6 5 4 3 2 1 0 13 12 cbbb l uut s s e r r r r rw r Bit Function sp Modifiable portion of register SP Specifies the top of the internal system stack Semiconductor Group 4 24 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Stack Overflow Pointer STKOV This non bit addressable register is compared against the SP register after each operation which pushes data onto the system stack e g PUSH and CALL instructions or interrupts and after each subtraction from the SP register If the content of the SP register is less than the content of the STKOV register a stack overflow hardware trap will occur Since the least significant bit of register STKOV is tied to 0 and bits 15 through 12 are tied to 1 by hardware the STKOV register can only contain values from F000 to FFFE STKOV FE14 0A SFR Reset Value FA00 15 14 11 10 9 8 7 6 5 4 3 2 1 0 13 12 a m s s lt r r r r rw r Bit Function stkov Modifiable portion of register STKOV Specifies the lower limit of the internal system stack The Stack Overflow Trap entered when SP STKOV may be used in two different ways Fatal error indication treats the stack overflow as a system error through the associated trap service routine Under these circumstances data in the bott
366. t CT3 selects the external input pin CAPIN or the input pins of timer T3 as the source for a capture trigger Either a positive a negative or both a positive and a negative transition at pin CAPIN can be selected to trigger the capture function or transitions on input T3IN or input T3EUD or both inputs T3IN and T3EUD The active edge is controlled by bit field Cl in register TSCON The maximum input frequency for the capture trigger signal at CAPIN is fGpy 4 To ensure that a transition of the capture trigger signal is correctly recognized its level should be held for at least 4 fopy cycles before it changes When the timer T3 capture trigger is enabled CT3 1 register CAPREL captures the contents of T5 upon transitions of the selected input s These values can be used to measure T3 s input signals This is useful e g when T3 operates in incremental interface mode in order to derive dynamic information speed acceleration from the input signals When a selected transition at the selected input pin s CAPIN T3IN T3EUD is detected the contents of the auxiliary timer T5 are latched into register CAPREL and interrupt request flag CRIR is set With the same event timer T5 can be cleared to 0000 This option is controlled by bit TBCLR in register T5CON If T5CLR 0 the contents of timer T5 are not affected by a capture If T5CLR 1 timer T5 is cleared after the current timer value has been latched into register CAPREL
367. t byte give ack ICCON amp ACKDIS acknowledge from master ICCON amp TRX TRX 0 for master receiver dummy ICRTB start clock to receive the 1st byte while ICST amp IRQD 0x0000 waiting for end of 1st byte read first byte drive clock for second give no ack ICCON ACKDIS no acknowledge from master array 0 ICRTB read ICRTB 1st byte start clock to receive the 2nd byte while ICST amp IRQD 20x0000 waiting for end of 2nd byte read 2nd byte without automatic clear of IRQD generate STOP ICCON AIRDIS AIRDIS 1 read ICRTB send no clock array 1 ICRTB read ICRTB 2nd byte ICCON amp BUM BUM 0 initiate stop condition ICST amp IRQD Clear bit IRQD Semiconductor Group 17 15 1998 05 01 SIEMENS System Reset C161RI 18 System Reset The internal system reset function provides initialization of the C161RI into a defined default state and is invoked either by asserting a hardware reset signal on pin RSTIN Hardware Reset Input upon the execution of the SRST instruction Software Reset or by an overflow of the watchdog timer Whenever one of these conditions occurs the microcontroller is reset into its predefined default state through an internal reset procedure When a reset is initiated pending internal hold states are cancelled and the current internal access cycle if any is completed An external bus cycle is aborted except for a watchdog reset
368. t cases takes only one machine cycle This performance is achieved by the following mechanism Whenever a cache jump instruction passes through the decode stage of the pipeline for the first time and provided that the jump condition is met the jump target instruction is fetched as usual causing a time delay of one machine cycle In contrast to standard branch instructions however the target instruction of a cache jump instruction JMPA JMPR JB JBC JNB JNBS is additionally stored in the cache after having been fetched After each repeatedly following execution of the same cache jump instruction the jump target instruction is not fetched from program memory but taken from the cache and immediately injected into the decode stage of the pipeline see figure below A time saving jump on cache is always taken after the second and any further occurrence of the same cache jump instruction unless an instruction which has the fundamental capability of changing the CSP register contents JMPS CALLS RETS TRAP RETI or any standard interrupt has been processed during the period of time between two following occurrences of the same cache jump instruction 5 RUM ad Injection In jection of cached Target Instruction lTaRGET 1 ltarcet 2 Cache Jmp Itarcet lrARGET 1 Cycle 1st loop iteration Repeated loop iteration gt Figure 4 4 Cache Jump Instruction Pipelinin
369. t field TxM in the respective register TXCON to 001 In counter mode timers T2 and T4 can be clocked either by a transition at the respective external input pin TxIN or by a transition of timer T3 s output toggle latch T3OTL Edge Select TxIN eo Auxiliary Timer Tx TxIR Te i Request j Up TxR Txl Down TxUD ee a MUX Lp TEUD Ea EXOR 1 Truu x 2 4 MCB02221 Figure 10 10 Block Diagram of an Auxiliary Timer in Counter Mode The event causing an increment or decrement of a timer can be a positive a negative or both a positive and a negative transition at either the respective input pin or at the toggle latch T3OTL Bit field Txl in the respective control register TxCON selects the triggering transition see table below GPT1 Auxiliary Timer Counter Mode Input Edge Selection T21 TAI Triggering Edge for Counter Increment Decrement X00 None Counter Tx is disabled 001 Positive transition rising edge on TxIN 010 Negative transition falling edge on TxIN 0 1 1 Any transition rising or falling edge on TxIN 101 Positive transition rising edge of output toggle latch T3OTL 110 Negative transition falling edge of output toggle latch T3OTL 111 Any transition rising or falling edge of output toggle latch T3OTL Note Only state transitions of T3OTL which are caused by the overflows underflows of T3 will trigger the counter function of T2 T4 Modifications of T3OTL via so
370. t frequency may be switched to fopy 128 by setting bit WDTIN The watchdog timer can be disabled via the instruction DISWDT Disable Watchdog Timer Instruction DISWDT is a protected 32 bit instruction which will ONLY be executed during the time between a reset and execution of either the EINIT End of Initialization or the SRVWDT Service Watchdog Timer instruction Either one of these instructions disables the execution of DISWDT Note After a hardware reset that activates the Bootstrap Loader the watchdog timer will be disabled When the watchdog timer is not disabled via instruction DISWDT it will continue counting up even during Idle Mode If it is not serviced via the instruction SRVWDT by the time the count reaches FFFF the watchdog timer will overflow and cause an internal reset This reset will pull the external reset indication pin RSTOUT low and RSTIN in bidirectional reset mode The Watchdog Timer Reset Indication Flag WDTR in register WDTCON will be set in this case Semiconductor Group 13 2 1998 05 01 The Watchdog Timer WDT C161RI SIEMENS A watchdog reset will also complete a running external bus cycle before starting the internal reset sequence if this bus cycle does not use READY or samples READY active low after the programmed waitstates Otherwise the external bus cycle will be aborted To prevent the watchdog timer from overflowing it must be serviced periodically by the user software The watchdog timer i
371. t sequence which starts after synchronization of RSTIN A short hardware reset is extended until the end of the reset sequence in Bidirectional reset mode A software or WDT reset activates the RSTIN line in Bidirectional reset mode MCD03902 Figure 18 3 Reset Input and Output Signals Semiconductor Group 18 4 1998 06 01 SIEMENS System Reset C161RI Reset Output Pin The RSTOUT pin is dedicated to generate a reset signal for the system components besides the controller itself RSTOUT will be driven active low at the begin of any reset sequence triggered by hardware the SRST instruction or a watchdog timer overflow RSTOUT stays active low beyond the end of the internal reset sequence until the protected EINIT End of Initialization instruction is executed see figure above This allows the complete configuration of the controller including its on chip peripheral units before releasing the reset signal for the external peripherals of the system Note RSTOUT will float as long as pins POL O and POL 1 select emulation mode or adapt mode Watchdog Timer Operation after Reset The watchdog timer starts running after the internal reset has completed It will be clocked with the internal system clock divided by 2 fep 2 and its default reload value is 00 so a watchdog timer overflow will occur 131072 CPU clock cycles 2 25 after completion of the internal reset unless it is disabled serviced or reprogrammed me
372. tection Control Oriented Instruction Set with High Efficiency Bit byte and word data types Flexible and efficient addressing modes for high code density Enhanced boolean bit manipulation with direct addressability of 6 Kbits for peripheral control and user defined flags Hardware traps to identify exception conditions during runtime HLL support for semaphore operations and efficient data access Integrated On chip Memory 1 KByte internal RAM for variables register banks system stack and code 2 KByte on chip high speed XRAM for variables user stack and code External Bus Interface Multiplexed or demultiplexed bus configurations Segmentation capability and chip select signal generation 8 bit or 16 bit data bus Bus cycle characteristics selectable for five programmable address areas 16 Priority Level Interrupt System 27 interrupt nodes with separate interrupt vectors 300 500 ns typical maximum interrupt latency in case of internal program execution Fast external interrupts Semiconductor Group 1 4 1998 05 01 SIEMENS Introduction C161RI 8 Channel Peripheral Event Controller PEC Interrupt driven single cycle data transfer Transfer count option standard CPU interrupt after a programmable number of PEC transfers Eliminates overhead of saving and restoring system state for interrupt requests Intelligent On chip Peripheral Subsystems 4 Channel 8 bit A D Converter with programmab
373. ted when the incoming data at pin MRST master mode or MTSR slave mode sampled with the same frequency as the CPU clock changes between one sample before and two samples after the latching edge of the clock signal see Clock Control This condition sets the error flag SSCPE and when enabled via SSCPEN the error interrupt request flag SSCEIR A Baud Rate Error Slave mode is detected when the incoming clock signal deviates from the programmed baud rate by more than 100 i e it either is more than double or less than half the expected baud rate This condition sets the error flag SSCBE and when enabled via SSCBEN the error interrupt request flag SSCEIR Using this error detection capability requires that the slave s baud rate generator is programmed to the same baud rate as the master device This feature detects false additional or missing pulses on the clock line within a certain frame Note If this error condition occurs and bit SSCAREN 1 an automatic reset of the SSC will be performed in case of this error This is done to reinitialize the SSC if too few or too many clock pulses have been detected Semiconductor Group 12 12 1998 05 01 SIEM ENS The High Speed Synchronous Serial Interface C161RI A Transmit Error Slave mode is detected when a transfer was initiated by the master shift clock gets active but the transmit buffer SSCTB of the slave was not updated since the last transfer This condition sets the erro
374. ted in the internal RAM of the C161RI An area of 32 256 words or all of the internal RAM may be dedicated to the system stack A so called circular stack mechanism allows to use a bigger virtual stack than this dedicated RAM area These techniques as well as the encoding of bitfield STKSZ are described in more detail in chapter System Programming Semiconductor Group 4 13 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Processor Status Word PSW This bit addressable register reflects the current state of the microcontroller Two groups of bits represent the current ALU status and the current CPU interrupt status A separate bit USRO within register PSW is provided as a general purpose user flag PSW FF10 88 SFR Reset Value 0000 15 14 13 12 11 0 10 9 8 7 6 5 4 3 2 1 HLD MUL ILVL EN IP V C rw rw w mw w w mw rw rw ed Bit Function N Negative Result Set when the result of an ALU operation is negative C Carry Flag Set when the result of an ALU operation produces a carry bit V Overflow Result Set when the result of an ALU operation produces an overflow Z Zero Flag Set when the result of an ALU operation is zero E End of Table Flag Set when the source operand of an instruction is 8000 or 80 MULIP Multiplication Division In Progress 0 There is no multiplication division in progress 1 A multiplication division has been interrupted
375. ter Updating An instruction which calculates a physical operand address via a particular DPPn n 0 to 3 register is mostly not capable of using a new DPPn register value which is to be updated by an immediately preceding instruction Thus to make sure that the new DPPn register value is used at least one instruction must be inserted between a DPPn changing instruction and a subsequent instruction which implicitly uses DPPn via a long or indirect addressing mode as shown in the following example I MOV DPPO 4 select data page 4 via DPPO lus Nes must not be an instruction using DPPO MOV DPP0 0000H R1 move contents of R1 to address location 01 0000 in data page 4 supposed segmentation is enabled e Explicit Stack Pointer Updating None of the RET RETI RETS RETP or POP instructions is capable of correctly using a new SP register value which is to be updated by an immediately preceding instruction Thus in order to use the new SP register value without erroneously performed stack accesses at least one instruction must be inserted between an explicitly SP writing and any subsequent of the just mentioned implicitly SP using instructions as shown in the following example la MOV SP 0FA40H Select a new top of stack lia bats must not be an instruction popping operands from the system stack Inge POP RO pop word value from new top of stack into RO Note Conflicts with instructions writing to the stac
376. ter access Systems that utilize several FC channels can prepare a set of control words which configure the respective channels By writing one of these control words to ICCFG the respective channel is selected Different channels may use different baudrates Also different operating modes can be selected e g enabling all physical interfaces for a broadcast transmission Note See also section The Physical I C Bus Interface ICCFG EDO00 XReg Reset Value XX00 15 14 13 12 11 10 9 8 0 7 6 5 4 3 2 1 BRP SCL SCL SDA SDA SDA SEL1 SELO SEL2 SEL1 SELO rw rw rw rw rw rw Bit Function SDASELx SDA Pin Selection These bits determine to which pins the I C data line is connected 0 SDA pin xis disconnected 1 SDApinxis connected with FC data line SCLSELx SCL Pin Selection These bits determine to which pins the I C clock line is connected 0 SCL pin x is disconnected 1 SCL pin x is connected with FC clock line BRP Baudrate Prescaler Determines the baudrate for the active IC channel s The resulting baudrate is Bic fcpu 4 x BRP 1 See table below PC Bus Baudrate Selection CPU Frequency fcpy Reload Value for BRP 100 KBd 400 KBd 20 MHz 31 OB or 0C 16 MHz 27 09 12 MHz 1D 06 or 07 10 MHz 18 05 1 MHz 01 or 02 Not possible Semiconductor Group 17 8 1998 05 01 2 SIEMENS The I2C Bus Module C161RI ICCON ED02 XReg Reset V
377. ternate data can be the 16 bit intrasegment address or the 8 16 bit data information The incoming data on PORTO is read on the line Alternate Data Input While an external bus mode is enabled the user software should not write to the port output latch otherwise unpredictable results may occur When the external bus modes are disabled the contents of the direction register last written by the user becomes active The figure below shows the structure of a PORTO pin Write DPOH y DPOL y Alternate Direction Direction Latch M Read DPOH y DPOL y I Alternate n Function P Enable r n Write POH y POL y Alternate a Data 1 Output id Port Output Output U S Read POH y POL y Clock p Y Input Latch MCB02231 y 7 0 Figure 7 5 Block Diagram of a PORTO Pin Semiconductor Group 7 8 1998 05 01 SIEMENS Parallel Ports C161RI 7 2 PORTI The two 8 bit ports P1H and P1L represent the higher and lower part of PORT1 respectively Both halfs of PORT1 can be written e g via a PEC transfer without effecting the other half If this port is used for general purpose IO the direction of each line can be configured via the corresponding direction registers DP1H and DP1L P1L FF04 82 SFR Reset Value 00 15 14 13 12 11 10 9 8 bin aa 6 5 4 3 2 1 0 P1L 7 P1L 6 P1L 5 P1L A P1L 3 P1L 2 P1L 1 P1L O P1H FF06 83 SFR Reset Value 00 8 7 6 5 4 3 2 1 0
378. ternate output functions are not used the Alternate Data Output line is in its inactive state which is a high level 1 Port 3 pins with alternate output functions are T3OUT TxDO and CLKOUT When the on chip peripheral associated with a Port 3 pin is configured to use both the alternate input and output function the descriptions above apply to the respective current operating mode The direction must be set accordingly Port 3 pins with alternate input output functions are SCLO SDAO MTSR MRST RxDO and SCLK Note Enabling the CLKOUT function automatically enables the P3 15 output driver Setting bit DP3 15 1 is not required The CLKOUT function is automatically enabled in emulation mode Pins P3 0 and P3 1 provide open drain output drivers only in order to be compatible with the FC Bus specification Semiconductor Group 7 17 1998 05 01 SIEMENS Parallel Ports C161RI ZX Write ODP3 y Open Drain Latch Read ODP3 y I n t Direction e Latch r n Read DP3 y a Alternate Data E Output u 5 Write P3 y Port Output P3 y Buffer Read P3 y Clock 1 la MUX i Input Latch SZ pis MCB02229 y 13 11 0 Input Open drain output drivers on pins P3 0 and P3 1 Figure 7 11 Block Diagram of a Port 3 Pin with Alternate Input or Alternate Output Function Semiconductor Group 7 18 1998 05 01 SIEMENS Parallel Ports C161RI Pin P3 12 BHE WRH is
379. ters but directly access the registers within this 512 Byte area short 8 bit reg addresses to the extended ESFR area require switching to the 512 Byte extended SFR area This is done via the EXTension instructions EXTR EXTP R EXTS R Byte write operations to word wide SFRs via indirect or direct 16 bit mem addressing or byte transfers via the PEC force zeros in the non addressed byte Byte write operations via short 8 bit reg addressing can only access the low byte of an SFR and force zeros in the high byte It is therefore recommended to use the bit field instructions BFLDL and BFLDH to write to any number of bits in either byte of an SFR without disturbing the non addressed byte and the unselected bits Reserved Bits Some of the bits which are contained in the C161RI s SFRs are marked as Reserved User software should never write 1 s to reserved bits These bits are currently not implemented and may be used in future products to invoke new functions In this case the active state for these functions will be 1 and the inactive state will be 0 Therefore writing only 0 s to reserved locations provides portability of the current software to future devices After read accesses reserved bits should be ignored or masked out Parallel Ports The C161RI provides up to 76 IO lines which are organized into six input output ports and one input port All port lines are bit addressable and all input output lines are individually
380. the CPU clock the reload value the value of SOBRS and the operating mode asynchronous or synchronous Register SOBG is the dual function Baud Rate Generator Reload register Reading SOBG returns the content of the timer bits 15 13 return zero while writing to SOBG always updates the reload register bits 15 13 are insignificant An auto reload of the timer with the content of the reload register is performed each time SOBG is written to However if SOR 0 at the time the write operation to SOBG is performed the timer will not be reloaded until the first instruction cycle after SOR 1 Semiconductor Group 11 10 1998 05 01 The Asynchronous Synchronous Serial Interface C161RI SIEMENS Asynchronous Mode Baud Rates For asynchronous operation the baud rate generator provides a clock with 16 times the rate of the established baud rate Every received bit is sampled at the 7th 8th and 9th cycle of this clock The baud rate for asynchronous operation of serial channel ASCO and the required reload value for a given baudrate can be determined by the following formulas Jeru foru Basne So S0BRL 1 Asyne 16 x 2 lt SOBRS gt x lt SOBRL gt 1 16 x 2 SOBRS X Bas lt SOBRL gt represents the content of the reload register taken as unsigned 13 bit integer lt SOBRS gt represents the value of bit SOBRS i e 0 or 1 taken as integer The maximum baud rate that can be achieved f
381. the byte accessible registers receive special names Name Physical 8 Bit Description Reset Address Address Value RLO CP 0 F0 CPU General Purpose Byte Register RLO UU RHO CP 1 F1 CPU General Purpose Byte Register RHO UU RL1 CP 2 F24 CPU General Purpose Byte Register RL1 UU RH1 CP 3 F3 CPU General Purpose Byte Register RH1 UU RL2 CP 4 FA CPU General Purpose Byte Register RL2 UU RH2 CP 4 5 F5 CPU General Purpose Byte Register RH2 UU RL3 CP 6 F6 CPU General Purpose Byte Register RL3 UU RH3 CP 7 F7 CPU General Purpose Byte Register RH3 UU RL4 CP 8 F8 CPU General Purpose Byte Register RL4 UU RH4 CP 9 F9 CPU General Purpose Byte Register RH4 UU RL5 CP 10 FA CPU General Purpose Byte Register RL5 UU RH5 CP 11 FBj CPU General Purpose Byte Register RH5 UU RL6 CP 12 FC CPU General Purpose Byte Register RL6 UU RH6 CP 13 FD CPU General Purpose Byte Register RH6 UU RL7 CP 14 FE CPU General Purpose Byte Register RL7 UU RH7 CP 14 FF CPU General Purpose Byte Register RH7 UU Semiconductor Group 21 3 1998 05 01 SIEMENS The Register Set C161RI 21 3 Special Function Registers ordered by Name The following table lists all SFRs which are implemented in the C161RI in alphabetical order Bit addressable SFRs are marked with the letter b in column Name SFRs within the
382. the corresponding multiply or divide operation Register MDC is updated by hardware during each single cycle of a multiply or divide instruction MDC FFOE 87 SFR Reset Value 0000 15 1 4 13 12 1 10 9 8 7 6 5 4 3 2 1 i mw rw rw rw rw rw rw 0 r w Bit Function MDRIU Multiply Divide Register In Use 0 Cleared when register MDL is read via software 1 Set when register MDL or MDH is written via software or when a multiply or divide instruction is executed i Internal Machine Status The multiply divide unit uses these bits to control internal operations Never modify these bits without saving and restoring register MDC When a division or multiplication was interrupted before its completion and the multiply divide unit is required the MDC register must first be saved along with registers MDH and MDL to be able to restart the interrupted operation later and then it must be cleared prepare it for the new calculation After completion of the new division or multiplication the state of the interrupted multiply or divide operation must be restored The MDRIU flag is the only portion of the MDC register which might be of interest for the user The remaining portions of the MDC register are reserved for dedicated use by the hardware and should never be modified by the user in another way than described above Otherwise a correct continuation of an interrupted multiply or divide opera
383. this combination Semiconductor Group 10 8 1998 05 01 The General Purpose Timer Units C161RI SIEMENS The incremental encoder can be connected directly to the C161RI without external interface logic In a standard system however comparators will be employed to convert the encoder s differential outputs e g A A to digital signals e g A This greatly increases noise immunity Note The third encoder output TopO which indicates the mechanical zero position may be connected to an external interrupt input and trigger a reset of timer T3 e g via PEC transfer from ZEROS T3input T3input 1 o o o c Lu Interrupt conditioning Figure 10 7 Connection of the Encoder to the C161RI For incremental interface operation the following conditions must be met e Bitfield T3M must be 110 Both pins T3IN and T3EUD must be configured as input i e the respective direction control bits must be 0 e Bt be 1 to enable automatic direction control The maximum input frequency which is allowed in incremental interface mode is fgpy 16 To ensure that a transition of any input signal is correctly recognized its level should be held high or low for at least 8 fopy cycles before it changes In Incremental Interface Mode the count direction is automatically derived from the sequence in which the input signals change which corresponds to the rotation direction of the connected sensor The
384. tion ICCON 0x0008 ICST 0x0000 ICCFG 0x2711 XPOIC 0x0000 XP1IC 0x0000 P3 _bfld_ P3 0x0003 0x0003 bfld DP3 0x0003 0x0003 slave address ICRTB 0x0000 OxAO0 ICCON BUM while ICST amp IRQD 0x0000 if ICST amp LRB ICST amp AL ICST amp IRQP sub address ICRTB 0x0000 0x0000 while ICST amp IRQD 0x0000 if ICST amp LRB ICST amp AL ICST amp IROP switch to master receiver ICCON RSC ICRTB 0x0000 0xA1 while ICST amp IRQD 0x0000 if ICST amp LRB master mode reset status register 100kHz 16MHz SDAO SCLO disable interrupt IRQD use polling disable interrupt IROP use polling configuration provide external pullups on I2C lines enable alternate function on P3 0 1 switch i2c pins to output write transmit buffer BUM 1 start cond send slave addr waiting for end of transmission ACK Clear bit AL Clear bit IRQP send sub address waiting for end of transmission ACK Clear bit AL Clear bit IRQP send slave address with a repeated start repeated start condition write to transmit buffer waiting for end of transmission ACK ICST amp AL Clear bit AL ICST amp IRQP Clear bit IRQP Semiconductor Group 17 14 1998 05 01 2 SIEMENS The I2C Bus Module C161RI drive clock SCL for firs
385. tion cannot be guaranteed A detailed description of how to use the MDC register for programming multiply and divide algorithms can be found in chapter System Programming Semiconductor Group 4 28 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI The Constant Zeros Register ZEROS All bits of this bit addressable register are fixed to 0 by hardware This register can be read only Register ZEROS can be used as a register addressable constant of all zeros i e for bit manipulation or mask generation It can be accessed via any instruction which is capable of addressing an SFR ZEROS FF1C 8E SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 The Constant Ones Register ONES All bits of this bit addressable register are fixed to 1 by hardware This register can be read only Register ONES can be used as a register addressable constant of all ones i e for bit manipulation or mask generation It can be accessed via any instruction which is capable of addressing an SFR ONES FF1E 8F SFR Reset Value FFFF 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Semiconductor Group 4 29 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI 5 Interrupt and Trap Functions The architecture of the C161RI supports several mechanisms for fast and flexible response to service requests that can be generated from various sources internal or external to the microcontroller These mechanisms incl
386. tions SOBG SOCON SOTIC SOTBUF SORIC SORBUF SOEIC SOTBIG E RXDO P3 11 TXDO P3 10 ODP3 Port 3 Open Drain Control Register DP3 Port 3 Direction Control Register P3 Port 3 Data Register SOBG ASCO Baud Rate Generator Reload Register SOCON ASCO Control Register SOTBUF ASCO Transmit Buffer Register SORBUF ASCO Receive Buffer Register read only SOTIC ASCO Transmit Interrupt Control Register SORIC ASCO Receive Interrupt Control Register SOTBIC ASCO Transmit Buffer Interrupt Control Reg SOEIC ASCO Error Interrupt Control Register Figure 11 1 SFRs and Port Pins associated with ASCO The operating mode of the serial channel ASCO is controlled by its bitaddressable control register SOCON This register contains control bits for mode and error check selection and status flags for error identification Semiconductor Group 11 1 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI SOCON FFBO D8 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 so SO so rw rw rw rw rw rw rw rw rw rw rw rw rw Bit Function SOM ASCO Mode Control 000 8 bit data synchronous operation 001 8 bit data async operation 010 Reserved Do not use this combination 011 7 bit data parity async operation 100 9 bit data async operation 101 8 bit data wake up bit async operation 110 Reserved Do not use this combination 111 8 bit data parity async
387. tiplexes address and data a 16 bit data bus requires a word latch the least significant address line AO is not relevant for word accesses The upper address lines An A16 are permanently output on Port 4 if segmentation is enabled and do not require latches The EBC initiates an external access by generating the Address Latch Enable signal ALE and then placing an address on the bus The falling edge of ALE triggers an external latch to capture the address After a period of time during which the address must have been latched externally the address is removed from the bus The EBC now activates the respective command signal RD WR WRL WRH Data is driven onto the bus either by the EBC for write cycles or by the external memory peripheral for read cycles After a period of time which is determined by the access time of the memory peripheral data become valid Read cycles Input data is latched and the command signal is now deactivated This causes the accessed device to remove its data from the bus which is then tri stated again Write cycles The command signal is now deactivated The data remain valid on the bus until the next external bus cycle is started Bus Cycle Segment P4 Address ALE N BUS PO 7 Address I o Dam OO X a5 p MCT02060 Figure 9 2 Multiplexed Bus Cycle Semiconductor Group 9 3 1998 06 01 SIEMENS The External Bus Interface C161RI De
388. to another 4 Interruptable Multiple Cycle Instructions Reduced interrupt latency is provided by allowing multiple cycle instructions multiply divide to be interruptable With an interrupt response time within a range from just 5 to 10 CPU clock cycles in case of internal program execution the C161RI is capable of reacting very fast on non deterministic events Its fast external interrupt inputs are sampled every CPU clock cycle and allow to recognize even very short external signals The C161RI also provides an excellent mechanism to identify and to process exceptions or error conditions that arise during run time so called Hardware Traps Hardware traps cause an immediate non maskable system reaction which is similiar to a standard interrupt service branching to a dedicated vector table location The occurrence of a hardware trap is additionally signified by an individual bit in the trap flag register TFR Except for another higher prioritized trap service being in progress a hardware trap will interrupt any current program execution In turn hardware trap services can normally not be interrupted by standard or PEC interrupts Software interrupts are supported by means of the TRAP instruction in combination with an individual trap interrupt number Semiconductor Group 2 6 1998 05 01 SIEMENS Architectural Overview C161RI 2 2 The On chip System Resources The C161RI controllers provide a number of powerful system
389. trol T3EUD Capture Interrupt Request T4 TAIN J Mode oer Control y oK 2 n23 10 Interrupt GPT1 Timer T4 Request T4EUD Ji MCB02141 Figure 10 2 GPT1 Block Diagram Semiconductor Group 10 2 1998 05 01 SIEMENS The General Purpose Timer Units C161RI GPT1 Core Timer T3 The core timer T3 is configured and controlled via its bitaddressable control register T3CON T3CON FF42 A1 SFR Reset Value 0000 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 T3 T3 i z rw rw rw rw rw rw rw Bit Function TSI Timer 3 Input Selection Depends on the operating mode see respective sections T3M Timer 3 Mode Control Basic Operating Mode 000 Timer Mode 001 Counter Mode 010 Gated Timer with Gate active low 011 Gated Timer with Gate active high 100 Reserved Do not use this combination 101 Reserved Do not use this combination 110 Incremental Interface Mode 111 Reserved Do not use this combination T3R Timer 3 Run Bit TSR 2 0 Timer Counter 3 stops TSR2 1 Timer Counter 3 runs T3UD Timer 3 Up Down Control T3UDE Timer 3 External Up Down Enable TSOE Alternate Output Function Enable T30E 0 Alternate Output Function Disabled T30E 2 1 Alternate Output Function Enabled TSOTL Timer 3 Output Toggle Latch Toggles on each overflow underflow of T3 Can be set or reset by software For the effects of bits T2UD and T3UDE refer to the direction ta
390. tting of the interrupt request flag N 1 N 2 will be executed after the PEC data transfer Note When instruction N reads any of the PEC control registers PECC7 PECCO while a PEC request wins the current round of prioritization this round is repeated and the PEC data transfer is started one cycle later The minimum PEC response time is 3 states 6 TCL This requires program execution from the internal code memory no external operand read requests and setting the interrupt request flag during the last state of an instruction cycle When the interrupt request flag is set during the first state of an instruction cycle the minimum PEC response time under these conditions is 4 state times 8 TCL Semiconductor Group 5 18 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI The PEC response time is increased by all delays of the instructions in the pipeline that are executed before starting the data transfer including N When internal hold conditions between instruction pairs N 2 N 1 or N 1 N occur the minimum PEC response time may be extended by 1 state time for each of these conditions When instruction N reads an operand from the internal code memory or when N is a call return trap or MOV Rn Rm data16 instruction the minimum PEC response time may additionally be extended by 2 state times during internal code memory program execution In case instruction N reads the PSW and instruction N 1 has an effect o
391. uction following the IDLE instruction accepted N IDLE instruction wo Denied PEC Request Vv ps Figure 19 2 Transitions between Idle mode and Active Mode Idle mode can also be terminated by a Non Maskable Interrupt i e a high to low transition on the NMI pin After Idle mode has been terminated by an interrupt or NMI request the interrupt system performs a round of prioritization to determine the highest priority request In the case of an NMI request the NMI trap will always be entered Any interrupt request whose individual Interrupt Enable flag was set before Idle mode was entered will terminate Idle mode regardless of the current CPU priority The CPU will not go back into Idle mode when a CPU interrupt request is detected even when the interrupt was not serviced because of a higher CPU priority or a globally disabled interrupt system IEN 0 The CPU will only go back into Idle mode when the interrupt system is globally enabled IEN 1 and a PEC service on a priority level higher than the current CPU level is requested and executed Note An interrupt request which is individually enabled and assigned to priority level O will terminate Idle mode The associated interrupt vector will not be accessed however The watchdog timer may be used to monitor the Idle mode an internal reset will be generated if no interrupt or NMI request occurs before the watchdog timer overflows To prevent the watchdog time
392. ude Normal Interrupt Processing The CPU temporarily suspends the current program execution and branches to an interrupt service routine in order to service an interrupt requesting device The current program status IP PSW in segmentation mode also CSP is saved on the internal system stack A prioritization scheme with 16 priority levels allows the user to specify the order in which multiple interrupt requests are to be handled Interrupt Processing via the Peripheral Event Controller PEC A faster alternative to normal software controlled interrupt processing is servicing an interrupt requesting device with the C161RI s integrated Peripheral Event Controller PEC Triggered by an interrupt request the PEC performs a single word or byte data transfer between any two locations in segment 0 data pages 0 through 3 through one of eight programmable PEC Service Channels During a PEC transfer the normal program execution of the CPU is halted for just 1 instruction cycle No internal program status information needs to be saved The same prioritization scheme is used for PEC service as for normal interrupt processing PEC transfers share the 2 highest priority levels Trap Functions Trap functions are activated in response to special conditions that occur during the execution of instructions A trap can also be caused externally by the Non Maskable Interrupt pin NMI Several hardware trap functions are provided for handling erroneous conditi
393. ul CPU core and a set of peripheral units into one chip but also connects the units in a very efficient way One of the four buses used concurrently on the C161Hl is the XBUS an internal representation of the external bus interface This bus provides a standardized method of integrating application specific peripherals to produce derivates of the standard C161Hl XRAM xBUSModue PcBusModule ett l Ez ee EA Fs ALL o s l U gt o o EH Interrupt Controller PORTO SSC RTC Ext OSC Figure 2 1 C161RI Functional Block Diagram Semiconductor Group 2 1 1998 05 01 SIEMENS Architectural Overview C161RI 2 4 Basic CPU Concepts and Optimizations The main core of the CPU consists of a 4 stage instruction pipeline a 16 bit arithmetic and logic unit ALU and dedicated SFRs Additional hardware is provided for a separate multiply and divide unit a bit mask generator and a barrel shifter Internal SP STKOV TKN Exec Unit Mul Div HW Instr Ptr Bit Mask Gen General Instr Reg Purpose ROM 4 Stage 16 bit Pipeline Registers Barrel Shifter 9 ee ee ee ee eS dC PSW SYSCON Data Page Ptr Code Seg Ptr MCB02147 Figure 2 2 CPU Block Diagram To meet the demand for greater performance and flexibility a number of areas has been optimized in the processor core Functional blocks in the CPU core are controlled by
394. umbers are always represented as the 2 s complement of the corresponding positive number The range of signed numbers extends from 8000 to 7FFF for the word data type or from 80 to 7F for the byte data type For Boolean bit operations with only one operand the N flag represents the previous state of the specified bit For Boolean bit operations with two operands the N flag represents the logical XORing of the two specified bits C Flag After an addition the C flag indicates that a carry from the most significant bit of the specified word or byte data type has been generated After a subtraction or a comparison the C flag indicates a borrow which represents the logical negation of a carry for the addition This means that the C flag is set to 1 if no carry from the most significant bit of the specified word or byte data type has been generated during a subtraction which is performed internally by the ALU as a 2 s complement addition and the C flag is cleared when this complement addition caused a carry The C flag is always cleared for logical multiply and divide ALU operations because these operations cannot cause a carry anyhow For shift and rotate operations the C flag represents the value of the bit shifted out last If a shift count of zero is specified the C flag will be cleared The C flag is also cleared for a prioritize ALU operation because a 1 is never shifted out of the MSB during the normalizatio
395. urrently not used Data Valid SDA stable during the high phase of SCL SDA then represents the transferred bit There is one clock pulse for each transferred bit of data During data transfers SDA may only change while SCL is low see below Start Transfer A falling edge on SDA X while SCL is high indicates a start condition This start condition initiates a data transfer over the IPC bus Stop Transfer A rising edge on SDA lt while SCL is high indicates a stop condition This stop condition terminates a data transfer Between a start condition and a stop condition an arbitrary number of bytes may be transferred The figure below gives examples for these bus conditions Semiconductor Group 17 2 1998 05 01 SIEMENS The I2C Bus Module C161RI Internal Clock n 5 Start Condition SDA SCL Data Acknowledge Bit SDA SCL Repeated Start SDA SCL Stop Condition SDA SCL The high level of the signal is verified If the signal is low the previous state Ti is repeated The length of each state is 1 256 CPU clock cycles as defined by bitfield BRP in register ICCFG in the above axample n 5 ie BRP 04 Figure 17 2 PC Bus Conditions Semiconductor Group 17 3 MCD03901 1998 05 01 SIEMENS The I2C Bus Module C161RI 17 2 The Physical PC Bus Interface Communication via the C Bus uses two bidirectional lines the serial data line SDA and the serial clock line SC
396. use an interrupt request Semiconductor Group 10 6 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Timer 3 in Counter Mode Counter mode for the core timer T3 is selected by setting bit field T3M in register T3CON to 001 In counter mode timer T3 is clocked by a transition at the external input pin T3IN The event causing an increment or decrement of the timer can be a positive a negative or both a positive and a negative transition at this pin Bit field T3l in control register T3CON selects the triggering transition see table below Edge Select a a 1 Up TxR 4 Down xis Txl TxOTL I D TxOUT j MUX TxOE END EXOR 1 T3IN P356 TxUDE feo TSEUD P3 4 T3OUT P3 3 d Figure 10 5 Block Diagram of Core Timer T3 in Counter Mode GPT1 Core Timer T3 Counter Mode Input Edge Selection T3I Triggering Edge for Counter Increment Decrement 000 None Counter T3 is disabled 001 Positive transition rising edge on T3IN 010 Negative transition falling edge on T3IN 011 Any transition rising or falling edge on T3IN 1XX Reserved Do not use this combination For counter operation pin T3IN must be configured as input i e the respective direction control bit DPx y must be 0 The maximum input frequency which is allowed in counter mode is fe py 16 To ensure that a transition of the count input signal which is applied to T3IN is correctly recognized its level sh
397. uses the same effects as if it had been set by hardware The reset functions hardware software watchdog may be regarded as a type of trap Reset functions have the highest system priority trap priority III Class A traps have the second highest priority trap priority II on the 3rd rank are class B traps so a class A trap can interrupt a class B trap If more than one class A trap occur at a time they are prioritized internally with the NMI trap on the highest and the stack underflow trap on the lowest priority All class B traps have the same trap priority trap priority I When several class B traps get active at a time the corresponding flags in the TFR register are set and the trap service routine is entered Since all class B traps have the same vector the priority of service of simultaneously occurring class B traps is determined by software in the trap service routine A class A trap occurring during the execution of a class B trap service routine will be serviced immediately During the execution of a class A trap service routine however any class B trap occurring will not be serviced until the class A trap service routine is exited with a RETI instruction In this case the occurrence of the class B trap condition is stored in the TFR register but the IP value of the instruction which caused this trap is lost In the case where e g an Undefined Opcode trap class B occurs simultaneously with an NMI trap class A both t
398. ut NOT by software modifications of T3OTL MCB02035 Figure 10 12 GPT1 Auxiliary Timer in Reload Mode Upon a trigger signal T3 is loaded with the contents of the respective timer register T2 or T4 and the interrupt request flag T2IR or T4IR is set Note When a T3OTL transition is selected for the trigger signal also the interrupt request flag T3IR will be set upon a trigger indicating T3 s overflow or underflow Modifications of T3OTL via software will NOT trigger the counter function of T2 T4 The reload mode triggered by T3OTL can be used in a number of different configurations Depending on the selected active transition the following functions can be performed If both a positive and a negative transition of TSOTL is selected to trigger a reload the core timer will be reloaded with the contents of the auxiliary timer each time it overflows or underflows This is the standard reload mode reload on overflow underflow If either a positive or a negative transition of T3OTL is selected to trigger a reload the core timer will be reloaded with the contents of the auxiliary timer on every second overflow or underflow Semiconductor Group 10 15 1998 05 01 SIEMENS The General Purpose Timer Units C161RI Using this single transition mode for both auxiliary timers allows to perform very flexible pulse width modulation PWM One of the auxiliary timers is programmed to reload the core timer on a positive transition of TSOTL
399. ute branch to this area Note As a rule instructions that change ROM mapping should be executed from internal RAM or external memory e BUSCON ADDRSEL The instruction following an instruction that changes the properties of an external address area cannot access operands within the new area In these cases an instruction that does not access this address area should be inserted Code accesses to the new address area should be made after an absolute branch to this area Note As a rule instructions that change external bus properties should not be executed from the respective external memory area e Timing Instruction pipelining reduces the average instruction processing time in a wide scale from four to one machine cycles mostly However there are some rare cases where a particular pipeline situation causes the processing time for a single instruction to be extended either by a half or by one machine cycle Although this additional time represents only a tiny part of the total program execution time it might be of interest to avoid these pipeline caused time delays in time critical program modules Besides a general execution time description the following section provides some hints on how to optimize time critical program parts with regard to such pipeline caused timing particularities Semiconductor Group 4 8 1998 05 01 SIEMENS The Central Processing Unit CPU C161RI 4 2 Bit Handling and Bit Protection The C161RI p
400. utputs the 16 bit intra segment address as an alternate output function PORTO is then switched to high impedance input mode to read the incoming instruction or data In 8 bit data bus mode two memory cycles are required for word accesses the first for the low byte and the second for the high byte of the word During write cycles PORTO outputs the data byte or word after outputting the address During external accesses in demultiplexed bus modes PORTO reads the incoming instruction or data word or outputs the data byte or word Alternate Function a b c d POH 7 D15 A15 AD15 POH 6 D14 A14 AD14 POH 5 D13 A13 AD13 POH POH 4 D12 A12 AD12 0 POH 3 D11 A11 AD11 POH 2 D10 A10 AD10 POH 1 D9 A9 AD9 POH O D8 A8 AD8 PORTO POL 7 D7 D7 AD7 AD7 POL 6 D6 D6 AD6 AD6 POL 5 D5 D5 AD5 AD5 POL 4 D4 D4 AD4 AD4 POL POL 3 D3 D3 AD3 AD3 POL 2 D2 D2 AD2 AD2 POL 1 D1 D1 AD1 AD1 POL O DO DO ADO ADO General Purpose 8 bit 16 bit 8 bit 16 bit Input Output Demux Bus Demux Bus MUX Bus MUX Bus Figure 7 4 PORTO IO and Alternate Functions Semiconductor Group 7 7 1998 05 01 SIEMENS Parallel Ports C161RI When an external bus mode is enabled the direction of the port pin and the loading of data into the port output latch are controlled by the bus controller hardware The input of the port output latch is disconnected from the internal bus and is switched to the line labeled Alternate Data Output via a multiplexer The al
401. w rw rw rw r Bit Function Operating Mode SSCEN 1 SSCBC SSC Bit Count Field Shift counter is updated with every shifted bit Do not write to SSCTE SSC Transmit Error Flag 1 Transfer starts with the slave s transmit buffer not being updated SSCRE SSC Receive Error Flag dus Reception completed before the receive buffer was read SSCPE SSC Phase Error Flag Ee Received data changes around sampling clock edge SSCBE SSC Baudrate Error Flag 1 More than factor 2 or 0 5 between Slave s actual and expected baudrate SSCBSY SSC Busy Flag Set while a transfer is in progress Do not write to SSCMS SSC Master Select Bit 0 Slave Mode Operate on shift clock received via SCLK he Master Mode Generate shift clock and output it via SCLK SSCEN SSC Enable Bit 1 Transmission and reception enabled Access to status flags and M S control Note The target of an access to SSCCON control bits or flags is determined by the state of SSCEN prior to the access i e writing C0574 to SSCCON in programming mode SSCEN 0 will initialize the SSC SSCEN was 0 and then turn it on SSCEN 1 When writing to SSCCON make sure that reserved locations receive zeros The shift register of the SSC is connected to both the transmit pin and the receive pin via the pin control logic see block diagram Transmission and reception of serial data is synchronized and takes place at the same time i e the same
402. west addresses in code segment 0 of the address space Each entry occupies 2 words except for the reset vector and the hardware trap vectors which occupy 4 or 8 words The table below lists all sources that are capable of requesting interrupt or PEC service in the C161RI the associated interrupt vectors their locations and the associated trap numbers It also lists the mnemonics of the affected Interrupt Request flags and their corresponding Interrupt Enable flags The mnemonics are composed of a part that specifies the respective source followed by a part that specifies their function IR Interrupt Request flag IE Interrupt Enable flag Note Each entry of the interrupt vector table provides room for two word instructions or one doubleword instruction The respective vector location results from multiplying the trap number by 4 4 bytes per entry All interrupt nodes that are currently not used by their associated modules or are not connected to a module in the actual derivative may be used to generate software controlled interrupt requests by setting the respective IR flag Semiconductor Group 5 2 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI Source of Interrupt or PEC Request Enable Interrupt Vector Trap Service Request Flag Flag Vector Location Number Fast External Interrupt 0 CC8IR CC8IE CC8INT 00 0060 18 2
403. which cause hardware traps Fast External Interrupts The input pins that may be used for external interrupts are sampled every 16 TCL i e external events are scanned and detected in timeframes of 16 TCL The C161RI provides 8 interrupt inputs that are sampled every 2 TCL so external events are captured faster than with standard interrupt inputs The8 pins of Port 2 P2 15 P2 8 can individually be programmed to this fast interrupt mode where also the trigger transition rising falling or both can be selected The External Interrupt Control register EXICON controls this feature for all 8 pins EXICON F1C0 E0 ESFR Reset Value 0000 1 14 5 13 12 3t 10 9 8 7 6 5 4 3 2 1 0 rw rw rw rw rw rw rw rw Bit Function EXIxES External Interrupt x Edge Selection Field x 7 0 0 0 Fast external interrupts disabled standard mode 0 1 Interrupt on positive edge rising 1 0 Interrupt on negative edge falling 1 1 Interrupt on any edge rising or falling Note The fast external interrupt inputs are sampled every 2 TCL The interrupt request arbitration and processing however is executed every 8 TCL Semiconductor Group 5 22 1998 05 01 SIEMENS Interrupt and Trap Functions C161RI The interrupt control registers listed below CC151C CC8IC control the fast external interrupts of the C161RI These fast external interrupt nodes and vectors are named according to the C167 s CAPCOM channels CC15 CC8
404. with post increment by either 1 or 2 CMPI1 CMPI2 Comparison of two words with post decrement by either 1 or 2 CMPD1 CMPD2 Semiconductor Group 22 1 1998 05 01 SIEMENS Instruction Set Summary C161RI Boolean Bit Manipulation Instructions Manipulation of a maskable bit field in either the high or the low byte of a word BFLDH BFLDL Setting a single bit to 1 BSET Clearing a single bit to 0 BCLR Movement of a single bit BMOV Movement of a negated bit BMOVN ANDing of two bits BAND ORing of two bits BOR XORing of two bits BXOR Comparison of two bits BCMP Shift and Rotate Instructions Shifting right of a word SHR Shifting left of a word SHL Rotating right of a word ROR Rotating left of a word ROL Arithmetic shifting right of a word sign bit shifting ASHR Prioritize Instruction Determination of the number of shift cycles required to normalize a word operand floating point support PRIOR Data Movement Instructions Standard data movement of a word or byte MOV MOVB Data movement of a byte to a word location with either sign or zero byte extension MOVBS MOVBZ Note The data movement instructions can be used with a big number of different addressing modes including indirect addressing and automatic pointer in decrementing System Stack Instructions Pushing of a word onto the system stack PUSH Popping of a word from the syste
405. xternal pins XPEN XBUS Peripheral Enable Bit 0 Accesses to the on chip X Peripherals and their functions are disabled 1 The on chip X Peripherals are enabled and can be accessed BDRSTEN Bidirectional Reset Enable Bit 0 Pin RSTIN is an input only 1 Pin RSTIN is pulled low during the internal reset sequence after a software or WDT reset CSCFG Chip Select Configuration Control 0 Latched CS mode The CS signals are latched internally and driven to the enabled port pins synchronously 1 Unlatched CS mode The CS signals are directly derived from the address and driven to the enabled port pins WRCFG Write Configuration Control Set according to pin POH O during reset 0 Pins WR and BHE retain their normal function 1 Pin WR acts as WRL pin BHE acts as WRH Semiconductor Group 9 17 1998 06 01 SIEMENS The External Bus Interface C161RI Bit Function CLKEN System Clock Output Enable CLKOUT 0 CLKOUT disabled pin may be used for general purpose IO 1 CLKOUT enabled pin outputs the system clock signal BYTDIS Disable Enable Control for Pin BHE Set according to data bus width 0 Pin BHE enabled 1 Pin BHE disabled pin may be used for general purpose IO ROMEN Internal ROM Enable Set according to pin EA during reset 0 Internal ROM disabled accesses to the ROM area use the external bus 1 Internal ROM enabled SGTDIS Segmentation Disable Enable Control 0 Segmentation enabled CSP is
406. y i e RTC on or off and on the current that flows through the port drivers To minimize the consumed current the RTC and or all pin drivers can be disabled pins switched to tristate via a central control bitfield in register SYSCONa If an application requires one or more port drivers to remain active even in Power Down mode also individual port drivers can be disabled simply by configuring them for input The bus interface pins can be separately disabled by releasing the external bus disable all address windows by clearing the BUSACT bits and switching the ports to input if necessary Of course the required software in this case must be executed from internal memory Semiconductor Group 19 4 1998 05 01 SIEMENS Power Management C161RI Status of Output Pins during Power Reduction Modes During Idle mode the CPU clocks are turned off while all peripherals continue their operation in the normal way Therefore all ports pins which are configured as general purpose output pins output the last data value which was written to their port output latches If the alternate output function of a port pin is used by a peripheral the state of the pin is determined by the operation of the peripheral Port pins which are used for bus control functions go into that state which represents the inactive state of the respective function e g WR or to a defined state which is based on the last bus access e g BHE Port pins which are used as extern
407. y clearing bit SOREN A currently received byte is completed including the generation of the receive interrupt request and an error interrupt request if appropriate Writing to the transmit buffer register while a reception is in progress has no effect on reception and will not start a transmission If a previously received byte has not been read out of the receive buffer register at the time the reception of the next byte is complete both the error interrupt request flag SOEIR and the overrun error status flag SOOE will be set provided the overrun check has been enabled by bit SOOEN Semiconductor Group 11 9 1998 05 01 Sl EM ENS The Asynchronous Synchronous Serial Interface C161RI 11 3 Hardware Error Detection Capabilities To improve the safety of serial data exchange the serial channel ASCO provides an error interrupt request flag which indicates the presence of an error and three selectable error status flags in register SOCON which indicate which error has been detected during reception Upon completion of a reception the error interrupt request flag SOEIR will be set simultaneously with the receive interrupt request flag SORIR if one or more of the following conditions are met Ifthe framing error detection enable bit SOFEN is set and any of the expected stop bits is not high the framing error flag SOFE is set indicating that the error interrupt request is due to a framing error Asynchronous mode only e Ifthe parity e
408. ypically during the initialization of the system The bus configuration BTYP for the default address range BUSCONO is selected via PORTO during reset provided that pin EA is low during reset Otherwise BUSCONO may be programmed via software just like the other BUSCON registers The 16 MByte address space of the C161RI is divided into 256 segments of 64 KByte each The 16 bit intra segment address is output on PORTO for multiplexed bus modes or on PORT1 for demultiplexed bus modes When segmentation is disabled only one 64 KByte segment can be used and accessed Otherwise additional address lines may be output on Port 4 addressing up to 8 MByte and or several chip select lines may be used to select different memory banks or peripherals These functions are selected during reset via bitfields SALSEL and CSSEL of register RPOH respectively Note Bit SGTDIS of register SYSCON defines if the CSP register is saved during interrupt entry segmentation active or not segmentation disabled Semiconductor Group 9 2 1998 06 01 SIEMENS The External Bus Interface C161RI Multiplexed Bus Modes In the multiplexed bus modes the 16 bit intra segment address as well as the data use PORTO The address is time multiplexed with the data and has to be latched externally The width of the required latch depends on the selected data bus width i e an 8 bit data bus requires a byte latch the address bits A15 A8 on POH do not change while POL mul
409. ys except for GPRs Ordered by address to check which register a given address references Ordered by register name to find the location of a specific register 21 1 Register Description Format In the respective chapters the function and the layout of the SFRs is described in a specific format which provides a number of details about the described special function register The example below shows how to interpret these details A word register looks like this REG NAME Hb n E SFR Reset Value 14 11 write read only only Bit Function bit field name Explanation of bit field name Description of the functions controlled by this bit field A byte register looks like this REG NAME A16 A8 E SFR Reset Value Elements REG NAME Name of this register A16 A8 Long 16 bit address Short 8 bit address SFR ESFR XRegRegister space SFR ESFR or External XBUS Register idle aon Register contents after reset 0 1 defined value X undefined U unchanged undefined X after power up hwbit Bits that are set cleared by hardware are marked with a shaded access box Semiconductor Group 21 1 1998 05 01 SIEMENS The Register Set C161RI 21 2 CPU General Purpose Registers GPRs The GPRs form the register bank that the CPU works with This register bank may be located anywhere within the internal RAM via the Context Pointer CP Due to the addressing mechanism GPR
410. ystem stack is defined via the STKUN and STKOV pointers The underflow and overflow traps in this case serve for fatal error detection only For the linear stack option all modifiable bits of register SP are used to access the physical stack Although the stack pointer may cover addresses from 00 F000 up to 00 FFFE the physical system stack must be located within the internal RAM and therefore may only use the address range 00 F600 to O0 FDFE It is the user s responsibility to restrict the system stack to the internal RAM range Note Avoid stack accesses below the IRAM area ESFR space and reserved area and within address range 00 FE00 and 00 FFFE SFR space Otherwise unpredictable results will occur Semiconductor Group 20 7 1998 05 01 SIEMENS System Programming C161RI User Stacks User stacks provide the ability to create task specific data stacks and to off load data from the system stack The user may push both bytes and words onto a user stack but is responsible for using the appropriate instructions when popping data from the specific user stack No hardware detection of overflow or underflow of a user stack is provided The following addressing modes allow implementation of user stacks Rw Rb or Rw Rw Pre decrement Indirect Addressing Used to push one byte or word onto a user stack This mode is only available for MOV instructions and can specify any GPR as the user stack pointer Rb Rw o

Infineon C161RI User`s Manual

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