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Rabbit 4000 Microprocessor Designer`s Handbook

1. 8 2 1 Steps to Enable and Set Up Cloning The step by step instructions to enable and set up cloning on the master are in Technical Note 207 In brief the steps break down to attaching the programming cable running Dynamic C making any desired changes to the cloning macros and then compiling the BIOS and user program to the master The only cloning macro that must be changed is ENABLE CLONING since the default condition is that cloning is disabled 8 2 2 Steps to Perform Cloning Once cloning is enabled and set up on the master controller detach the programming cable and attach the cloning board to the master and the clone Make sure the master end of the cloning board is connected to the master controller the cloning board is not reversible and that pin 1 lines up correctly on both ends Once this is done reset the master by pressing Reset on the cloning board The cloning process will begin 8 2 3 LED Patterns While cloning is in progress the LED on the Cloning board will toggle on and off every 1 1 5 seconds When cloning completes the LED stays on If any error occurs the LED will start blinking quickly Older versions of cloning used different LED patterns but the Rabbit 4000 is only supported by versions that use the pattern described here 64 rabbit com BIOS Support for Program Cloning 8 3 Cloning Questions The following subsections answer questions about different aspects of cloning 8 3 1 MAC Address Some Ethern
2. BOARD TYPE This is read from the System ID block or defaulted to 0x100 the BL1810 JackRabbit board if no System ID block is present This can be used for conditional compilation based on board type CC VER Gives the Dynamic C version in hex i e version 10 21 is OXOA21 _CPU TE This macro identifies the CPU type e g R4000 is the Rabbit 4000 microprocessor FLASH RAM Used for conditional compilation of the BIOS to distinguish between compiling to RAM and compiling to flash These are set in the Compiler tab in the Options Project Options dialog RAM SIZE FLASH SIZE Used to set the MMU registers and code and data sizes available to the compiler The values of these macros represent the number of 0x 1000 blocks of memory available _ SEPARATE INST DATA Flag for identifying whether separate I amp D space is enabled or disabled FLASH COMPILE RAM COMPILE FAST RAM COMPILE Used to determine compile mode in code See the Dynamic C User Manual for other internally defined macros 6 4 Modifying the BIOS The BIOS that is supplied with Dynamic C may be modified or replaced Prudence demands that any changes made to this important piece of software be done one step at a time in order to more easily detect and isolate any problems that may arise RabbitBios c is still used but is more of a wrapper file that brings in some configuration and defini tion fil
3. file in the main directory where Dynamic C was installed for use by the compiler and pilot BIOS See the top of the file for more information 10 2 Writing Your Own Flash Driver Rabbit does not support using a flash memory that is not listed in TN226 and that does not use the same standard 8 bit JEDEC write sequences as one of the supported flash memories If you must use such a flash memory the flash driver supplied with Dynamic C LIB BIOSLIB FLASHWR LIB provides a model for writing your own flash driver Rabbit 4000 Designer s Handbook rabbit com 73 74 rabbit com Supported Flash Memories Semiconductor 11 Troubleshooting Tips for New Rabbit Based Systems If the Rabbit design conventions were followed and Dynamic C cannot establish target communications with the Rabbit 4000 based system there are a number of initial checks and some diagnostic tests that can help isolate the problem 11 1 Initial Checks Perform the first two checks with the RESET line tied to ground For the 128 pin LQFP package the RESET line is pin 46 1 With a voltmeter check for Vpp and Ground including Vgarr on the appropriate pins 2 With an oscilloscope check the 32 768 kHz oscillator on CLK32K pin 49 Make sure that it is oscillat ing and that the frequency is correct 3 With an oscilloscope check the main system oscillator by observing the signal CLK pin 2 With the reset held high and no existing program in the fla
4. Rabbit 4000 Microprocessor Designer s Handbook 019 0156 070920 D The latest revision of this manual is available on the Rabbit Web site www tabbit com for free unregistered download in l Rabbit 4000 Microprocessor Designer s Handbook Part Number 019 0156 070920 D Printed in U S A 2007 Rabbit All rights reserved No part of the contents of this manual may be reproduced or transmitted in any form or by any means without the express written permission of Rabbit Permission is granted to make one or more copies as long as the copyright page contained therein is included These copies of the manuals may not be let or sold for any reason without the express written permission of Rabbit Rabbit reserves the right to make changes and improvements to its products without providing notice Trademarks Rabbit and Dynamic C are registered trademarks of Rabbit Semiconductor Chapter 1 1 1 Chapter 2 2 1 2 2 2 3 2 4 2 5 Chapter 3 3 1 3 2 3 3 3 4 3 5 Chapter 4 4 1 4 2 Chapter 5 5 1 5 2 5 3 MAM Hon cies ET EE EE EE EE EER 1 Summary of Design Conventions cccccesecsseeseesseeseceseeseeeseeseceseesecesecsecesecsaeesecesesseeeaeeaeseaeeaseeseseenseeaes 1 Rabbit Hardware Design Overview asse sig NE ee NR ee GR ee ee Ge Ee ee RS 3 BESEM AS SERE OE EE N 3 2 1 1 Rabbit Programming Connector ccccccccesesssceseeeeeseeseceseeseeeceeecesessecesecaeeesesseeeseeeseseeese
5. 3 4 36 programming cable COMNECHOT ees f VSO SR EE 15 82 DHCP CLIENT_ID_MAC Be ae ED 37 Sleepy Ode 72 diagnostic LOSS e EE 75 binary compatibility eeeee see ese ee ee ee ee ee ee ee ee ee 58 DTR line ee EO EE EE ie 15 DIOS ES ER es GOED Ge RD AG 31 Dynamic C start sequence eeue 15 conditional compilation ee 34 Dynamic C version sesse sees ee ee RA ee ee 34 flowchart sis ER ER ee oe As ee ee DE ST 33 E IMOGUY ING R sentrerer er ersin is nains 34 Wait LOOP f isssssccsecgscsseesacesceusziaedzssasicssdeviessdsacesapesees 8 FVD eee heed ee RE ee esas 11 board type st GE GE se Se ee ee Se Ge ee 34 ENABLE CLONING sscaniasnersnntiaienia 35 boot DIOCKS eirp see ee ee Ge ee Re Re Re Re Re 57 ENABLE SPREADER i iese sesse sesse see se see se ee ee 36 boot ROM EE EE cs EERE desta 14 F c EETS E E ed 8 67 calibration constants iese ee ee Re RA Re AA 51 finite state machine ee RR RR Re 16 CAPACITANCE Re oroesi serei osis tisis 10 67 TiM WATE e213 22005 vest eseis stceseceenertenvesssaitavsceenssteseshaues 13 Ceramic resonatOF ee ee RR RR Re Re Re ee 4 flash chip selet EE ER eg ee EO DEd De es ee 3 CUSTOM drIVEr ees ee RA RA Re Re Re 73 self timed mode oo ee ek Re AR RR 68 Supported devices ee RR RA Re 73 SHOT ModE EE NE iinr 68 write method oo ees ee AR RR ee RA 16 CLK di ER EE IE ie 75 AE LES AR N N EE 36 clock input ees AR Re Re RA EA Re ee Re Re ee 71 Fletcher algorithm esse ee ee Re ee Re AR ee 16 CLOCK
6. DOUBLED ivre sees see nd es See se sek Ge Ee eb ee dig 35 floating Inputs issie EE RE RR DR Eg Nek ee BAR RE es N sg Eg 8 CLOCKS EE EE es A I 1 7 11 68 common crystal frequencies ees ee 3 H speed meee eevee EE wey ee 5 10 35 hardware reset onnenn prira 4 ClOMNG ER ON 3 4 35 63 OE EE N 67 70 l Cold BOGE ie ie EER Ee EE GEREEN Eg eg Di em eg 13 14 76 f conformal coating ii ee 71 io vet N 16 71 da OE EE 3 M crystal oscillator ees RA RR Re AR 3 32 kHz crystal oscillator external logic 71 MAC address ssseseesessseeeeseeseeseeeneeneenees 53 56 65 ESE eon EE Ee E E 32 35 macros defined internally CS1_ALWAYS ON iis kes se Ee ek ee 9 35 SEPARATE INST DATA esse esse sesse 34 BOARD TYPE esse see see se ese ee ee ee ee 34 CRUDE aa AE ed Ee Ee ee GE 34 PEAS HA ED cite ieee c teens 34 Rabbit 4000 Designer s Handbook rabbit com 83 FLASH SIZE ii is is ees eke sg ee ese ees 34 TE N S 34 RAM SIZE SE ees ited se ed ee oe leone 34 EE VER EO ee De eek ede ee G 34 MAX USERBLOCK SIZE iese sesse sesse se ese se ee 58 MBOCR_INVRT_A18 ees ee ee ee ee ee Re 37 MBOCR_INVRT_A19 ees ee ee ee ee Re 37 MBXER E EES SE Ee Ge ek GR ats 32 MECR ii ee ee ee Gen ke Ge de ees Ge ee eie 32 memory ACCESS el AE AT EN EE ER 10 bank control registers esse see ee ke ee 32 code in 2 flash Chips ee ee Re RR Re 36 data segment logical address eise see see 35 flash available e ese ee ee ee ee 36 58 line pe
7. Dynamic C defines macros that include information about compiling to RAM or flash and identifying memory device types memory sizes and board type The origin setup shown above differs from that included in the standard BIOS included with Dynamic C as the standard BIOS uses additional macro val ues for dealing with a wider range of boards and memory device types Physical Address Space Logical Address Space OxFFFFF OxFFFF xmemcode Ox9DDFF OxE000 stack rootdata OR DER watcode watcode 0xC5FF rootdata SE 0x20000 0x6000 rootcode xmemcode 0x0000 0x06000 rootcode 0x00000 NOTE This mapping assumes separate I amp D space is disabled 6 5 2 7 Origin Directives in Program Code To place programs in different places in root memory or to compile a boot strapping program such as a pilot BIOS or cold loader origin directives may be used in the user s program code For example the first line of a pilot BIOS program pilot c would be rcodorg rootcode 0x0 0x0 0x6000 apply A program with such an origin directive could only be compiled to a bin file because compiling it to the target would overwrite the running BIOS 48 rabbit com The Rabbit BIOS 6 5 2 8 Origin Directive to Reserve Blocks of Memory With the Rabbit 4000 the compiler generates an origin table that contains the blocks that are reserved for code and data origin or other non xalloc use With this change the method
8. ORG FLASH SIZE MAX _USERBLOCK_SIZE user_block Xmem Code i xmemcode ROOTCODE_SIZE Each origin declaration adds a little more to the overall mapping We recommend reading the code in memory layout 1ib and drawing memory maps like the one in Figure 6 2 This exercise will help to further your understanding of the complex topic of memory mapping 40 rabbit com The Rabbit BIOS 6 5 1 2 Origin Declaration Syntax Following is an EBNF Extended Backus Naur Form representation of the origin grammar facets declarations actions and macros Angle brackets lt and gt indicate non terminals while terminals are represented literally with these exceptions the definition and the and symbols are used to enclose optional synatx symbol represents a disjunction the represents a lt decl gt orgdef lt type gt lt name gt in lt name gt lt vector gt lt size gt locate lt int gt lt type gt lt phy_org gt slog org gt wcodorg resvorg lt phy org gt flashorg bbramorg fastramorg xconorg xcodorg xvarorg xmemorg lt log_org gt rconorg rcodorg rvarorg lt vector gt below lt offset gt above lt offset gt lt offset gt lt position gt log lt int gt lt name gt log lt int gt lt position gt phy lt int gt start end lt size gt size lt int gt to lt offset gt Or
9. 8 1 Overview of CLONING EE EO SSS Er a E OPES A EEE EA E E ETEei 63 Pe BAAS RE OER EE RE E RE N ER OE E 64 8 2 1 Steps to Enable and Set Up Cloning iese sesse ae AR ee Re Re Re ee GR ee ae Re ee ee Re RA Re Re ee ee 64 8 2 2 Steps to Perform Cloning 00 eceecesesssesceseeeeeeseeseesceaeccseseesesseceenecsesaeesessesseeaeeeseaseseeeeeeesaeeaeeaes 64 8 2 3 LED Vr AE RE NE EE NE EE EG 64 8 3 Cloning AL EE Oe EE as S EE Eas TE ETE e E OE EaR 65 8 3 I MAC Gl EE E ced hagas E E E E E EE 65 8 3 2 Different Flash Do SO N OE EN OE 65 8 3 3 Different Memory Ao AE EE N OE Oe Er 65 8 3 4 Design REStriGhOms AE EA EO ER ER eee 65 Chapter 9 Low Power Design and Support iese sees ea oe Re AA RA GR Re EA RA GR Re AE ee AA GR Re ee 67 9 1 Details of the Rabbit 4000 Low Power Features iese sesse se se ee ee GR GR GR Ge RA Gee ee ee Re GR Re GR Ge Re 68 9 1 1 Special Chip Select Features os cies iese se SS scavccahedscisesouas pcnescabeeleetcscvibnccasanaesacedesuevbine ke ee es gs 68 912 Reducing Clock Speed iste eek se eR Gee EE se Bep AE ad Ke seg aka hee dai AE AN EDE AGS bee GREG KEES 69 9 1 3 Preferred Crystal ConfiguratiON iese sesse ese se ee ee ek ee Re Re GR GR Ge Ge GR Ge AA Ge ee Re ee Re GR GR Re ee 69 9 2 To Further Decrease Power Consumption cccccescessesseesesesecseceseeseeesecseeenececesecaeenseeseenseseeeeaeeeeseneeaees 70 9 2 1 What To Do When There is Nothing To Do esse sesse se se ee Se Ge Re G
10. A block of bytes containing all fields from the start of the SysIDBlock struct up to but not including the reserved field is read from flash at address 0x40000 SIZE essentially filling the SysIDBlock struct except for the reserved field since the top 16 bytes have been read earlier The CRC field is saved in a local variable then set to 0x0000 A CRC check is then calculated for the entire ID block except the reserved field and compared to the saved value If they do not match the block is considered invalid and an error 3 is returned The CRC field is then restored The reserved field is avoided in the CRC check since its size may vary depending on the size of the ID block Determining the existence of a valid mirrored ID block may be slightly more complicated requiring the above sequence of events to be repeated at several locations below the top of the primary flash See Figure 7 2 below for complete details Not all fields are filled in different versions of the ID block The table below lists the first ID block version that filled each field and whether that field is absolutely required by Dynamic C for normal operation Much of the ID block data is useful but not critical Table 7 1 The System ID Block reer om ese ae Filled as start of bytes Description of Version Required block 00h 2 ID block version number 1 x 02h 2 Product ID 1 x 04h 2 Vendor ID 2 06h 7 Timestamp Y Y MM D H
11. BIOS comprises files that contain the code needed by the user program to interface with Dynamic C and the Rabbit hardware The BIOS may also contain a software interface to the user s particular hardware Certain drivers in the Dynamic C library suite require BIOS routines to perform tasks that are hardware dependent The BIOS also e Takes care of microprocessor system initialization such as the setup of memory e Provides the communications services required by Dynamic C for downloading code and performing debugging services such as setting breakpoints or examining data variables e Provides flash drivers The file RabbitBIOS c is a wrapper that permits a choice of which BIOS to compile A more modular design has been implemented by moving many of the configuration macros to separate configuration libraries The main BIOS file Stdbios c and the multiple configuration libraries are located in LIB Rabbit4000 BIOSLIB Dynamic C 10 21 introduces a change in the BIOS files Origin declarations have been redesigned One of the most dramatic results of the redesign is the ability to define relative relationships between origins dur ing the setup of memory This eliminates many of the macro definitions that were necessary before The supplied BIOS allows Dynamic C to boot up on any Rabbit based system that follows the basic design rules needed to support Dynamic C The BIOS requires either a 128 KB RAM or both a flash device and a 32 KB or l
12. a while and read frequently model Depending on the particular type of flash used the flash memory may wear out after it has been written approximately 10 000 to 100 000 times Rabbit 4000 Designer s Handbook rabbit com 17 5 1 2 SRAM Static RAM may or may not be battery backed If it is battery backed it retains its data when primary power is disconnected Static RAM chips typically used for Rabbit systems are 128 KB 256 KB 512 KB or 1 MB With the configurable physical memory of the Rabbit 4000 and support in Dynamic C 10 21 and later versions static RAM chips of 1MB and larger may also be used When the memory is battery backed power is supplied at 2 V to 3 V from a battery While preserving memory contents with battery power the shutdown circuitry must keep the chip select line high 5 1 3 Basic Memory Configuration A basic Rabbit system typically contains two or three static memory devices one flash memory device and one or two RAM devices Additional static memory devices may be added If an application requires stor ing a lot of data in flash memory it is recommended that a mass storage flash device be added such as NAND or serial flash Dynamic C contains drivers for both NAND and serial mass storage devices Alter natively another parallel flash memory device could be added although these devices tend to be smaller and more expensive and are not as suitable for larger amounts of data Note that some board designs may o
13. and data Starting with Dynamic C 10 21 the origin directives are in the library file memory layout 1ib which is use d in the BIOS For more information about the MMU and MIU registers please see the Rabbit 4000 Microprocessor User s Manual 32 rabbit com The Rabbit BIOS 6 2 BIOS Flowchart The following flowchart summarizes the functionality of the BIOS Start at address 0 Set up memory control and basic BIOS services Is the programming cable connected Divert to BIOS service Call user application program main Figure 6 1 BIOS Flowchart Start Dynamic C communications and state machine Act as master for cloning BIOS services for user application program Application Program NOTE To use the diagnostic port on the RCM43xx you must first reset the board and then plug in the Diag header of the programming cable NOTE If the programming cable is connected at power up the Rabbit will never execute the BIOS since the cable holds the board in coldboot mode Rabbit 4000 Designer s Handbook rabbit com 33 6 3 Internally Defined Macros Some macros used in the BIOS are defined internally by Dynamic C before the BIOS is compiled They are defined using tests done in the bootstrap loading or by reading variables set in the GUI or set by the CLC command line compiler Table 6 1 Partial List of Compiler Defined Macros Macro Name Macro Description
14. are needed e Set the macro RAMONLYBIOS to 1 in Lib Rabbit4000 BOARDTYPES LIB e When Dynamic C or the RFU first start they put the Rabbit 4000 based target board into bootstrap mode where it awaits data sent via triplets These programs then send triplets that map the lowest quadrant of physical memory to CS1 OE1 and WE1 in order to load a primary loader to RAM The first set of triplets loaded to the target is contained in a file called coldload bin This is the primary loader A different coldload bin is required to map the lowest memory quadrant to CS0 OEO and WEO The image file for this program is BIOS RAMonlyColdload bin To use it rename COLDLOAD BIN to COLDLOAD BAK and rename RAMonlyColdload bin to COLDLOAD BIN Later versions of Dynamic C may have a GUI method of choosing the cold loader e The primary loader loads a secondary loader pilot bin A different pilot BIOS is needed RAMonlypilot bin Rename pilot binto pilot bak and rename RAMonlypilot bin to pilot bin The secondary loader loads the Rabbit BIOS to RAM from the application program image file in the case of the RFU by compiling the BIOS straight to the target in the case of Dynamic C 30 rabbit com Rabbit Memory Organization Semiconductor 6 The Rabbit BIOS When Dynamic C compiles a user s program to a target board the BIOS Basic Input Output System is compiled first as an integral part of the user s program The
15. base and data segments can be adjusted by increasing or decreasing the BIOS macro DATAORG in increments of 0x1000 5 2 1 Definition of Terms The following definitions clarify some of the terms that will be encountered in this chapter Extended Code a k a xmem code Instructions located in the extended memory segment Extended Constants a k a xmem constants C constants located in the extended memory segment They are mixed together with the extended code Extended Memory a k a xmem Logical addresses in 0xE000 OxFFFF range Extended RAM RAM not used for root variables or stack Extended memory in RAM may be used for large buffers to save root RAM space The Dynamic C compiler supports the far keyword to allow C data types to be declared and defined in extended memory The code generation for the far data types makes use of the expanded Rabbit 4000 instructions and registers The function xalloc also allocates space in extended RAM memory See the Dynamic C User Manual for more information on the far keyword Far Constants C constants declared with the far keyword currently located in the extended memory segment The location of far constants may be changed in the future Root Code Instructions located in the base segment Root Constants C constants such as quoted strings initialized variables or data tables that are located in the base segment Root constants share space with root code unless separate I amp D sp
16. be controlled by OE1 and WE1 If this is done the RAM will consume more power while not battery backed than it would if it were run with dynamic chip select and a wait state If this special feature is used to speed up access time for battery backed RAM then no other memory chips should be connected to OE1 and WE1 Table 3 1 Typical Interface between the Rabbit 4000 and Memory Primary Flash SRAM Secondary Flash CSO OEO and WEO CS1 OE1 and WE1 CS2 OEO and WE0O Rabbit 4000 Designer s Handbook rabbit com 9 3 3 1 Memory Access Time Memory access time depends on the clock speed and the capacitive loading of the address and data lines Wait states can be specified by programming to accommodate slow memories for a given clock speed Wait states should be avoided with memory that holds programs because there is a significant slowing of the execution speed Wait states are far more important in the instruction memory than in the data memory since the great majority of accesses are instruction fetches Going from 0 to 1 wait states is about the same as reducing the clock speed by 30 Going from 0 to 2 wait states is worth approximately a 45 reduction in clock speed A table of memory access times required for various clock speeds is given in the Rabbit 4000 Microprocessor User s Manual 3 3 2 Interfacing External VO with Rabbit 4000 Designs The Rabbit 4000 provides on chip facilities for glueless interfacing
17. bit address is set to one to specify an internal I O write The remaining 15 bits specify the address If the write is to memory then the uppermost bit must be zero and the write must be to the first 32 KB of the memory space The user should see the 9 bytes transmitted at 2400 bps or 416 us per bit The status bit will initially toggle fairly rapidly during the transmission of the first triplet because the default setting of the status bit is to go low on the first byte of an opcode fetch While the triplets are being read instructions are being executed from the small cold boot program within the microprocessor The status line will go low after the first trip let has been read It will go high after the second triplet is read and return to low after the third triplet is read The status line will stay low until the sequence starts again If this test fails to function it may be that the programming connector is connected improperly or the proper pull up resistors are not installed on the SMODE lines Other possibilities are that one of the oscil lators is not working or is operating at the wrong frequency or the reset could be failing 11 2 2 1 Using seriallO exe This test is available as StatusTgl Diag one of the diagnostic samples downloaded in ser io rab20 zip Rabbit 4000 Designer s Handbook rabbit com 77 11 2 3 Diagnostic Test 2 The following program checks the processor RAM interface for an SRAM device connected to CS1 OE
18. by a 2 byte length field the number of bytes in the sec ondary loader The 7th byte is a checksum simple summation of the previous 6 bytes Whether or not the checksum matched it is echoed back as an acknowledgement 7 The data segment is then mapped to the given physical location using the DATASEG register The data segment boundary will also be set to 0x6000 so the secondary loader will always be located at the same place in logical space regardless of where it physically resides 8 The initial loader finally enters a loop where it receives the specified number of bytes that compose the secondary loader program pilot bin sent by the PC and writes those bytes starting at 0x6000 logical The first byte sent this way MUST be OxCC as an indicator to the initial loader This byte will be stored as 0x00 nop instead of OxCC A 2 byte checksum will be sent after the secondary loader has been received using the 8 bit Fletcher Algorithm see RFC1145 for details such that the load can be verified After all of the bytes are received and the checksum has been sent program exe cution jumps to 0x6000 9 The secondary loader does a wrap around test to determine how much RAM is available and reads the flash and CPU IDs This information is made available for transmittal to Dynamic C when requested 10 The secondary loader now enters a finite state machine FSM that is used to implement the Dynamic C Target Communications protocol Dynami
19. cleaning fluids during solder wave and reflow operations The plastic molding compounds used for IC packaging encapsulation is hygroscopic that is it readily absorbs moisture The amount of moisture absorbed by the package is proportional to the storage environment and the amount of time the package is exposed to the humidity in the environment During the solder reflow process the package is heated rap idly and any moisture present in the package will vaporize rapidly generating excessive internal pressures to various interfaces in the package The vapors escaping from the package may cause cracks or delamina tion of the package These cracks can propagate through the package or along the lead frame thus expos ing the die to ionic contaminants and increasing the potential for circuit failures The damage to the package may or may not be visible to the naked eye This condition is common to all plastic surface mount components and is not unique to Rabbit microprocessors Rabbit microprocessors are shipped to customers in moisture barrier bags with enough desiccant to main tain their contents below 20 relative humidity for up to 12 months from the date of seal A reversible Humidity Indicator Card is enclosed to monitor the internal humidity level The loaded bag is then sealed under a partial vacuum The caution label IPC JEDEC J STD 020 LEVEL 3 included with each bag out lines storage handling and bake requirements The requirements out
20. com Rabbit Memory Organization 5 3 Separate I amp D Space Separate instruction and data space is a hardware memory management scheme that uses address line inversion to double the amount of logical address space in the base and data segments In other words this doubles the amount of root code and root data available for an application program Without separate I amp D space recall that in a typical memory map of the 16 bit address space the base seg ment holds a mixture of code and constants and is mapped to flash the data segment holds C variables and is mapped to RAM With separate I amp D space code and data no longer have to divide this space because they share logical addresses by inverting address lines depending on whether the CPU is fetching instruc tions or data The drawing in Figure 5 2 shows the logical address space when separate I amp D space is both enabled and disabled Typical SEGSIZE values are shown The boundary at 0x3000 and 0x6000 is determined by the macro ROOT SIZE 4Xin the BIOS The value of this macro is the number of 4 kilobyte pages used for the base segment The boundary may be changed but care must be taken To change the boundary define ROOT SIZE _ 4X to the desired number of 4K pages on the Defines tab in Options Project Options Figure 5 2 16 Bit Logical Address Space Separate I amp D Space Disabled Separate 1 amp D Space Enabled SEGSIZE D6 1 SEGSIZE D3 OxFFFF XMEM Segment Stack
21. e the logical address space for root data 5 3 3 Customizing Interrupts No special code is required to customize interrupts using separate I amp D space on the Rabbit 4000 with the addition of the RAM segment register RAMSR Use Set Vect Intern and SetVectExtern to set interrupts Please see the Dynamic C Function Reference Manual for more information on these functions 5 4 How The Compiler Compiles to Memory The compiler generates code for root code root constants extended code extended constants and far con stants It allocates space for data variables but except for constants does not generate data to be stored in memory Any initialization of RAM variables must be accomplished by code since the compiler is not present when the program starts in the field Please see GLOBAL INIT inthe Dynamic C User Man ual Static variables are not zeroed out by default The BIOS macro ZERO OUT STATIC DATA may be set to 1 which will only zero out static variables on board power up or reset Zeroing out static variables is not compatible with the use of protected variables because they will be zeroed out along with the rest of the static data 5 4 1 Placement of Code in Memory Code may be placed in either extended memory or root memory Functions execute at the same speed but calls to functions in root memory are slightly more efficient than calls to functions in extended memory In all but the smallest programs most
22. high This causes the Rabbit 4000 to enter the cold boot mode after reset Rabbit 4000 Designer s Handbook rabbit com 13 When the programming cable connects a PC serial port to the target controller board the PC running Dynamic C is connected to the Rabbit 4000 as shown in the table below Table 4 1 Programming Port Connections PC Serial Port Signal Rabbit 4000 Signal DTR output RESET input reset system DSR input STATUS general purpose output TX serial output RXA serial input port A RX serial input TXA serial output port A When Dynamic C cold boots the Rabbit 4000 based target system it assumes that no program is already installed on the target The flash memory on the target system may be blank or it may contain any data The cold boot capability permits the use of soldered in flash memory on the target Soldered in memory eliminates sockets boot blocks and PROM programming devices 4 1 How the Cold Boot Mode Works In Detail Cold boot works by receiving triplets of bytes that consist of a high address byte followed by a low address byte followed by a data byte and writing the data byte to either memory or I O space Cold boot mode is entered by having one or both of the SMODE pins pulled high when the Rabbit is reset The pin settings determine the source of the incoming triplets SMODE 0 SMODEO 1 cold boot from slave port SMODE 1 SMODEO 0 cold boot from clocked serial
23. how memory mapping works on the Rabbit 2000 and 3000 This document is avail able at www rabbit com support techNotes whitePapers shtml 5 1 Physical Memory The Rabbit 4000 has a configurable physical address space The default addressable space on the 4000 is 1 MB the same as that used on the Rabbit 2000 and 3000 However on the Rabbit 4000 the physical address space can be reconfigured to use additional address lines to resize the physical memory from 512 K to 16 MB The physical memory can be increased to 4 MB without the use of additional address lines by mapping in 1 MB memory devices into the four available physical memory banks In special cir cumstances more than 16 MB of memory can be installed and accessed using auxiliary memory mapping schemes Typical Rabbit 4000 systems have two types of directly addressable physical memory flash memory and static RAM 5 1 1 Flash Memory Flash memory in a Rabbit 4000 based system may be small sector or large sector type Small sector mem ory typically has sectors of 128 to 4096 bytes Individual sectors may be separately erased and written In large sector memory the sectors are often 16 KB to 64 KB or more Large sector memory is less expensive and has faster access time The best solution will usually be to lay out a design to accept several different types of flash memory including the flexible small sector memories and the fast large sector memories Flash memory follows a write once in
24. int ramSize int ramSpeed int cpuID long crystalFreq char macAddr 6 char serialNumber 24 char productName 30 74 in nanoseconds 2nd flash Rabbit part in 1000h pages in nanoseconds CPU type ID in Hertz Media Access Control MAC address device serial number NULL terminated string Begin new version 5 System ID block member structure SysIDBlockType2 idBlock2 End new version 5 System ID block member structure char reserved 1 long idBlockSize unsigned userBlockSize unsigned userBlockLoc int idBlockCRC char marker 6 SysIDBlock idblock reserved for later use size can grow number of bytes in the SysIDBlock struct User block size in bytes right below ID block offset in bytes of start of User block from this one CRC of this block when this field is set to 0 should be 0x55 OxAA 0x55 OXAA 0x55 OxAA Rabbit 4000 Designer s Handbook rabbit com 53 7 1 2 Reading the System ID Block To read the ID block from the flash instead of getting the information from SysIDBlock call _readIDBlock _readIDBlock int readIDBlock int flash bitmap DESCRIPTION Attempts to read the system ID block from the highest flash quadrant and save it in the system ID block structure It performs a CRC check on the block to verify that the block is valid If an error occurs SySIDBlock tableVe
25. of the code is compiled to extended memory Root constants share the memory space needed for root code when separate I amp D space is disabled so as the memory needed for root constants increases the amount of code that can be stored in root memory decreases and code must be moved to extended memory Please see the Dynamic C User Manual regarding the compiler directive memmap for more informa tion about controlling the placement of code in memory 5 4 2 Paged Access in Extended Memory The code in extended memory executes in the 8 KB window from 0xE000 to OxFFFF This 8 KB window uses paged access Instructions that use 16 bit addressing can jump within the page and also outside of the page to the remainder of the 64 KB logical space Special instructions particularly LCALL LJP and LRET are used to access code outside of the 8 KB window for addresses below 0x100000 Similarly LLCALL LLJP and LLRET can be used to access code outside of the 8KB window to any place in the physical address space When one of these transfer of control instructions is executed both the address and the view through the 8 KB window change allowing transfer to any instruction in the physical mem ory space The 12 bit LXPC register controls which of two consecutive 4 KB pages the 8 KB window aligns with there are 256 pages in a 1 MB physical address space The 16 bit PC controls the address of the instruction usually in the region 0xE000 to OxFFFF The advantag
26. port A SMODE 1 SMODEO 1 cold boot from asynchronous serial port A at 2400 bps SMODE 0 SMODEO 0 start normal execution at address zero The SMODE pins can be used as general input pins once the cold boot is complete On entering cold boot mode the microprocessor starts executing a 12 byte program contained in an inter nal ROM The program contains the following code origin zero 00 ld 1 n n 0c0h for serial port A n 020h for parallel slave port 02 ioi ld d h1 get address most significant byte 04 ioi ld e hl get least significant byte 06 ioi 1d a h1 get data 08 ioi or nop if the high bit of the MSB of the address is 1 i e d 7 1 then ioi else nop 09 ld de A store in memory or I O 10 jr 0 jump back to zero note wait states inserted at bytes 3 5 and 7 waiting for serial port or parallel port ready 14 rabbit com How Dynamic C Cold Boots the Target System The function of the boot ROM program depends on the settings of the pins SMODEO and SMODE 1 and on whether the high bit of the high address byte first byte of a received triplet that is loaded to register D is set If bit 7 of the high address byte is set then the data byte last byte of the triplet is written to I O space when received If the bit is clear then the data byte gets written to memory Boot mode is terminated by storing 80h to I O register 24h which causes an instruction fetch to begin at address zero Wai
27. relative to the beginning or end of its parent or a sibling and this placement determines its orientation The orientation determines how other siblings may reference the origin for example if a child is placed at the end of a parent origin no sibling origins may be declared above it lt vector gt The non terminal vector consists of the terminal above or the terminal below followed by an the non terminal offset The declaration determines the meaning of offset above indicates that the offset will be the lower boundary of the declared origin while below indicates that the offset will be the upper boundary lt offset gt The non terminal offset is either the non terminal position or the non terminal name A name must be the identifier of a previously declared sibling origin When placing an origin above a sibling the upper boundary of the reference origin is used as the lower boundary of the origin being declared Simi larly when placing an origin below a sibling the lower boundary of the reference origin is used as the upper boundary of the origin being declared lt position gt A position can be either of the special terminals start or end or it can be a physical offset followed by an optional logical address Though inessential to the grammar the terminal symbols phy and log pre vent accidental macro expansion problems and add clarity fo
28. set to one For more information on cloning please see Chapter 8 BIOS Support for Program Cloning in this manual and or Technical Note 207 Rabbit Cloning Board available at rabbit com Rabbit 4000 Designer s Handbook rabbit com 35 FLASH SIZE Sets the amount of flash available The default value is the internally defined FLASH SIZE The units are the number of 4 KB pages of flash In special situations such as splitting flash between two coresident programs this may be modified to a smaller value than the actual available flash RAM SIZE Sets the amount of RAM available The default value is the internally defined RAM SIZE_ The units are the number of 4 KB pages of RAM In special situations such as splitting RAM between two coresi dent programs this may be modified to a smaller value than the actual available RAM USE TIMERA PRESCALE Uncomment this macro in Lib Rabbit4000 BIOSLIB sysconfig c to run the peripheral clock at the same frequency as the CPU clock instead of the standard CPU clock 2 This allows higher baud rates if Timer A is used as the baud rate generator JSE TIMERA PRESCALE affects the resolution of the PWM Input Capture and Quadrature Decoder systems USE 2NDFLASH CODE Uncomment this macro in Lib Rabbit4000 BIOSLIB sysconfig c only if you have aa board with two flash devices and you want to use the second flash for extra code space WATCHCODESIZE This macro defines the size in bytes of th
29. the end of its parent rootdata with size WATCHCODESIZE This information is used to determine the starting logical address We know that the starting logical address of the parent rootdata is ROOTCODE_SIZE The logical addresses for child origins necessarily must be relative to their parents In this case that means that the starting logical address for watcode is then ROOTCODE_SIZE ROOTDATA_SIZE WATCHCODESIZE orgdef xvarorg xmemdata in ram above rootdata to userdata buff The origin named xmemdata is a child of ram and as such inherits the property of being battery backed The origin starts where its sibling origin rootdata ends therefore it starts at ORG_RAM_START ROOTDATA_SIZE xmemdata extends to the beginning of userdata_buff The declaration for the origin named userdata_buff is in memory_layout lib along with the declarations for Rabbit 4000 Designer s Handbook rabbit com 39 several other regions needed for buffers For simplicity s sake none of them are shown here and they are not reflected in Figure 6 2 Figure 6 2 Origins from memory_layout lib Logical Space Physical Space Parent Origins Child Origins Child Origins nest level 1 nest level 2 ORG RAM SIZE Xmem Data xmemdata ORG_RAM_START ROOTDATA SIZE ORG RAM START ROOTDATA SIZE WATCHCODESIZE Root Data rootdata ORG RAM START Root Data Root Code ORG FLASH SIZE
30. the last completed update transaction In addition to making data more secure this redundancy allows even very large sector flash types to be used without requiring a large RAM buffer to temporarily store the contents of a sector since sectors must be erased before they can be written In Dynamic C 7 20 and later the possibility of mirrored combined ID User blocks requires that multiple locations in flash must be checked for a valid ID block In versions 7 20 through 7 3x the sequence described above in Section 7 1 2 1 is used to check not only the top of the primary flash but also 8KB 16KB and 24KB below the top and an error is returned only if no valid ID block is found at any of these locations Note the implication here that mirrored combined ID User blocks are limited to one of 8KB 16KB or 24KB in size Dynamic C versions 8 and later check more locations in flash from the top down at each lower 4KB boundary to 64KB below the top This allows Dynamic C 8 and up to recognize a com bined ID User blocks size that is any multiple of 4KB up to a maximum of 64KB If the version of the System ID block doesn t support the User block or no System ID block is present then the 8 KB starting 16 KB from the top of the primary flash are designated the User block area How ever to prevent errors arising from incompatible large sector configurations this will only work if the flash type is small sector Rabbit manufactured boards with large sector flas
31. to many types of external I O peripher als The processor provides a common I O read and I O write strobe in addition to eight user configurable T O strobes that can be used as read write read write or chip select signals The Rabbit 4000 also provides the option of enabling a completely separate bus for I O accesses The Auxiliary I O Bus which uses many of the same pins used by Parallel Port A and the Slave Port provides 8 data lines and 6 to 8 address lines that are active only during I O operations By connecting I O devices to the auxiliary bus the fast memory bus is relieved of capacitive loading that would otherwise slow down memory accesses For core modules based on the Rabbit 4000 fewer pins are required to exit the core module since the slave port and the I O bus can share the same pins and the memory bus no longer needs to exit the module to provide I O capabil ity As far as external I O timing is concerned the Rabbit 4000 provides e half a clock cycle of address and chip select hold time for I O write operations and e zero clock cycles of address and chip select hold times for I O read operations These can both be increased to a full clock of hold time These hold times are true if an I O device is inter faced to the common memory and I O bus However if an I O peripheral is interfaced to the Auxiliary I O bus address hold time is no longer an issue as the address does not change until the next external I O oper ation
32. two flash memory chips If you are writing a program from scratch remember that 1 MB of code is equivalent to 50 000 to 100 000 C statements and such a large program can take years to write If you are using Dynamic C libraries it is fairly easy to have this much code in your appli cation Constant data tables can be conveniently placed in extended memory using the xdata and xstring declarations supported by Dynamic C so the amount of space needed for constant data can be added to the amount of space needed for code The far keyword can also be used to create constants in xmem using stan dard C variables 5 5 2 Static RAM C programs vary in how much RAM will be required and having more RAM is necessary for debugging Since debugging and program testing generally operate more powerfully and faster when sufficient RAM is available to hold the program and data most controllers based on the Rabbit 4000 use a dual footprint for RAM that can accommodate either a 32K x 8 which is in a 28 pin package or a 128K x 8 or 512K x 8 which is in a 32 pin package The base RAM is interfaced to CS1 and WE1 and OE1 RAM is required for the following items e Root Variables maximum of 40 44 KB and about 4 KB more if separate I amp D space is enabled e Stack Pages stack is usually 4 KB rarely more than 20 KB e Debugging as a convenience on prototype units 1 MB is usually enough to accommodate programs It is not necessary to debug in RAM but
33. value will only increase available xmem code space not root code space which is generally in shorter supply To increase available xmem code space the following general procedure should be followed 1 Determine that binary forward compatibility with large sector flash types as described above is not an issue This means that the application will only ever run on target boards equipped with small sector flash i e uniform sectors of a size no larger than 4 KB 2 Determine the application s minimum User block size requirement If the application does not write to the User block this size is zero 3 If the target board has factory calibration constants stored in the User block add the size reserved for these constants Consult your hardware manual for the reserved size required Add the size of the System ID block which is 132 bytes for versions 2 through 4 Round this total size up to the next higher 4 KB block boundary If using mirrored combined version 3 or 4 ID User blocks double the size Calculate the number of 4 KB blocks required for the total size Edit the write idblock c utility to set the required number of 4 KB blocks and write a new ID block onto the target board 9 Repeat the previous steps for every board which is to be programmed with the application s compiled using the updated MAX USERBLOCK SIZE macro value 10 Edit the RabbitBios c file to update the MAX USERBLOCK SIZE macro value 58 rabbit c
34. voltage alone leakage current and dependent on both voltage and frequency switching and crossover current Table 2 1 shows typical current draw as a function of the main clock frequency The values shown do not include any current consumed by external oscillators or memory It is assumed that approximately 30 pF is connected to each address line NOTE VDDCORE 1 8 V 10 VDDIO 3 3 V 10 TA 40 C to 85 C Table 2 1 Preliminary Current vs Clock Frequency Frequency MHz core mA 1 10 mA _ Total mA 7 3728 4 10 14 14 7456 6 11 17 29 4912 10 12 22 58 9824 18 15 33 Rabbit 4000 Designer s Handbook rabbit com 5 2 4 Through Hole Technology Most design advice given for the Rabbit 4000 assumes the use of surface mount technology However it is possible to use the older through hole technology and develop a Rabbit 4000 system One can use a Rabbit 4000 based Core Module a small circuit board with a complete Rabbit 4000 core that includes memory and oscillators Another possibility is to solder the Rabbit 4000 processors by hand to the circuit board This is not difficult and is satisfactory for low production volumes if the right technique is used 2 5 Moisture Sensitivity Surface mount processing of plastic packaged components such as Rabbit microprocessors typically involves subjecting the package body to high temperatures and various chemicals such as solder fluxes and
35. 1 WE1 The test toggles the first 16 address lines All of the data lines must be connected to the SRAM and functioning or the program will not execute correctly A series of triplets are sent to the Rabbit via one of the bootstrap ports to set up the necessary control regis ters and write several instructions to RAM Finally the bootstrap termination code is sent and the program begins executing instructions in RAM starting at address 0x00 The following steps illustrate one way to create a diagnostic program 1 Write a test program in assembly main asm boot ld hl 1 ld b 16 loop ld a hl add hl hl shift left djnz loop 16 steps jp 0 continue test endasm 2 Compile the program using Dynamic C and open the Assembly window The disassembled code looks like this T2 Dynamic C Dist 7 30P File Edit Compile Run Inspect Options Window Help Edit Compile Disassembled Code laf A 1c46 0610 ld b 10 1c48 7E ld a hl 1c49 29 add hl hl ic4a 10FC djnz 1 48 liede c30000 jp AF aA miz 78 rabbit com Troubleshooting Tips for New Rabbit Based Systems 3 The opcodes and their data are in the 2nd column of the Assembly window Since we want each triplet loaded to RAM beginning at address zero create the following sequence of triplets code to be loaded in SRAM 00 00 21 00 01 01 00 02 00 00 03 06 00 04 10 00 05 7E 00 06 29 00 07 10 00 08 FC 00 09 C3 00 OA 00 00 OB 00 4
36. 11 0592 MHz 14 7456 MHz 22 1184 MHz 29 4912 MHz or double these frequencies NOTE The internal clock doubler can double these oscillations for a higher operating fre quency e Digital VO line PB1 should not be used in the design if cloning is to be used PB1 should be pulled up with 50K or so pull up resistor if cloning is used See BIOS Support for Program Cloning on page 63 for more information on cloning Rabbit 4000 Designer s Handbook rabbit com 3 2 1 1 Rabbit Programming Connector The user may be concerned that the requirement for a programming connector places added cost overhead on the design The overhead is very small less than 0 25 for components and board space that could be eliminated if the programming connector were not made a part of the system The programming connector can also be used for a variety of other purposes including user applications A device attached to the programming connector has complete control over the system because it can per form a hardware reset and load new software If this degree of control is not desired for a particular situa tion then certain pins can be left unconnected in the connecting cable limiting the functionality of the connector to serial communications Rabbit develops products and software that assume the presence of the programming connector 2 1 2 Memory Chips Most systems have one static RAM chip and one or two flash memory chips but more memory chips can
37. 3 2 2 Compiling to Flash For flash compiles flash is mapped to banks 0 and 1 The address range depends on the size of the physi cal address space For example a 20 bit address space with 512 KB of flash would mean that flash is mapped from 0x00000 to Ox7FFFF Alternatively a 22 bit address space 1 MB quadrants with 1 MB of flash would mean that the flash is mapped to 0x000000 to OxXOFFFFF in bank 0 and is repeated again in bank 1 from 0x100000 to 0x1FFFFF RAM is mapped to banks 2 and 3 address range 0x80000 to OxFFFFF for 20 bit and 0x200000 to Ox3FFFFF for 20 bit respectively Register Settings Figure 5 5 Flash Compile Memory Mapping MECR 0x0 MMIDR 0x29 SEGSIZE 0xD3 DATASEG 0x0 0x3000 0x0000 Shared OxFFFF 0xE000 0xD000 Root Data Constants Root Code Root Code Xmem Stack 0x8DOOO 0x83000 0x80000 0x13000 0x10000 0x0D000 0x03000 0x00000 Stacks xalloc etc Root Data Stack Space Watch Code Xmem Code continued Root Constants Xmem Code Root Code Root Code The BIOS sets the MMIDR to 0x29 to enable the I amp D space for flash compilation Bit 5 of this register enables the I amp D split bit 0 enables inversion of A16 for the data space base segment 1 e the logical Rabbit 4000 Designer s Handbook rabbit com 27 address space for constants and bit 3 enables inversion of MSB for the data space data segment i
38. 6 SEG Ee ED Re hg cece Se Ee Rede ee Es eee en ee ee ee 17 RR SET US n AE NE EE HE ARE AREA EE N EE RE EEEE 17 DD SRAM AE EE AE EE A 18 5 1 3 Basic Memory Configuration sesse seek see ee ke GR ek GR Ge GR AA Ge ee ee ee GR ee Re Ge GR ek GR Ge ee ee 18 muse ui N RE ER EE OE N OR EE 19 52 1 Defi ton of Terms issie aaien ene ee vee esse dere oe eo aE e EEE rE E S i eai NEE Ie 20 5 2 2 The Base of Root Segmerit sie ss EE RE Eg Ee eke Ee RR Gee EER iiaa E Ad Ge See Re gee Ge eke 21 5 2 2 1 Types of Code Best Suited for the Base Segment see ee Re Re Re Re ee 21 5 2 3 The Data Sement sonsir EE ER rende ee ese a ede ee ee eek eed eed ee 21 5 2 4 The SE Ty do died RE GE EE RO EE GE EN 21 5 2 5 The Extended Memory Segment ees sesse se ee ee Re Re Re ee Re ee ee Re ee Ge ee ee GR ee veer Re Re Re Re ee 22 Separate Pd DES AE EE EN ARE HEG 23 Rabbit 4000 Designer s Handbook rabbit com iii 5 3 1 Enabl Separate 1 amp D Space susse sesse EE SEE SE se SARA GE EG See Se RA Se Ee E Roe DEd Eed ese Se ee ese geag see 25 5 3 2 Separate I amp D Space Mappings in Dynamic CC sesse ses ee Re ee Re ee Re Re Re RA ee ee ee ee 25 5 3 2 1 Compiling to RAM OER OE EE RE EN 26 53 22 Compiling t EL RE ss sonestedexdsa Erra Eneo E E E E E NEE N EEES Ekes 27 3 33 Customizing Interrupts sinesine eeii NR E E E E GEREGEER ESE a N TEE 28 5 4 How The Compiler Compiles to Memory ccccccscesseeseeseeeseeseceseeseeeeecseceseeaeensesseeae
39. 6 KB pages on the actual memory device These would be used for special compila tions of programs to be coresident on flashes between 512 KB and 1 MB in size For more information please see Technical Note 202 Rabbit Memory Management In a Nutshell RAMONLYBIOS Default value is 0 Set to 1 if you are developing with a board with RAM on CS0 WEO OEO and no flash Please see Section 5 6 Making a RAM Only Board for details 6 5 Memory Mapping in Dynamic C The Dynamic C compiler uses the information provided by origin directives to decide where to place code and data in both logical and physical memory The term origin is the mechanism by which a memory region is initially described Dynamic C version 10 21 introduces a greatly improved version of the origin directives The newer version of origin directives is described in Section 6 5 1 and the older version is described in Section 6 5 2 Origin directives allow the programmer to tell the compiler where devices should be mapped in the Rabbit processor memory space The origins are further used to describe what each device is and what properties these devices may have Although origins are normally defined in the BIOS or one of its configuration libraries they may also be useful in an application program for certain tasks such as compiling a pilot BIOS or a cold loader or special situations where a user wants two applications coresident within a single 256K quadrant of flash S
40. EE EE OE EE OE SaaS 78 Appendix A Supported Rabbit 4000 Baud Rates ees se ee RA Re ee ee RA ee Re ee ee 81 Vee en ER ER RA OE EE 83 Rabbit 4000 Designer s Handbook rabbit com v vi rabbit com Table of Contents Semiconductor 1 Introduction This manual is intended for the engineer designing a system using the Rabbit 4000 microprocessor and Rabbit s Dynamic C development environment It explains how to develop a system that is based on the Rabbit 4000 and can be programmed with Dynamic C With Rabbit 4000 microprocessors and Dynamic C many traditional tools and concepts are obsolete Complicated and fragile in circuit emulators are unnecessary EPROM burners are not needed Rabbit 4000 microprocessors and Dynamic C work together without elaborate hardware aids provided that the designer observes certain design conventions For all topics covered in this manual further information is available in the Rabbit 4000 Microprocessor User 5 Manual 1 1 Summary of Design Conventions e Include a programming connector e Connect a static RAM having at least 128 KB to the Rabbit 4000 using CS1 OE1 and WE1 e Connect a flash memory that is on the approved list and has at least 128 KB of storage to the Rabbit 4000 using CSO OEO and WEO e Install a crystal oscillator with a frequency of 32 768 kHz to drive the battery backable clock Battery backing is optional but the clock is used in the cold boot sequence
41. EE OE 36 6 5 Memory Mapping in Dynamic Cu ss sesse se ske se sk GR Ge GR EA Ge ee ee ee ee GR GR Re GR GR Ge ee ee de ee ee 37 6 5 1 Origins Starting with Dynamic C 10 21 ee RR RA Re RA ee Re ee Re Re Re RA Re Re Re 37 6 5 1 1 Example of Origin Declarations iese see ee ee ee Re GRA Re ee RA Re ee Re ee Re ee ee eg 38 6 5 1 2 Origin Declaration Syntax ie Ge N GERGEN EE raie pis SR GR ee EE Ke AR DR sg ee IEE eed eN RR es 41 6 5 1 3 Origin Declaration Semantics ese RR Ge Re RA Re RA Re AR ee Re ee Re ee Re ee 41 6 5 1 4 Origin Declaration Start and End Syntax cccccccccecessecsceeseeeeeeseceseeseeeeeeseeneeseseeeeasenaes 44 6 5 1 5 Origin Application Syntax ees eke Re RR Ge Re Re Re RA ee RA Re ee Re Re Re ee ae eg 44 6 5 1 6 Origin Macro Declaration Syntax cccccccceccescessesssceseeecseeeseeceeseceseesecesesseceeeeeseeeeaeenaes 44 6 5 2 Origins Prior to Dynamic C 10 21 ee ae RA Re Re RA Re Re ee Re ee ririri s Re Re ee Re ee 45 6 5 2 1 Origin Directive Semantics ccccceceescesceesecsceesececeeseceseeseceeeeseceeesseseeeseseeseaeeneseaeeneeeaes 45 6 5 2 2 Defining a Memory Region cccceceesseeseesseeseesceeseceecesecseenseceesaeecaeeaeeesesseeeaeseeenaeeasenaes 46 6 5 2 3 Action Qualifiers cccccccccccccsseessccsssccsseceseceseeessecsseecsesceseceseccsseceseecescesseesseesseseeeeesessaes 46 6 52 4 TED Qual Meis RE Riess casks ER EE EE Ee eves ee WU a tase na EE Ee es ed 46 6 5 2 5 Follow Qualifier
42. For more information on I O timing please refer to the Rabbit 4000 Microprocessor User s Manual Some I O peripherals such as LCD controllers and Compact Flash devices require address and chip select hold times for both read and write operations If the peripheral is interfaced to the Auxiliary I O bus address hold time is not an issue If chip select hold time is required an unused auxiliary I O address line can be used to generate the chip select In situations where I O peripherals are interfaced to the common memory and I O bus address and chip select hold times can be extended under software control or with minor hardware changes Please refer to Technical Note 227 Interfacing External I O with Rabbit 2000 3000 Designs for additional information This document is available online at www rabbit com docs app tech notes shtml 10 rabbit com Core Design and Components 3 4 PC Board Layout and Memory Line Permutation To use the PC board real estate efficiently it is recommended that the address and data lines to memory be permuted to minimize the use of PC board resources By permuting the lines the need to have lines cross over each other on the PC board is reduced saving feed through s and space For static RAM address and data lines can be permuted freely meaning that the address lines from the processor can be connected in any order to the address lines of the RAM and the same applies for the data lines For example if the RA
43. M S 1 ODh 4 Flash ID 2 11h 2 Flash size in 1000h pages 2 13h 2 Flash sector size in bytes 2 15h 2 Number of sectors in flash 2 17h 2 Flash access time nanoseconds 4 19h 4 Flash ID 2nd flash 2 1Dh 2 Flash size in 1000h pages 2nd flash 2 1Fh 2 Flash sector size 2nd flash in bytes 2 Rabbit 4000 Designer s Handbook rabbit com 55 Table 7 1 The System ID Block Continued Offset from start of Size Description Filled as Required bytes of Version block 21h 2 Number of sectors in 2nd flash 2 23h 2 Flash access time in nanoseconds for the 2nd 4 flash 25h 4 RAM ID 2 29h 2 RAM size in 1000h pages 2 2Bh 2 RAM access time in nanoseconds 4 2Dh 2 CPU ID 3 2Fh 4 Crystal frequency Hertz 2 33h 6 Media Access Control MAC address 1 x 39h 24 Serial number as a null terminated string 51h 30 Product name as a null terminated string Version 5 System ID block member structure ai 27 SysIDBlockType2 a 8Ah N Reserved variable size SIZE 4 Size of System ID block in bytes 1 x 10h SIZE E OCh 2 Size of User block in bytes 1 x SIZE 2 Offset in bytes of User block location from start l OAh of this block j SIZE 2 CRC value of System ID block when this field l x 08h 0000h SIZE 06h 6 Marker should 55h AAh 55h AAh 55h AAh 1 X 56 rabbit com The System Identification and User Blocks 7 1 3 Writing the Sys
44. M has 15 address lines and 8 data lines it makes no difference if A15 from the processor connects to A8 on the RAM and vice versa Similarly D8 on the processor could connect to D3 on the RAM The only restriction is that all 8 processor data lines must connect to the 8 RAM data lines If several different types of RAM can be accommodated in the same PC board footprint then the upper address lines that are unused if a smaller RAM is installed must be kept in order For example if the same footprint can accept either a 128K x 8 RAM with 17 address lines or a 512K x 8 RAM with 19 address lines then address lines A18 and A19 can be interchanged with each other but not exchanged with A0 A17 Permuting lines does make a difference with flash memory and must be avoided in practical systems 3 5 PC Board Layout and Electromagnetic Interference Most design failures are related to the layout of the PC board A good layout results when the effects of electromagnetic interference EMI are considered For detailed information regarding this subject please see Technical Note 221 PC Board Layout Suggestion for the Rabbit 3000 Microprocessor This docu ment is available at www rabbit com docs app_tech_notes shtml 3 5 1 Rabbit 4000 Low EMI Features The Rabbit 4000 has powerful built in features to minimize EMI They are noted here For details please see The Rabbit 4000 Microprocessor User Manual e Separate power pins exist for core and I O rin
45. R GR GR Ge RA Ge ge AA ee ee ke 70 9 9 2 Sleepy Mode us ie a EE Ee EE ee ee ee E Re GE Ee 70 9 2 3 External 32 kHz Oscillator esse sees see se ke Re Re Re Re Re ee Re ee ee ee GR ee Re Re ee RA Re Re ee ee ee ee 71 9 2 4 Conformal Coating of 32 768 kHz Oscillator Circuit sesse see see se Ge ee ge ee ee ee ek GR Ge ke ee 71 9 2 5 Software Support for Sleepy Mode see ee RR Ge Re Re ee Re GR ee Re Re ee RA Re RA ee ee ee ee 71 9 2 6 Baud Rates in Sleepy Mode isi ese Le RE og De VER Seg ER Ge KG SRSA Ge DERS SS D NSR EN Ge R GN Ee n dd E ieke 72 9 2 7 Debugging in Sleepy Mode ee Re Re Re Re Re ee Re ee ee Re ee GR ee Re Re Re Re Re Re ee ee 72 Chapter 10 Supported Flash Memories sees sesse ese se Ag ee Ge AG AE ge AA AG ee AE ge 73 10 1 Supporting Other Flash Devices esse sesse see AA RA Ee ee SA Ge de AA Ee de Se ee ee ee AA Ge ed eg 73 10 2 Writing Your Own Flash DYiVer esse sesse ese ee ese ee ee ee Ge GR GR GR GR Re Ge Ge Ge ee ee Re ee Re Re ke GR Ge Re Ge Ge ee 73 Chapter 11 Troubleshooting Tips for New Rabbit Based Systems iese se se ee ee AR 75 MAA in EIE Se Sn ara EE EO E EE EG 75 11 2 DER oi AA RE RE EO suse AE 75 11 2 1 Program to Transmit Diagnostic Test ea RA Re Re ee Re ee Re Re Re Re Re Re Re Re Re 75 11 2 2 Diagnostic Test 1 Toggle the Status PIN cece sesse see se ee GR GR GR Ge AR Ge Ge ee AA Re ee ek Re ke 71 112 2 Usine sena OR EE EE ER EE OE N 77 11 2 3 Diagnostic Test RR EE EE RE
46. Segment OXDOOO Common Space OxFFFF XMEM OXDOOO Instruction Space Data Space OxCFFF 0x3000 Base Segment Base Segment Root Code Constants Base Segment 0x0000 NOTE This diagram illustrates how separate I amp D space works the actual values used in the BIOS may differ from those shown here I I I I I I I I I I I I I I I i Data Segment Data Segment Data Segment i Root Code Root Data i 0x6000 I I I I I I I I I I I I 0x0000 Rabbit 4000 Designer s Handbook rabbit com 23 Separate I amp D logical addresses map to physical addresses by inverting address lines A16 the most signifi cant address bit or both The most significant address bit may be A18 A23 depending on the MECR set ting The MMU Instruction Data Register MMIDR determines which lines are inverted Please see the Rabbit 4000 Microprocessor User s Manual for more information about the MMIDR The following diagram Figure 5 3 shows the physical address space when separate I amp D space is enabled SEGSIZE 0xD3 and code is compiled to flash The inversion of A16 causes the root constants in the data space to be addressed in the second 64 KB block of the flash The inversion of MSB A19 in this example causes the root data in the data space to be located in RAM RAM is mapped at 0x80000 starting at 0x83000 as directed by the lower nibble of SEGSIZE Figure 5 3 Physical Address Space when Separate I
47. The code to be loaded in SRAM must be flanked by triplets to configure internal peripherals and a trip let to exit the cold boot upon completion 80 14 05 MBOCR Map SRAM on CS1 OE1 WE1 to Bank 0 80 09 51 ready watchdog for disable 80 09 54 disable watchdog timer code to be loaded in SRAM goes here 80 24 80 Terminate boot strap start executing code at address zero The program serialIO exe has the ability to automatically increment the address Instead of typing in all the addresses you can use some special comments They are case sensitive and must be at the begin ning of the line with no space between the semicolon and the first letter of the special comment Address nnnn Triplet The first special comment tells the program to start at address nnnn and increment the address for each transmitted data byte The second special comment disables the automatic address mode and directs the program to send exactly what is in the file The triplets shown in 3 may be rewritten as Address 0000 21 01 00 ld hl 1 06 10 71d b 16 7E 1d a hl 29 add hl hl 10 FC djnz loop C3 00 00 jjp 0 Triplet Rabbit 4000 Designer s Handbook rabbit com 79 80 rabbit com Troubleshooting Tips for New Rabbit Based Systems Semiconductor Appendix A Supported Rabbit 4000 Baud Rates This table contains divisors to put into TATXR registers All frequencies that allow 57600 baud up to 30MHz are shown as well as a fe
48. _SIZE 38 rabbit com The Rabbit BIOS orgdef xcodorg xmemcode in flash above start to user block Defining origins for the physical memory devices in a particular configuration is not enough for the com piler so we need to define regions for code and data The line above defines an origin for xmem code with xcodorg origin type and called xmemcode The compiler knows to use this origin for xmem code because of the origin type Note that xmemcode is a child of the origin flash so it not only has the prop erty of being a code region but it is also non volatile since it inherits that property from its parent flash The final bit of syntax above start to user_block means that the origin region starts at the beginning of its parent and extends to the beginning of the sibling user block origin region The to syntax allows the origin definition to remain unchanged even if the parent origin changes A to terminal in an origin definition can also be followed by the syntax end to indicate that the region should occupy the entire parent origin region this is useful for organizational purposes orgdef rcodorg rootcode in xmemcode above start log 0 size ROOTCODE SIZE The xmem code origin is defined above to take up the entire flash device other than the small space reserved for the user block The reason for this is that we want to be able to put xmem code anywhere in the flash device However
49. ace a macdef prudence dictates the placing them after orgend is the logical choice in most cases lt define gt The define non terminal represents the assignment of an origin attribute to a specific macro name The non terminal name must be a valid C macro identifier not previously declared The orgval non terminal represents an origin attribute as explained below lt orgval gt An orgval is the non terminal name which must be a previously declared origin followed by an optional non negative integer followed by the optional terminal boundary followed finally by the aspect non ter minal The optional integer specifies an origin fragment if the given origin is fragmented otherwise the compiler ignores it A user must access fragments of an origin linearly as if they were elements of a C array Thus one accesses the first fragment through index zero and so forth The optional terminal boundary signals the compiler to return attributes that the origin had before it were fragmented or short ened by the declaration of any child origins 44 rabbit com The Rabbit BIOS lt aspect gt The aspect non terminal represents an individual aspect of an origin This non terminal may be one of three things It may be the size terminal in which case the compiler assigns the size of the origin in bytes to the macro It may be the fragments terminal wherein the compiler will assign the number of frag ments within the origin to the macro Last
50. ace is enabled Root Memory Logical addresses below 0xE000 Please note that root memory is not the same as the root segment The root segment is contained in root memory as are the data and stack segments The root seg ment is also known as the base segment Root Variables C variables including structures and arrays that are not initialized to a fixed value are located in the data segment 20 rabbit com Rabbit Memory Organization 5 2 2 The Base or Root Segment The base segment has a typical size of 24 KB The larger the base segment the smaller the data segment and vice versa Base segment address zero is always mapped to physical address zero Sometimes the base segment is mapped to flash memory since root code and root constants do not change except when the sys tem is reprogrammed It may be mapped to RAM for debugging or to take advantage of the faster access time offered by RAM Serial flash boot configurations always map the base segment to RAM since there is no parallel flash With separate I amp D space disabled the base segment holds a mixture of code and constants C functions or assembly language programs that are compiled to the base segment are interspersed with data constants Data constants are inserted between blocks of code Data constants defined inside a C function are placed after the end of the code belonging to the function Data constants defined outside of C functions are placed in memory where they are enco
51. amp D Space is Enabled and the Quadrant Size is 256 KB 512K RAM OxFFFFF OxC0000 Ox8D000 Invert 44K 0x83000 A19 0x80000 512K Flash EET 0x13000 Invert 8K A16 OX10000 0x0D000 52K Root Code 0x00000 24 rabbit com Rabbit Memory Organization When using separate I amp D space you can not reference code as data or data as code in logical memory below the stack When using separate I amp D space the processor makes a distinction between fetching an instruction from memory and fetching data from memory The RAM segment register determines the win dow in RAM where root code may be executed Embedded applications that do not need more code or data space do not require any changes for separate I amp D space By default Dynamic C compiles without separate I amp D space enabled 5 3 1 Enable Separate l amp D Space To use separate I amp D space check the enable separate I amp D space option on the Compiler tab of the Options Project Options dialog The Dynamic C command line compiler equivalent is id enable I amp D space and id disable I amp D space Please see the Dynamic C User Manual for more informa tion about the command line compiler The BIOS and the compiler handle the memory mappings so the user does not need to know the details However if you want to change the way an interrupt vector is handled or you need to write a flash driver the rest of this chapter provides you with the necessary information 5 3 2 Separat
52. arger RAM for it to be possible to compile and run Dynamic C programs If the user uses a flash memory from the list of flash memories that are already supported by the BIOS the task will be simpli fied A list of supported flash devices is listed in Technical Note 226 available online at rabbit com docs app_tech_notes shtml If the flash device is not already supported the user will have to write a driver to perform the write opera tion on the flash memory This is not difficult provided that a system with 128 KB of RAM and the flash memory to be used are available for testing An existing BIOS can be used as a skeleton to create a new BIOS Frequently it will only be necessary to change define statements at the beginning of the file In this case it is unnecessary for the designer to understand or work out the details of the memory setup and other processor initialization tasks Refer to the Dynamic C User Manual for details on creating a user defined BIOS Rabbit 4000 Designer s Handbook rabbit com 31 6 1 Startup Conditions Set by the BIOS The BIOS performs initialization tasks and use s library files that contain setup information 6 1 1 Registers Initialized in the BIOS The BIOS sets up initial values for the following registers by means of code and declarations MBxCR There are four memory bank control registers MBOCR MB1CR MB2CR and MB3CR They are 8 bit regis ters each one associated with a quadrant of the phy
53. bbit BIOS 6 5 2 5 Follow Qualifiers The option follow qualifier is best described with an example First let us declare yourcode in an origin statement containing an origin declaration A follow gualifier can only name a region that has already been declared in an origin declaration xcodorg yourcode 0x0 0x5000 0x500 then the origin statement xcodorg mycode 0x0 0x5500 0x500 follows yourcode tells the compiler to activate mycode when yourcode is full This action does an implicit resume on the memory region identified by yourcode In this example the implicit resume also generates a jump to mycode when yourcode is full For data regions the data that would overflow the region is moved to the region that follows Combined data and code regions like rcodorg use both methods which one is used depends on whether code or data caused the region to overflow In our example if data caused yourcode to overflow the data would be written to the memory region identified by mycode Rabbit 4000 Designer s Handbook rabbit com 47 6 5 2 6 Origin Directive Examples The diagram below shows how the origin directives define the mapping between the logical and physical address spaces define DATASEGVAL 0x91 rvarorg rootdata DATASEGVAL OxC5FF 0x6600 apply grows down rcodorg rootcode 0x00 0x0000 0x6000 apply wcodorg watcode DATASEGVAL OxC6 00 0x0400 apply xcodorg xmemcode OxF8 OXEOOO Ox1A000 apply data declarations start here
54. be used when appropriate Static RAM chips are available in 128K x 8 256K x 8 and 512K x 8 sizes They are all available in 3 V versions Suggested flash memory chips between 128K x 8 and 512K x 8 are given in Chapter 10 Supported Flash Memories That chapter also includes instructions for writing your own flash driver The list of supported flash memories is in Technical Note 226 Supported Flash Memo ries Dynamic C and a PC are not necessary for the production programming of flash memory since the flash memory can be copied from one controller to another by cloning This is done by connecting the system to be programmed to the same type of system that is already programmed This connection is made with the Rabbit Cloning Board The cloning board connects to the programming ports of both systems A push of a button starts the transfer of the program and an LED displays the progress of the transfer Please visit www rabbit com store index shtml to purchase the Rabbit Cloning Board 2 1 3 Oscillator Crystals Generally a system will have two oscillator crystals e A 32 768 kHz crystal oscillator to drive the battery backable timer e A crystal that has a frequency that is a multiple of 614 4 kHz or a multiple of 1 8432 MHz Typical val ues are 7 3728 11 0592 14 7456 22 1184 and 29 4912 MHz These crystal frequencies except 614 4 kHz and 1 8432 MHz allow generation of standard baud rates up to at least 115 200 bps The clock
55. because they may be either physical or logical Table 6 2 Origin Type Descriptions Origin Type Keyword Description flashorg Used for mapping flash non volatile bbramorg Used for mapping RAM battery backed fastramorg Used for mapping fast RAM xconorg Used for mapping xmem constants xcodorg Used for mapping xmem code xvarorg Used for mapping xmem data xmemorg Reserved for future use rconorg Used for mapping root constants rcodorg Used for mapping root code rvarorg Used for mapping root data wcodorg Used for mapping watch code resvorg Reserved origin meaning that it will not be touched by the compiler lt name gt The non terminal name though not explicitly defined in the grammar is equivalent to a C style identi fier not in the C namespace and denotes the name of the origin declared in The terminal in denotes a new concept for declaring origins the idea of a hierarchical organization or parentage Given y is a previously declared origin stating x in y denotes that x is a child of y or that y is the parent of x The name following in qualifier represents the identifier of a previously declared origin We will use the terms parent child and sibling when referring to relationships between origins The principle uses of this concept are the creation of boundary dependence and the enforcement of natural boundary constraints Much o
56. board has mir rored combined ID User blocks and the size of one image is 16 KB 0x4000 bytes then the minimum value defined for the MAX USERBLOCK SIZE macro is 32 KB 0x8000 bytes If the MAX USERBLOCK SIZE macro value is less than the actual size used for a target board s ID User blocks both Dynamic C and the RFU will fail to load to flash the part of an application that extends into the ID User blocks area This is a limitation of the pilot BIOS to allow the RFU to write a large USE 2NDFLASH CODE bin file to a two flash board the pilot BIOS does the flash writing on behalf of both Dynamic C and the RFU All of the default MAX USERBLOCK SIZE reserved space is not necessarily needed by the System ID and User blocks but reserving this much space maximizes forward binary compatibility should a product switch to any of various huge non uniform sector flash types Some of these types have sectors of 8 KB 8 KB and 16 KB at the top and the mirrored design of the User block requires that these 3 sectors be used If you do not need the User block and are not concerned with forward binary compatibility the MAX USERBLOCK SIZE macro value could be safely lowered protecting the sector containing the ID block to as little as 0x4000 16 KB but only if the System ID block is rewritten to set the User block size to zero i e no run time flash writes can occur such as to the User block or to a flash file system Reducing the MAX USERBLOCK SIZE macro
57. book rabbit com 37 6 5 1 1 Example of Origin Declarations The code from memory layout 1ib provides a practical application of origins In this section several of the origin declarations in the memory layout library are explained To simplify matters the conditional compilation macros regarding board type compile mode and separate I amp D settings in memory layout 1ib are not shown in this example A graphical representation of the regions defined by the origin declarations follows their explanation see Figure 6 2 The origin declaration syntax and semantics used in the following example are explicitly defined in Section 6 5 1 2 and Section 6 5 1 3 respectively The origin declarations shown below were taken from memory layout 1ib in Dynamic C 10 21 This library may change in future releases of Dynamic C Macros to help declare origins define ORG FLASH SIZE FLASH SIZE _ 0x1000UL define ORG RAM SIZE RAM SIZE 0x1000UL The macros _FLASH_SIZE_ and RAM SIZE are the number of 0x1000 4 KB blocks of memory avail able for Flash and RAM respectively In flash compile mode the flash is always mapped at address 0x0 define ORG FLASH START 0x0 define ORG RAM START RAM START 0x1000UL RAM START is currently defined in the main BIOS file StdBios lib orgdef flashorg flash above phy ORG FLASH START size ORG FLASH SIZE The above line defines the flash device mapping All origin definitions start with the compil
58. c C requests the CPU ID flash ID RAM size and 19200 baud rate divisor to define internally defined constants and macros Dynamic C uses the flash ID to lookup flash parameters that are sent back to the secondary loader so that it can initialize flash write erase routines At this stage the compiler can request the baud rate be increased to a higher value The secondary loader is now ready to load a BIOS and user program 11 Dynamic C now compiles the BIOS and user programs Both are compiled to a file then the file is loaded to the target using the Pilot BIOS FSM After the loading is complete Dynamic C using the Pilot BIOS FSM tells the Pilot BIOS to map flash to 0x00000 map RAM to 0x80000 and start pro gram execution at 0x0000 thereby running the compiled BIOS 12 If the Pilot BIOS detects a RAM compile or small sector flash that uses sector write mode Dynamic C uses a slightly different loading procedure The BIOS will be compiled as normal and loaded using the Pilot BIOS After the BIOS is loaded Dynamic C will tell the Pilot BIOS to start it and the rest of the program will be loaded through the compiled BIOS 13 Once the compiled BIOS starts up it runs some initialization code This includes setting up the serial port for the debug baud rate set in the Communications tab in Options Project Options setting up serial interrupts and starting the BIOS FSM Dynamic C sets a breakpoint at the beginning of main and runs the
59. ceeeeaeeatents 4 212 Memory CS ogc EE RT N NE OE NIE A 4 2 13 eel aa ER RR ER EE RE AO RR 4 Operating VOlABES EE GE EE EE E ER Se RE RE esse E a EER ES 5 ode EE EO N OE EE SENS o Through Hole re oe AE EE RE EO EE EEE 6 Moisture Sensitivity OE EA EER eee 6 Core De sig and Components RE EN EG EG N GR NG GE GN RO SEG ee N 7 LOCI A EE AA HE OE HE OE NAE T Floating IMPUS enn E E E E wei EE AARE A EEE 8 Basic RS AR AR N N EE RE ASE 9 3 3 1 Memory Access Time sis RE OR RR EE Geanveccaciees 10 3 3 2 Interfacing External I O with Rabbit 4000 DesignS esse ese see se Re GR RR ee RA Re RA ee ee ee ee 10 PC Board Layout and Memory Line Permutation iese see see ee ee ee Re ee GR Re Re Ge ee Re ee Re ee ee ee 11 PC Board Layout and Electromagnetic Interference iese esse sesse ee ee ee Re Re Re ee Re Re ee ee Re ee ee 11 3 5 1 Rabbit 4000 Low EMI Features c isccsssessscassoossssancsscssssssassstsssesssaass ses steeseasasinustzasiivvevstvosavcastaesstiy 11 How Dynamic C Cold Boots the Target SYStEM iese se se ee ee ee RA Ge Re RA ee 13 How the Cold Boot Mode Works In Detail sesse se se sk Ge GR SR GR GR Ge Ge ee ee ee Re GR ek GR GR Re ee 14 Program Loading Proc ss Overview iss tech ER EG SERE GREG ca ees needed SeSe Ge ee be 15 4 2 1 Program Loading Process Details ee ee RA RA Re Re ee Re ee Re Re Re ee ee ee ee ee Re Re Re ee 15 Rabbit Memory OroanizatiOR esse see dis ode NE AR NR in ee Se sees 17 Physical Memo Vs 2
60. ck If the data to be written is in contiguous bytes using the function writ eUserBlock is sufficient Use of writeUserBlockArray isrecommended when the data to be written is in noncontiguous bytes as may be the case for something like network configuration data See the Rabbit Micro processor Designer s Handbook for more information about the System ID and User blocks Backwards Compatibility If the System ID block on the board doesn t support the User block or no System ID block is present then the 8K bytes starting 16K bytes from the top of the primary flash are designated User block area This only works if the flash type is small sector Rabbit manufactured boards with large sector flash will have valid System ID and User blocks so is not a problem on Rabbit based boards If users create boards with large sector flash they must install System ID blocks version 3 or greater to use this function or modify this function PARAMETERS addr Address offset in the User block to write to sources Array of pointer to sources to copy data from numbytes Array of number of bytes to copy for each source The sum of the lengths in this array must not exceed 32767 bytes or an error will be returned numsources Number of data sources RETURN VALUE 0 Successful 1 Invalid address or range 2 No valid User block found block version 3 or later 3 Flash writing error LIBRARY IDBLOCK LIB 62 rabbit com The System Identificatio
61. crystal will not always give the lowest power consumption This is because when the crystal is divided internally the short chip select option can be used to reduce the chip select duty cycle of the flash memory or fast RAM greatly reducing the static current consumption associated with some memories Some applications such as a control loop may require a continuous amount of computational power Other applications such as slow data logging or a portable test instrument may spend long periods with low computational requirements interspersed with short periods of high computational load At a given operating voltage the clock speed should be reduced as much as possible to obtain the minimum power consumption that is acceptable 9 1 3 Preferred Crystal Configuration The preferred configuration for a Rabbit 4000 based system is to use an external crystal or resonator that has a frequency the maximum internal clock frequency The oscillator frequency can be doubled and or divided by 2 4 6 or 8 giving a variety of operating speeds from the same crystal frequency In addition the 32 768 kHz oscillator that drives the battery backable clock can be used as the main processor clock To save the substantial power consumed by the fast oscillator it can be turned off and the processor can run entirely off the 32 768 kHz oscillator at 32 768 kHz or at 32 768 kHz divided by 2 4 8 or 16 This mode of operation sleepy mode has a clock speed in the range o
62. d The list of supported flash memories is in Technical Note 226 Supported Flash Memories This docu ment is available online www tabbit com support techNotes_whitePapers shtml TN226 also contains information concerning the limitations of the supported flash types 10 1 Supporting Other Flash Devices Rabbit does not support flash devices other than those listed in TN226 However if you wish to use a flash memory not listed in TN226 but that still uses the same standard 8 bit JEDEC write sequences as one of the supported flash devices the existing Dynamic C flash libraries may be able to support it simply by modifying a few values Not all flash devices can be supported and the degree of support will vary depending on the flash characteristics There are two modifications to be made depending on the version of Dynamic C that you are using Step through the list below and perform each action that corresponds to your flash type 1 The flash device needs to be added to the list of known flash types This table can be found by search ing for the label FlashData in the file LIB BIOSLIB FLASHWR LIB The format is described in the file and consists of the flash ID code the sector size in bytes the total number of sectors and the flash write mode See the comments above the FlashData table in FLASHWR LIB for more information 2 The same information that was added to the FlashData table needs to be added to the FLASH INI
63. e I amp D Space Mappings in Dynamic C The next two subsections show the default MMU settings that Dynamic C uses when separate I amp D space is enabled Rabbit 4000 Designer s Handbook rabbit com 25 5 3 2 1 Compiling to RAM For RAM compiles all banks quadrants are mapped to RAM In a 20 bit physical address space i e 1 MB physical address space a 512 KB memory would be mapped with the lower 256 KB mapped to banks 0 and 2 The higher 256 KB are mapped to banks 1 and 3 In this configuration A16 is inverted to provide access to the constants and data starting at the 64K boundary The standard configuration is to set the SEGSIZE register to 0xDD so that the base segment occupies the entire 52 KB region up to the stack segment Note that this configuration causes the DATASEG register to be irrelevant The BIOS sets the MMIDR to 0x21 Bit 5 of this register enables the instruction data split and bit 0 causes the inversion of A16 Register Settings Figure 5 4 RAM Compile Memory Mapping MECR 0x0 MMIDR 0x21 SEGSIZE 0xDD DATASEG 0x0 irrelevant 0x3000 0x0000 Instruction OxCFF 0x3000 0x0000 Shared OxFFFF 0xE000 0xD000 Root Data Constants Root Code Xmem Stack Xmem Code continued xalloc Stacks N 0x1D000 Root Data 0x13000 Root Constants 0x10000 Xmem Code N OXODOOO 0x03000 Root Code 0x00000 26 rabbit com Rabbit Memory Organization 5
64. e ee ke 32 SurfacE MOUNE ese see ee ee ee Re ee Re ee Re Re ee 6 System ID block ees ee ee Re Re RA 34 51 reddine EE ee N RE E 54 EES N RE 54 WELS EE GE Ee N reer ee De ee 57 T target communications protocol sesser 16 through hole esse gs ER Se Ee veeg ese Se ees Es ES 6 UV CUS oe N Ee 15 77 troubleshooting tips iie iese see se ee ee Re 75 U USE 2NDFLASH CODE esse ese sesse se ese ee ese 36 USE TIMER PRESCALE esse ese see sesse se ese se sees 36 User Block SE MR EE 51 PEAGING AA EO EE 59 SIZES OF RR AE EN 54 ae EO o0t04 61 W Walt states sere EE EDE see ee ES Ge EG Hg 10 15 36 watch expressions ee ee ee RR RR Re Ee 36 WATCHCODESIZE ee sesse se ese see se ee ee ee ee ee Ge 36 writeenable siisii DES EE ES N Ee Ee Re Pe ge Ee 3 Write method sssri REEL ke Re ge BEE BE GRSSL GEEN Ge Gee ee 16 84 rabbit com Index
65. e of paged access is that most instructions continue to use 16 bit addressing Only when a page change is needed does a physical address transfer of control need to be made 28 rabbit com Rabbit Memory Organization As the compiler compiles code for the extended code window it checks to see if the code has passed the midpoint of the window or 0xF000 When the code passes 0xF000 the compiler generates code to slide the window down by 4 KB so that the code at FOOO x becomes resident at 0OxE000 x This automatic pag ing results in the code being divided into segments that are typically 4 KB long but which can be very short or as long as 8 KB Transfer of control within each segment can be accomplished by 16 bit address ing Between segments physical addressing 19 to 24 bit depending on configuration is required Assembly blocks are limited to 4 KB because the compiler cannot generate automatic paging code in assembly 5 5 Memory Planning Design conventions for memory configuration of a Rabbit 4000 based system specify flash and SRAM Table 5 3 Typical Interface Between the Rabbit 4000 and Memory Primary Flash SRAM Secondary Flash CSO OEO and WEO CS1 OE1 and WE1 CS2 OEO and WEO You can design a board using RAM only Details for doing so are in Section 5 6 5 5 1 Flash Code is typically stored in flash memory so the size of code must be anticipated Usually code size up to 1 MB is handled by one or
66. e region used for interrupt vectors debug kernel special variables and watch expressions This macro must only be set to 0x800 or 0x 1000 if the debug kernel is enabled and can be set to 0x400 otherwise To override the default change its value in Lib Rabbit4000 BIOSLIB StdBios c 6 4 2 Advanced Options The following macros are defined in STDBIOS c See the top of the BIOS source code and or the various configuration libraries for more options ENABLE SPREADER Default value is 1 which enables the clock spectrum spreader in normal mode to reduce EMI To override the default define ENABLE SPREADER in the project by using the Defines tab of the Project Options dialog Define the macro to 0 to disable spectrum spreading and to 2 for strong spreading NUM RAM WAITST NUM RAM2 WAITST NUM FLASH WAITST These macros are defined in boardtypes 1ib They define the number of wait states to be used for read access to RAM and flash Write access requires one more wait state than read access These macros are used to determine the relevant bit values in the memory bank control registers The only valid values for these wait state macros are 4 2 1 and 0 36 rabbit com The Rabbit BIOS MBXCR INVRT A18 MBXCR INVRT A19 These macros determine whether the MIU registers for each quadrant are set up to invert address lines A18 and A19 after the logical to physical address conversion This allows each quadrant of physical memory access up to four 25
67. ecaeseneceeeseeseenseeaeees 28 5 4 1 Placement of Code in Memory AE EE EE EE TETEE ENEE N S 28 5 4 2 Paged Access in Extended Memory c cccccesessseeseescceseseceseeseceseeeeeaeceeeeseseeesaeeneesaeeeaeeaeeeaeearenss 28 3 9 Memory Planning ssegar EA EE OE a e AER S E ANEAN 29 e A E AE LAER NE OE OE E E EA E E OE E 29 RS DES corsaris in nE EE E E R 29 5 6 Making a RAM Only Board sesse sense RR NE see GER Eg Ge RSA SEKER Sek Re NR Ge RGN eg GERS NEGE DERE SR Ge N Deed SR gee RR ee 30 5 6 1 Hardware Chan 2 RA RE N N OE RA EEEE aA 30 5 6 2 Software Changes sccsscssscsscssssssesssscsssnsssessescesseesssessesssesseeesssessnssuesusscesseeseasseseesensesesensenseess 30 CnapterG The Rabbit BIOS SENSE ee eN ke ed EA EG Ge eN NE GN Gee ee NG RE 31 6 1 Startup Conditions Set by the BIOS ee ee ee RR Re RA Re RR ee Re Re Gee RA GR Re Re Re ee ee ee 32 6 1 1 Registers Initialized in the BIOS ee ee ee AA RA GR Re Re AA ee Re Re Re Re ee Re ee ee 32 6 V2 8ste AE EE N EO 32 6 2 BIOS Flo wel RD RE EE RO EE EE EN 33 6 3 Internally Defimed Macross sisie ke se ER de ER Ee Nes ERGE ERENS NEG REG EG GEN be ASe es N Gog bee VER Seg REEN ed P PESIS SAP ek ee 34 64 Modifying the BIOS sis see cs cccnpecvupscedncspesccuuqsiyce dauegvacinvacehesicesgeadesblay Seks ee oe ge ae vag de ene RD Es ED ER EK 34 6 4 1 Macros that Affect the BIOS ee ee ee Re RA RA RA GR Re Re ee Re ee Re Re Re Re ee Re ee ee 35 64 2 GEE 9 GEE OE EE N
68. ee Technical Note 218 Implementing a Serial Download Manager for a 256K Byte Flash for more information on the later This document is available at rabbit com docs app tech notes shtml 6 5 1 Origins Starting with Dynamic C 10 21 The origin directives are all collected in a single library memory layout lib which is use d in the BIOS The origins are arranged as a hierarchy of child and parent origins memory regions with a common parent called the root origin which is essentially an abstract representation of all memory The root origin is never explicitly defined but any origin declaration not having a named parent origin is a child of the root origin The hierarchical arrangement provides a mechanism by which child origins recursively inherit the properties of their parent origins This allows for better error checking of the memory mapping itself since the compiler can check that a data origin is not defined in a region mapped as flash memory for example The example in Section 6 5 1 1 illustrates this functionality In addition to the inheritable properties the origin directives use relative memory mapping Relative memory mapping allows for more flexible descriptions of memory configurations since the syntax allows rules to be enforced on the placement of particular regions of memory with respect to one another without having to account for the actual boundaries of those regions Rabbit 4000 Designer s Hand
69. er directive orgdef Note that the origin type is flashorg and the origin has the user defined name flash The flashorg origin type has the property of being non volatile The syntax above phy ORG FLASH START indicates that the origin is a child of the root origin starting at the physical address defined by the macro ORG FLASH START The final piece size FLASH SIZE defines the size of the flash region this is often the size of the device for flashorg and ramorg origin types orgdef resvorg user block in flash below end size MAX USERBLOCK SIZE The above line defines the user block space as an origin called user block The type resvorg indi cates that the region is a reserved origin that should not be touched by the compiler The syntax in flash makes the origin a child of the origin named flash defined previously Following the inheritance below end indicates that the origin should be at the end of its parent in this case the origin called flash The region has size MAX_USERBLOCK_SIZE orgdef bbramorg ram above phy ORG RAM START size ORG RAM SIZE Traditional Rabbit memory configurations have a primary SRAM device that is also battery backed This line defines the primary RAM device as a battery backed RAM origin bbramorg origin type with the name ram The origin is a child of the root origin starts at the physical address ORG_RAM_START and has size ORG_RAM
70. erdown functions the Realtek chip can be placed in and awakened from its own power down mode Note that no TCP IP or Ethernet functions should be called while the Realtek is powered down 9 2 6 Baud Rates in Sleepy Mode The available baud rates in sleepy mode are 1024 1024 2 1024 3 1024 4 etc Baud rate mismatches of up to 5 may be tolerated The baud rate 113 77 is available as 1024 9 and may be useful for communicat ing with other systems operating at 110 bps a 3 4 mismatch In addition the standard PC compatible UART 16450 with a baud rate divider of 113 generates a baud rate of 1019 bps a 0 5 mismatch with 1024 bps If there is a large baud rate mismatch the serial port can usually detect that a character has been sent to it but can not read the exact character 9 2 7 Debugging in Sleepy Mode Debugging is not supported in sleepy modes However running with no polling Alt F9 will avoid the loss of target communications when execution enters sections of code using sleepy mode and debug com munications will resume when the normal operation mode is reenabled 72 rabbit com Low Power Design and Support Semiconductor 10 Supported Flash Memories There are many flash memories that have been qualified for use with the Rabbit 4000 microprocessor Both small and large sector flash devices are supported To incorporate a large sectored flash into an end product the best strategy is have a small sectored development boar
71. erface it is easy to design hardware in a Rabbit 4000 based system More details on hardware design are given in the Rabbit 4000 Microprocessor User Manual 2 1 Design Conventions e Include a standard Rabbit programming cable The standard 10 pin programming connector provides a connection to serial port A and allows the PC to reset and cold boot the target system e Connect a static RAM having at least 128 KB to the processor using CS1 OE1 and WE1 It is useful if the PC board footprint can also accommodate a RAM large enough to hold all the code anticipated Although code residing in some flash memory can be debugged debugging and program download is faster to RAM e Connect a flash memory that is on the approved list and has at least 128 KB of storage to the processor using CS0 OE0 and WEO Non approved memories can be used but it may be necessary to modify several files Some systems designed to have their program reloaded by an external agent on each pow erup may not need any flash memory e Install a crystal oscillator with a frequency of 32 768 kHz to drive the battery backable real time clock RTC the watchdog timer WDT and the Periodic Interrupt e Install a crystal or oscillator for the main processor clock that is a multiple of 614 4 kHz or better a multiple of 1 8432 MHz These preferred clock frequencies make possible the generation of standard serial baud rates Common crystal frequencies to use are 7 3728 MHz
72. es checks a few error conditions and then before starting compilation of the application selects which BIOS file to activate The default BIOS is Lib Rabbit4000 BIOSLIB StdBios c 34 rabbit com The Rabbit BIOS 6 4 1 Macros that Affect the BIOS There are several macros that may be modified for custom designed boards or for special situations involving off the shelf Rabbit 4000 based boards The following list is not exhaustive CLOCK DOUBLED Default value of 1 causes the clock speed to be doubled Setting this to zero means the clock speed will not be doubled To override the default define CLOCK DOUBLED to zero in the project by using the Defines tab of the Project Options dialog CS1 ALWAYS ON Default value of 0 disables the feature of keeping CS1 always active To override the default define CS1 ALWAYS ON to 1 in the project by using the Defines tab of the Project Options dialog Keeping CS1 always active is useful if your system is pushing the limits of RAM access time It will increase power consumption a little DATAORG This macro is deprecated Use ROOT SIZE 4K instead ROOT SIZE 4K This macro defines the number of 4 kilobyte pages used for the base segment The default is 3 when sepa rate I amp D space is enabled and 6 otherwise To override the default define ROOT SIZE 4K in the project by using the Defines tab of the Project Options dialog Increasing this value increases the size of root constants when se
73. es you will be able to write diagnostic programs suited for your unique board design 76 rabbit com Troubleshooting Tips for New Rabbit Based Systems 11 2 2 Diagnostic Test 1 Toggle the Status Pin This test toggles the status pin 1 Apply the reset for at least 1 4 second and then release the reset This enables the cold boot mode for asynchronous serial port A if the programming cable is connected to the target s programming connec tor 2 Send the following sequence of triplets 80 OE 20 sets status pin low 80 OE 30 sets status pin high 80 OE 20 sets status pin low again 3 Wait for approximately 1 4 second and then repeat starting at step 1 While the test is running an oscilloscope can be used to observe the results The scope can be triggered by the reset line going high It should be possible to observe the data characters being transmitted on the RXA pin of the processor or the programming connector The status pin can also be observed at the processor or programming connector Each byte transmitted has 8 data bits preceded by a start bit which is low and fol lowed by a stop bit which is high viewed at the processor or programming connector The data bits are high for 1 and low for 0 The cold boot mode and the triplets sent are described in Section 4 1 on page 14 Each triplet consists of a 2 byte address and a 1 byte data value The data value is stored in the address specified The uppermost bit of the 16
74. et enabled boards do not have the EEPROM with the MAC address These boards can still be used as a clone because the MAC address is in the system ID block and this structure is shipped on the board and is not overwritten by cloning unless CL INCLUDE ID BLOCKS is set to one If you have a custom designed board that does not have the EEPROM or the system ID block you may download a program at http www rabbit com support feature downloads html to write the system ID block which contains the MAC address to your board To purchase a MAC address go to http standards ieee org regauth oui index shtml 8 3 2 Different Flash Types Since the BIOS supports a variety of flash types the flash EPROM on the two controllers do not have to be identical Cloning works between master and clone controllers that have different type flash chips because the master copies its own universal flash driver to the clone The flash driver determines the particulars of the flash chip that it is driving 8 3 3 Different Memory Sizes It is recommended that the cloning master and slave both have the same RAM and flash sizes 8 3 4 Design Restrictions Digital I O line PB1 should not be used in the design if cloning is to be used Rabbit 4000 Designer s Handbook rabbit com 65 66 rabbit com BIOS Support for Program Cloning Semiconductor 9 Low Power Design and Support With the Rabbit 4000 microprocessor it is possible to design systems that
75. f 2 kHz to 32 kHz and a VDD_ core current consumption in the range of 14 to 22 uA depending on frequency and voltage Figure 9 1 Rabbit 4000 Clock Distribution External 32 kHz 16 8 4 2 1 SE Crystal Oscillator evices NOTE Peripherals can not be clocked slower than the CPU To watchdog timer and time date clock Rabbit 4000 Designer s Handbook rabbit com 69 9 2 To Further Decrease Power Consumption In addition to the low power features of the Rabbit 4000 microprocessor other considerations can reduce power consumption by the system 9 2 1 What To Do When There is Nothing To Do For the very lowest power consumption the processor can execute a long string of mu1 instructions with the DE and BC registers set to zero Few if any internal registers change during the execution of a string of mul zero by zero and a memory cycle takes place only once in every 12 clocks 9 2 2 Sleepy Mode Power consumption is dramatically decreased in sleepy mode The VDD_ core current consumption is often reduced to the region of 22 uA 3 3 V and 32 768 kHz The Rabbit 4000 executes about 6 instructions per millisecond at this low clock speed Generally when the speed is reduced to this extent the Rabbit will be in a tight polling loop looking for an event that will wake it up The clock speed is increased to wake up the Rabbit In sleepy mode most of the power is consumed by memory e the p
76. f the remaining syntax becomes very natural when following the implica tions of this concept Another key concept in the child parent model of origin declarations is the notion that child origins remove space from their parents The reason for this is that we are still modeling a linear memory space The hierarchy is simply a way to organize the information in a dependent manner which obviates the macro verbosity that was previously required by origin declarations As shown in the examples above each origin represents an entire space of a particular origin type Child origins transfer space from their parents to themselves The remaining space in the parent origin is fragmented automatically by the com 42 rabbit com The Rabbit BIOS piler At the end of the origin declaration section all that remains is a flattened map that represents the true layout of memory in the physical space lt placement gt The non terminal placement denotes the placement of an origin within a larger parent space relative to the beginning of that parent in the absence of the in qualifier the parent can be considered to be all of the physical memory or root The placement non terminal is either the fill terminal or the non ter minal lt vector gt followed by the non terminal size The vector non terminal is not a vector in the math ematical sense but rather denotes a position and an orientation An origin may be declared
77. frequency can be doubled by an on chip clock doubler but the doubler should not be used to achieve frequencies higher than about 60 MHz on a 3 3 V system A quartz crystal should be used for the 32 768 kHz oscillator For the main oscillator a ceramic resonator that is accurate to 0 5 will usually be adequate and less expensive than a quartz crystal for lower frequencies 4 rabbit com Rabbit Hardware Design Overview 2 2 Operating Voltages The operating voltage in Rabbit 4000 based systems will usually be 1 8 V 10 for the processor core and 3 3 V 10 for the I O The VO ring can also be run at 1 8 V 10 The maximum computation per watt is obtained in the range of 3 0 V to 3 6 V The highest clock speed requires 3 3 V The maximum clock speed with a 3 3 V supply is 54 MHz 26 7264 x 2 but it will usually be convenient to use a 14 7456 MHz crystal doubling the frequency to 29 4912 MHz Good computa tional performance but not the absolute maximum can be implemented for a 3 3 V system by using an 11 0592 crystal and doubling the frequency to 22 1184 MHz Such a system will operate with 70 ns memo ries A 29 4912 MHz system will require memories with 55 ns access time A table of timing specification is in the Rabbit 4000 Microprocessor User Manual 2 3 Power Consumption Various mechanisms contribute to the current consumption of the Rabbit 4000 processor while it is operat ing including current that is proportional to the
78. gs e The I O bus can be separate from the memory bus e The external processor bus cycles are not all the same length e The external processor bus does not require running the clock around the PCB e The clock spectrum spreader option modulates the clock frequency e Some gated internal clocks are enabled only when needed e An internal clock doubler allows the external crystal oscillator to operate at 1 2 frequency Rabbit 4000 Designer s Handbook rabbit com 11 12 rabbit com Core Design and Components Semiconductor 4 How Dynamic C Cold Boots the Target System Dynamic C assumes that target controller boards using the Rabbit 4000 CPU have no pre installed firm ware It takes advantage of the Rabbit 4000 s bootstrap cold boot mode which allows memory and I O writes to take place over the programming port Figure 4 1 Rabbit Programming Port Circuit Board with Rabbit 4000 Processor Programming RABBIT 4000 Header Programming Header Pinout The Rabbit programming cable is a smart cable with an active circuit board in its middle The circuit board converts RS 232 voltage levels used by the PC serial port to CMOS voltage levels used by the Rabbit 4000 The level converter is powered from the power supply voltage present on the Rabbit 4000 program ming connector Plugging the programming cable into the Rabbit programming connector results in pull ing the Rabbit 4000 SMODEO and SMODE 1 startup mode lines
79. h will have valid System ID and User blocks so this should not be a problem on Rabbit based boards 7 2 1 Boot Block Issues The System ID and User block implementations have been designed to accommodate huge non uniform sector flash types but it is necessary to use T type parts with such flash types so that the smaller boot block sectors at the top can be used for the blocks B parts have smaller boot block sectors at the bottom No code is included with Dynamic C to lock boot blocks and users should not lock boot blocks unless they are sure they will never write to the blocks after the System ID block is written If a boot block lock is irreversible we strongly recommend never locking it Rabbit 4000 Designer s Handbook rabbit com 57 7 2 2 Reserved Flash Space The macro MAX USERBLOCK SIZE default 0x8000 in the BIOS tells the Dynamic C compiler how much flash at the top of the primary flash is excluded from use by the compiler for xmem functions For any application whether compiled to a single target board or for multiple target boards the MAX USERBLOCK SIZE macro value defined in RabbitBios c must not be lower than the amount of flash required for the System ID User blocks on the target board with the largest requirement Note that in the case of mirrored combined ID User blocks version 3 and up the amount of flash that must be reserved is double the size of one combined ID User block image For example if a target
80. hat this SRAM consumes about 14 mA At the same frequency with the short chip select enabled the SRAM consumes about 23 1 A a substantial reduction in power consumption As shown both special chip select modes i e short chip select and self timed chip select reduce memory current consumption since the processor spends most of its time performing reads i e instruction fetches The self timed chip select feature is available in sleepy and ultra sleepy mode i e when the processor is running off the 32 kHz oscillator or when the oscillator is divided by 2 4 8 or 16 The short chip select feature may be used when the main oscillator is divided by 4 6 or 8 This division can be done regardless of whether the clock doubler is on or off Currently interrupts must be disabled when both the short chip select feature is enabled and an I O instruction is used Interrupts can be disabled for a single I O instruction by using code such as push ip save interrupt state ipset 3 interrupts off ioe ld a hl typical I O instruction pop ip reenable interrupts NOTE Short chip selects and self timed chip selects only take place during memory reads During writes the chip selects behave normally For a detailed description of the chip select features please see the Rabbit 4000 Microprocessor User s Manual 68 rabbit com Low Power Design and Support 9 1 2 Reducing Clock Speed It is important to know that the lowest speed
81. he 32 768 kHz clock is used for the battery backable clock also known as the real time clock the watchdog timer the periodic interrupt timer and the asyn chronous cold boot function Rabbit 4000 Designer s Handbook rabbit com 7 Figure 3 1 Main Oscillator Circuit NC7SZU04 gt O CLKIEN The 32 768 kHz oscillator is slow to start oscillating after power on For this reason a wait loop in the BIOS waits until this oscillator is oscillating regularly before continuing the startup procedure The startup delay may be as much as 5 seconds but will usually be about 200 ms Crystals with low series resistance R lt 35 kQ will start faster For more information on the 32 768 kHz oscillator please see Technical Note 235 External 32 768 kHz Oscillator Circuits This document is available on our website www rabbit com 3 2 Floating Inputs Floating inputs or inputs that are not solidly either high or low can draw current because both N and P FETs can turn on at the same time To avoid excessive power consumption floating inputs should not be included in a design except that some inputs may float briefly during power on sequencing Most unused inputs on the Rabbit 4000 can be made into outputs by proper software initialization to remove the floating property Pull up resistors will be needed on a few inputs that cannot be programmed as outputs An alter native to a pull up resistor is to tie an
82. igin declaration start and end syntax lt Start gt orgstart lt end gt orgend Origin application syntax lt orguse gt orgact lt name gt lt action gt lt action gt apply resume Origin macro declaration syntax lt macdef gt orgmac lt define gt lt define gt lt name gt lt orgval gt lt orgval gt lt name gt lt int gt lt boundary gt lt aspect gt lt aspect gt lt quality gt lt position gt size fragments lt quality gt physical logical segment lt position gt start end 6 5 1 3 Origin Declaration Semantics The formal semantics of the origin declaration syntax are explained in this section lt decl gt The non terminal decl represents an origin declaration All origin declarations begin with orgdef lt type gt The non terminal type represents two subcategories of origins physical origins and logical origins Physical origins do not require a logical beginning and ending address because they are not accessed through logical addresses or if they are then through the xmem window which is fixed This distinction has no obvious effect on the grammar as it is written but influences a semantic restriction discussed later Rabbit 4000 Designer s Handbook rabbit com 41 Physical origins are represented by the phy_org non terminal and logical origins by log_org The origin types wcodorg and resvorg are exceptional
83. ing 16 KB from the top of the primary flash are designated the User block area However to prevent errors arising from incompatible large sector configurations this will only work if the flash type is small sector Rabbit manufactured boards with large sector flash will have valid System and User ID blocks so this should not be problem on Rabbit based boards If users create boards with large sector flash they must install System ID block version 3 or great er to use this function or modify this function PARAMETERS addr Address offset in User block to write to source Pointer to destination to copy data from numbytes Number of bytes to copy RETURN VALUE 0 Successful 1 Invalid address or range 2 No valid User block found block version 3 or later 3 Flash writing error LIBRARY IDBLOCK LIB Rabbit 4000 Designer s Handbook rabbit com 61 writeUserBlockArray int writeUserBlockArray unsigned addr void sources unsigned numbytes int numsources DESCRIPTION Rabbit based boards are released with System ID blocks located on the primary flash Version 2 and later of this ID block has a pointer to a User block that can be used for storing calibration con stants passwords and other non volatile data The User block is protected from normal write to the flash device and can only be accessed through this function or writeUserBlock This function writes a set of scattered data from root memory to the User blo
84. it are discussed in Technical Note 235 available on our website www rabbit com 9 2 4 Conformal Coating of 32 768 kHz Oscillator Circuit The 32 768 kHz oscillator circuit consumes microampere level currents The circuit also has very high input impedance thus making it susceptible to noise moisture and environmental contaminants To avoid leakage due to moisture and ionic contamination it is recommended that the oscillator circuit be conformal coated This is simplified if all components are kept on the same side of the board as the processor Feedthroughs that pass through the board and are connected to the oscillator circuit should be covered with solder mask that will serve as a conformal coating for the back side of the board from the processor Please see Technical Note 303 Conformal Coating and Technical Note 235 External 32 768 kHz Oscillator Circuits on the Rabbit website for more information www rabbit com support techNotes whitePapers shtml 9 2 5 Software Support for Sleepy Mode In sleepy mode the microprocessor executes instructions too slowly to support most interrupts Data will probably be lost if interrupt driven communication is attempted The serial ports can function but cannot generate standard baud rates when the system clock is running at 32 768 kHz or below The 48 bit battery backable clock continues to operate without interruption Usually the programmer will want to reduce power consumption to a minimu
85. k 2 then scale down timer A to make the serial port divi sor fall below 256 Timer A can be clocked by the peripheral clock PCLK in addition to the default which is the peripheral clock 2 PCLK 2 Furthermore the asynchronous serial port data rate can be 8x the clock in addition to the default of 16x the clock Therefore in addition to the equation above the following equations may be used to find the asynchronous divisor for a given clock frequency Timer A clocked by PCLK 2 serial data rate 16 x clock CPU frequency in Hz oo 16 x 2 x baud rate Timer A clocked by PCLK serial data rate 16 x clock CPU frequency in Hz 1 eee 16 x baud rate Timer A clocked by PCLK 2 serial data rate 8 x clock CPU frequency in Hz ar 8 x 2 x baud rate Timer A clocked by PCLK serial data rate 8 x clock CPU frequency in Hz 1 divisor 8 x baud rate 82 rabbit com Supported Rabbit 4000 Baud Rates Semiconductor Index A D A18 and A19 inversion iese see ee ee RA 37 DATAORG i s EE EE EG Re EE ek Ee ee EER Ee 35 ACCESS TIMES ee 5 9 10 32 35 55 56 DATASEG register see sees see ee ee Re 16 32 debug mode EE MA OE EET 16 70 B design CONVENTIONS ees see ee ee AR Re Re ee Re 3 bank Size ees ee ee ee ee Re Re ee I EEEa 32 memory CHIPS RR RR RRRRRRRRRRRR RR RR BRek 4 base segment iss EER ss eek lates ERNA SE GE Rek Ee es 32 oscillator crystals ER OE 4 baud rates eieiei aaraa 1
86. lined on the label only apply to components that will be exposed to SMT processing This means that completed board level products that will not be subjected to the solder reflow processing do not have to be baked or sealed in special moisture barrier bags 6 rabbit com Rabbit Hardware Design Overview Semiconductor 3 Core Design and Components Core designs can be developed around the Rabbit 4000 microprocessor A core design includes memory the microprocessor oscillator crystals the Rabbit 4000 standard programming port and in some cases a power controller and power supply Although modern designs usually use at least four layer printed circuit boards two sided boards are a viable option with the Rabbit 4000 especially if the clock speed is not high and the I O is intended to operate at 3 3 V factors that reduce edge speed and electromagnetic radiation Schematics illustrating the use of the Rabbit 4000 microprocessor are available online via links in the man uals for the products that are using the Rabbit 4000 Each board level or core module product has a user manual with an appendix labeled Schematics Go to www rabbit com and select Product Documenta tion from the Support tab this will take you to a list of links for available user manuals 3 1 Clocks The Rabbit 4000 has input pins for both the fast clock and the 32 768 kHz clock The fast clock drives the Rabbit 4000 CPU and peripheral clocks whereas t
87. ly it may be the non terminal quality followed by position as explained below lt quality gt This non terminal specifies a quality of a particular boundary and may be any of the terminal symbols physical logical or segment Each correspond to the physical address logical address and segment value respectively of the origin boundary in context If the origin is not a logical origin then the segment and logical terminals will represent the physical boundary converted to an xxx Exxx address type lt position gt The position non terminal is either start or end and represents the beginning or end respectively of the origin in context 6 5 2 Origins Prior to Dynamic C 10 21 The following grammar in BNF describes the syntax used for the declaration of origin statements prior to Dynamic C version 10 21 origin directive origin type identifier origin designator origin designator action expression origin declaration origin declaration physical address size follow qualifier I amp D qualifier action qualifier debug qualifier origin type rcodorg xcodorg wcodorg wvarorg rvarorg rconorg follow qualifier 01 lows identifier splitbin I amp D qualifier ispace dspace action qualifier resume apply size constant expression physical address constant expression constant expression The non terminals identifier and constant expression are defined in the ANSI C specification Basically a
88. m for a fixed time period or until some external event takes place On entering sleepy mode by calling use32kHzOsc the peri odic interrupt is completely disabled the system clock is switched to 32 768 kHz and the main oscillator is powered down The device may be run even slower by dividing the 32kHz oscillator by 2 4 8 or 16 with the set 32kHzDivider call When the 32kHz oscillator is divided these slower modes are called ultra sleepy modes On exiting sleepy mode by calling useMainOsc the main oscillator is powered up a time delay is inserted to be sure that it has resumed regular oscillation and then the system clock is switched back to the main oscillator At this point the periodic interrupt is reenabled While in sleepy mode the user may call updateTimers periodically to keep Dynamic C time vari ables updated These time variables keep track of seconds and milliseconds and are normally used by Dynamic C routines to measure time intervals or to wait for a certain time or date updateTimers reads the real time clock and then computes new values for the Dynamic C time variables The normal method of updating these variables is the periodic interrupt that takes place 2048 times per second NOTE In ultra sleepy modes calling updateTimers is not recommended Rabbit 4000 Designer s Handbook rabbit com 71 Functions are provided to power down the Realtek Ethernet chip as well By calling the pd_powerup and pd_pow
89. may be desirable e Extended Memory a k a xmem can be used for code and data such as communications applica tions or data logging applications The amount needed depends on the application Rabbit 4000 Designer s Handbook rabbit com 29 5 6 Making a RAM Only Board Some Rabbit 4000 customers are designing boards that have a single RAM chip and no flash memory Although this is not recommended it may be safe as long as the board has a continuous power supply and is set up to be field programmable via the Rabbit 4000 bootstrap mode For example a Rabbit 4000 based board in a noncritical system such as a lawn sprinkler system may be monitored from a remote location via the Internet or Ethernet where the remote monitor has the ability to reload the application program to the board One way to achieve field programmability is with the RabbitLink Network Gateway There are certain hardware and software changes that are required to make this work 5 6 1 Hardware Changes Ordinarily CS0 OEO and WEO of the Rabbit 4000 processor are connected to a Flash chip and CS1 OE1 and WE1 are connected to RAM However if only RAM is to be used CS0 OEO and WEO must be connected to the RAM This is because on power up or reset the Rabbit 4000 will begin fetching instructions from whatever is hooked to CS0 OEO and WEO 5 6 2 Software Changes To program a RAM only board from Dynamic C or the Rabbit Field Utility RFU several changes
90. n and User Blocks Semiconductor 8 BIOS Support for Program Cloning The BIOS supports copying designated portions of flash memory from one controller the master to another the clone The Rabbit Cloning Board connects to the programming port of the master and to the programming port of the clone This simple circuit can easily be incorporated into test fixtures for fast pro duction Figure 8 1 Cloning Board RXA GND lt CLKA _ Connect Connect to Master s to Clone s Programming Port Programming Port 8 1 Overview of Cloning If the cloning board is connected to the master the signal CLKA is held low This is detected in the BIOS after the reset ends invoking the cloning support of the BIOS If cloning has been enabled in the master s BIOS it will cold boot the target system by resetting it and downloading a primary boot program The master then sends the entire user program along with other user selected portions of flash memory to the clone where the boot program receives it and stores it in RAM then copies it to flash Optionally the cloned program can begin running on the slave For more details on cloning see Technical Note 207 Rabbit Cloning Board available at rabbit com Rabbit 4000 Designer s Handbook rabbit com 63 8 2 Creating a Clone Before cloning can occur the master controller must be readied Once this is done any number of clones may be created from the same master
91. n identifier is a sequence of letters and digits that must start with a letter The underscore character is considered a letter The definition of constant expression is more involved as it winds up the restricted subset of operators that are allowed in the evaluation of the expression but the result is a constant For a comphrensive definition of the non terminals identifier and constant expression please refer to Appendix A in The C Programming Language by Kernighan and Ritchie 6 5 2 1 Origin Directive Semantics An origin directive associates a code pointer and a memory region with a particular type of code The type of code is specified by origin type Rabbit 4000 Designer s Handbook rabbit com 45 Table 6 3 Origin Types Recognized by the Compiler Origin Type Keyword root code rcodorg xmem code xcodorg watch code wcodorg watch code wvarorg root data rvarorg root constants rconorg All code sections rcodorg xcodorg code and wcodorg grow up All non constant data sections rvarorg grow down Root constants are generated to the rcodorg region when separate I amp D space is disabled When separate I amp D space is enabled root constants are generated to the rconorg region xdata and xstring are generated to the current xcodorg region All origin directives must have a unique ANSI C identifier The scope of this identifier is only with other origin directives or declarations 6 5 2 2 Defi
92. ning a Memory Region Each memory region is defined by calculating a physical address from an 8 bit base address first constant expression of physical address and a 16 bit logical address second constant expression of physical address The size of the memory region is determined by 20 bit size Overflow of these three values is trun cated 6 5 2 3 Action Qualifiers The keywords apply and resume are action qualifiers They tell the compiler to generate code or data in the memory region specified by identifier An apply action resets the code or data pointer for the spec ified region to the starting physical address of the region and makes the region active A resume action does not reset the code or data pointer but does make the memory region active A region remains active i e the compiler will continue to generate code or data to it until another region of the same origin type is activated with an apply or resume action or until the memory region is full 6 5 2 4 I amp D Qualifiers The ispace and dspace qualifiers suppress compiler warnings regarding collisions between the two logical regions and the physical memory space When an ispace or dspace qualifier is used in an ori gin directive that directive is no longer collision checked against origin directives in the other space For example a rcodorg directive with the ispace qualifier is not checked against any origin directives with a dspace qualifier 46 rabbit com The Ra
93. nly contain a serial boot flash and SRAM On these boards the program is copied into the SRAM at boot time from the serial flash The program is then executed from static RAM Trying to use a single parallel flash memory chip to store both a program and live data that must be fre quently changed can create software latency problems When data are written to a small sector flash mem ory the memory is inoperative during the 5 to 20 ms that it takes to write a sector If the same memory is used to hold data and the program then the execution of code must cease during this write time The 5 20 ms is timed out by a small routine executing from root RAM while system interrupts are disabled effec tively freezing the system for 5 20 ms The 5 20 ms lockup period can adversely affect real time opera tion 18 rabbit com Rabbit Memory Organization 5 2 Memory Segments From the point of view of a Dynamic C programmer there are a number of different uses of memory Each memory use occupies a different segment in the logical 16 bit address space The four segments are shown in Figure 5 1 Figure 5 1 Memory Map of 16 bit Logical Address Space MMU Register Value Ox3FEFFFF MECR 0x40 Xmem Segment 7 Stack Seek Segment Data Segment or Base Segment 0x0000 Logical Address Space Physical Address Space OxFFFF Quadrant 3 Ox2FFFFF 0xE000 oa aa Ox1FFFFF Quadrant 1_ o oFFFFF 0x060000 Root Code Quadran
94. ocessors up to 1 MB of code can be efficiently executed by moving the mapping of the 8 KB window using special instructions that are designed for this purpose long call LCALL long jump LJP and long return LRET Dynamic C currently supports up to 1MB of code using these instructions The Rabbit 4000 processor allows up to 16 MB of code using new extended ver sions of these instructions long long call LLCALL long long jump LLJP and long long return LLRET The xmem segment is a window into the physical address space Using the appropriate segment register XPC or LXPC any logical address in the range 0xE000 to OxFFFF can be mapped to any address in the physical address space Consider the following examples Table 5 2 Mapping Xmem Addresses Segment Register Logical Address Mapping Equation Physical Address XPC OXFE OxE74F OxFE000 OxE74F Ox10C74F 0x10C74F LXPC OXOFE OxE74F OxOFE000 OxE74F 0x10C74F 0x10C74F XPC OxF2 0xE000 OxF2000 0xE000 0x100000 0x100000 LXPC OxFFO OxFFFF OxFF0000 OXFFFF OxFFFFFF 0xFFFFFF WARNING The XPC is used for addressing up to 1 MB and the LXPC is used for addressing up to 16 MB Mixing the use of the XPC and LXPC is dangerous Please see Technical Note 202 Rabbit Memory Management in a Nutshell for more details on how memory mapping works on the Rabbit 2000 and Rabbit 3000 This document is available at rabbit com 22 rabbit
95. of reserving a block of memory so that xalloc does not use it has also changed To reserve a block of memory in DC 9 30 and later the resvorg should be used All other origins e g rcodorg rvarorg etc are also tracked by the compiler and those blocks are entered into the origin table generated by the compiler so they are not used by xalloc The resvorg is used as follows resvorg lt NAME gt segment offset size reserve For example the following code would reserve the entire flash memory in flash compile mode resvorg flashmem 0x0 0x0 0x80000 reserve The reserve keyword must be added to the end to reserve the entire block of memory Some applications may require that fixed regions of RAM be reserved for their own use For example you may want to reserve the upper half of a512K RAM in Flash compile mode To reserve this you need to add the following line of code to LIB BIOSLIB STDBIOS C just below the resvorg removeflash 0x0 0x0 0x80000 reserve ifdef RESERVE UPPER RAM resvorg reserveupperram 0xC0 0x0 RESERVE UPPER RAM batterybacked reserve endif This tells the compiler to reserve RESERVE UPPER RAM bytes from physical address 0xC0000 by add ing it to the origin table This removes this memory block from the available xalloc memory In the Defines tab of the Options Project Options dialog enter the amount of memory you want to reserve For example RESERVE UPPER RAM 0x40000 would reserve physical memory f
96. om The System Identification and User Blocks Note that it is especially difficult to effectively reduce the MAX USERBLOCK SIZE macro value below 0x4000 16 KB for the BL20xx or BL21xx board families which have their combined ID User blocks size hard coded in the FLASHWR LIB and IDBLOCK LIB libraries because their stored calibration con stants are in a nonstandard place For this reason Rabbit strongly recommends not attempting to make System ID User block changes on these board families 7 2 3 Reading the User Block readUserBlock int readUserBlock void dest unsigned addr unsigned numbytes DESCRIPTION Reads a number of bytes from the User block on the primary flash to a buffer in root memory NOTE portions of the User block may be used by the BIOS for your board to store values such as calibration constants See the manual for your particular board for more information before overwriting any part of the User block PARAMETERS dest Pointer to destination to copy data to addr Address offset in User block to read from numbytes Number of bytes to copy RETURN VALUE 0 Successful 1 Invalid address or range 2 No valid System ID block found LIBRARY IDBLOCK LIB Rabbit 4000 Designer s Handbook rabbit com 59 readUserBlockArray int readUserBlockArray void dests unsigned numbytes int numdests unsigned addr DESCRIPTION Reads a number of bytes from the User block on the primary flash to a set of b
97. ors Circuits that continuously draw power a Ordinary CMOS logic uses power when it is switching from one state to another The power drawn while switching is used to charge capacitance or is used when both N and P field effect transmitters FETs are simultaneously on for a brief period during a transition Rabbit 4000 Designer s Handbook rabbit com 67 9 1 Details of the Rabbit 4000 Low Power Features This section goes into more detail about the Rabbit 4000 low power features 9 1 1 Special Chip Select Features Unlike competitive processors the Rabbit 4000 has two special chip select features designed to minimize power consumption by external memories This is significant because if not handled well external memo ries can easily become the dominant power consumers at low clock frequencies Primarily because most memory chips draw substantial current at zero frequency When the chip select and output enable are held enabled and all other signals are held at fixed levels In situations where the microprocessor is operating at slow frequencies such as 2 048 kHz the memory cycle is about 488 us and the memory chip spends most of its time with the chip enable and the output enable on The current draw during a long read cycle is not specified in most data sheets The Hynix HY62KF08401C SRAM according to the data sheet typically draws SmA MHZ when it is operating When performing reads at 2 048 kHz we ve found t
98. parate I amp D space is enabled and root code when it is disabled The sum of available root and data is constant such that increasing one decreases the other This macro can be changed to as high as 11 and as low as 1 when sepa rate I amp D space is enabled or as low as 3 when separate I amp D space is disabled ENABLE CLONING Default value of 0 disables cloning To override the default define ENABLE CLONING to 1 in the project by using the Defines tab of the Project Options dialog This slightly increases the code size of the BIOS If cloning is used PB1 should be pulled up with 50K or so pull up resistor On some Rabbit core modules such as the RCM4200 the PB1 CLKA signal is either not available or not pulled up on the programming port The master can be forced to invoke cloning support by setting CL FORCE MASTER MODE tol This will cause the BIOS to assume a cloning cable is attached on every startup assuring that only the cloning code will run Note that defining CL FORCE MASTER MODE to 1 will not allow the program on the board to run that is the board will act only as a clone master While compiling to the target with CL FORCE MASTER MODE set to 1 the loss of target communica tion is expected and unavoidable After the program has loaded and target communication is lost the clone master will still correctly perform its cloning function after a cloning cable is attached Various cloning options are available when ENABLE CLONING is
99. perform their tasks with very low power consumption The Rabbit has several features that contribute to low power consumption They are summarized here and explained in greater detail in the following section e Special chip select features minimize power consumption by external memories e The Rabbit core operates at 1 8 V e The I O ring can operate 3 3 or 1 8 V e The main crystal oscillator may be divided by 2 4 6 or 8 e When the main crystal oscillator is divided by 4 6 or 8 the short chip select option is available e The 32 kHz oscillator may be used instead of the main oscillator this is sleepy mode The 32 kHz oscil lator may be divided by 2 4 8 or 16 this is ultra sleepy mode The self timed chip select option is avail able in both sleepy and ultra sleepy modes Before looking at the Rabbit 4000 low power features in greater detail please note that some of the power consumption in an embedded system is unaffected by the clever design features of the microprocessor As shown in the table below the current and thus power consumption of a microprocessor based system generally consists of a part that is independent of frequency and a part that depends on frequency Table 9 1 Factors affecting power consumption in the Rabbit 4000 microprocessor Current Consumption Current Consumption Independent of Frequency Dependent on Frequency Current leakage CMOS logic switching state Special circuits e g pull up resist
100. program up to the breakpoint The board has been programmed and Dynamic C is now in debug mode 14 If the programming cable is removed and the target board is reset the user s program will start running automatically because the BIOS will check the SMODE pins to determine whether to run the user application or enter the debug kernel 16 rabbit com How Dynamic C Cold Boots the Target System Semiconductor 5 Rabbit Memory Organization The architecture of earlier Rabbit processors was derived from the original Z80 microprocessor The origi nal Z80 instruction set used 16 bit addresses to address a 64 KB memory space All code and data had to fit in this 64 KB space To expand the available memory space the Rabbit 4000 adopts a scheme similar to that used by the Z180 The 64 KB space is divided into segments and the Rabbit s Memory Mapping Unit MMU maps each segment to a block in a larger memory The larger memory is 1 MB by default although the Rabbit 4000 allows this larger address space to be resized The segments are effectively windows to the larger memory The view from the window can be adjusted so that the window looks at different blocks in the larger mem ory Note also that the Rabbit 4000 has many new instructions that allow direct access to the larger mem ory space Figure 5 1 shows the memory mapping schematically NOTE Please see Technical Note 202 Rabbit Memory Management in a Nutshell for more details on
101. r inexperienced users The physical offset is measured from the beginning of the parent origin The logical address is required for origins of logical type that are declared relative to a physical origin and are optional otherwise It must be omitted if the declared origin is of physical type The exceptional origin types wcodorg and resvorg may be declared with logical offsets making them logical origins In the absence of logical offsets they will still be logical origins if declared as children of a logical origin The terminals start and end indicate the lower and upper boundaries of the parent origin respectively In the absence of a parent origin the extents are the physical addressable range defined by the MECR lt size gt The non terminal size is either the terminal symbol size followed by an integer or the symbol to fol lowed by an integer The integer following size specifies the number of bytes the origin contains The to terminal indicates where the origin ends in which case its size is the absolute value of the difference between the end and beginning of the origin Note that since origins can be defined in terms of their lower or upper boundaries to always specifies the complimentary boundary Rabbit 4000 Designer s Handbook rabbit com 43 6 5 1 4 Origin Declaration Start and End Syntax lt start gt The non terminal start is simply the terminal orgstart it must occ
102. ribed above and can also be configured so that the User block is mirrored and the System ID block is not If a version 5 ID block is configured so that only the User block is mirrored the images will be ID User A User B If Dynamic C does not find a System ID block on a device the compiler will assume that it is a BL1810 Jackrabbit board It is recommended that board designers include System ID blocks in their products with unused fields zeroed out to maximize future compatibility The System ID block has information about the location of the User block The User block is for storage of calibration constants and other persistent data the user wishes to keep in flash It is strongly recommended that the User block using writeUserBlock or the Flash File System be used for storage of persis tent data Writing to arbitrary flash addresses at run time is possible using WriteFlash or WriteFlash2 but could lead to compatibility problems if the code were to be used on a different type of flash such as a huge non uniform sector size flash For example some flash types have a single sector as big as 128K bytes at the bottom Writing to any part of the sector generally requires erasing the whole sector so a write to store data in that sector would have to save the contents of the whole sector in RAM modify the section to be changed and write the whole sector back This is obviously impractical Although Rabbit does not currentl
103. rmutation ce see see eke se Ge ke ee ee Re ee 11 OL PAI ZatlON iese esse GER ese Ee RA Ge ee a bee De 17 RAM available sesse ee ee Re RA Re EA 36 segment locations ees ese se ee se ee ee Re ke 32 MMIDR register i iese sees se se ee ee ee Re Re ee 32 MMU MIU iese see ES ees eke N be eke ees ee 15 N NUM FLASH WAITST ees sesse ese ese ee see ee ee 36 NUM RAM WAITST ee ees ese ee ee ee ee ee Re ee 36 O operating voltages esse sesse ee ee ee ee ee Reg 5 69 Origin directives iis sees EER GR esse KEER iieii ieke 37 MUSE dels AR RE EE 48 OSC EG OE OE N OE IE EN ID 3 4 7 75 Output enable oe ee cceeeesceeeeeteceeeeseeseeeseeseeeeensees 3 P Periodic interrupt iese ee RR EA Re AG 70 71 power CONSUMPTION esse ee Re RR 5 67 programming cable oases 1 3 13 15 16 76 programming cable connector ee 4 Q quadrant size iis ie ESE REGSE ESE NESER DER SENSE REDE gee eke 32 R RAM ACCESS ei AA AA AT RA EE 35 wrap around test iese ee ee Re RA Re 16 RAM SIZE EE EE ee ER Ee es 36 Realtek Ethernet Chip esse ees se ee ee Re 72 MOSEL AR EE EE EE DE 16 76 S SEGSIZE Tegistel s ccscescicsscseucsecectesstsesdsstesdevexstessiexis 32 Serial port EO hai el eee 3 sleepy mode enter and CXC Lice NE DEKKER RS ESE Ne SA GE ee 71 lu eiaal io EP N EO OE 71 SMODE Din 4 sesse Ee Se Ee ige Reeks Ke Be Eve gee seek ee 15 76 SBiepisier ss RE EE ee ee 32 STACKSEG register ese sesse ese ese se se ee ee e
104. rocessor core e recommended external 32 kHz crystal oscillator circuit Using the flash memory SST39LF020 45 4C WH and a self timed 106 ns chip select the memory con sumed 22 uA at 32 kHz and 1 4 pA at 2 kHz For a current list of supported flash please see Technical Note 226 Supported Flash Devices This document is available at http www rabbit com docs app tech notes shtml The supported flash devices will give approximately the same values as the flash device that was used for testing The processor core consumes between 3 and 50 uA at 3 3 V as the frequency is throttled from 2 kHz to 32 kHz and about 40 as much at 1 8 V The crystal oscillator circuit consumes 17 pA at 3 3 V This drops rapidly to about 2 uA at 1 8 V Additional power consumption in sleepy mode may come from a low power reset controller which may consume about 8 pA and CMOS leakage which may consume several uA The power consumed by CMOS leakage increases with higher temperatures NOTE Periodic interrupts are automatically disabled when the processor is placed in sleepy mode Debug is not directly supported in sleepy modes Please see Section 9 2 7 on page 72 for more information 70 rabbit com Low Power Design and Support 9 2 3 External 32 kHz Oscillator Unlike the Rabbit 2000 the Rabbit 4000 has no internal 32 kHz oscillator Instead there is a clock input The recommended external crystal oscillator circuit and the associated battery backup circu
105. rom 0xC0000 OxFFFFF and make it unavailable for xalloc You can then access this memory directly from your program as follows main long addr addr 0xc0000 pointto block reserved for my use Rabbit 4000 Designer s Handbook rabbit com 49 50 rabbit com The Rabbit BIOS Semiconductor 7 The System Identification and User Blocks The BIOS supports a System Identification block and a User block These blocks are placed at the top of the primary flash memory Identification information for each device can be placed in the System ID block for access by the BIOS flash driver and users This block contains specific part numbers for the flash and RAM devices installed the product s serial number Media Access Control MAC address if an Ethernet device and so on The earliest version of the System ID for Rabbit 4000 products is version 4 which is a mirrored images type When mirrored there are two combined ID User blocks images placed contiguously at the top of the pri mary flash from the top down as follows ID A User A ID B User B Ordinarily only one of the ID User blocks images is valid at a time and the valid ID User blocks image alternates between A and B at each call to the writeUserBlock function If both A and B images are simulta neously marked valid the A topmost image is taken to be correct Version 5 ID blocks can be config ured as desc
106. rsion is set to zero This function supports combined System ID User blocks sizes of sizeof SysIDBlock and from 4KB to 64KB inclusive in 4KB steps Prior versions of Dynamic C only supported mirrored combined block sizes of sizeof SysIDBlock 8KB 16KB and 24KB or unmirrored com bined System ID User blocks sizes of sizeof SysIDBlock and from 4KB to 32KB inclu sive in 4KB steps PARAMETER flash bitmap Bitmap of memory quadrants mapped to primary flash Examples 0x01 quadrant 0 only 0x03 quadrants 0 and 1 0x0C quadrants 2 and 3 RETURN VALUE 0 Successful 1 Error reading from flash 2 ID block missing 3 ID block invalid failed CRC check LIBRARY IDBLOCK LIB 54 rabbit com The System Identification and User Blocks 7 1 2 1 Determining the Existence of the System ID Block In Dynamic C versions prior to 7 20 and for ID block versions 1 and 2 the following sequence of events is used by readIDBlock to determine if an ID block is present l The 16 bytes at the top of the primary flash are read into a local buffer If a 256 KB flash is installed the 16 bytes starting at address 0x3FFF 0 will be read The last six bytes of the local buffer are checked for an alternating sequence of 0x55 OxAA 0x55 OxAA 0x55 OxAA If this is not found the block does not exist and an error 2 is returned 3 The ID block size SIZE is determined from the first 4 bytes of the 16 byte buffer 4
107. s iese ee Re Re ee ee ee ee ee ee ee ee ee ee ee 47 6 5 2 6 Origin Directive Examples cccceccescesscssseeceeseeeseeseceecesecesecsesecessecsaeeaeceeesseeeeseesenesaeeaes 48 6 5 2 7 Origin Directives in Program Code cceccesesssssseeeeeseeceesececeeseeseeeeeceenseeseesaesenenseeeees 48 6 5 2 8 Origin Directive to Reserve Blocks of Memory ees ee Re RA Re ee Re ee Re ee ee 49 Chapter 7 The System Identification and User BlockS iese se ee ee RA GR Re ee ee RA ee 51 T L System ID Block Details ESE ets RO EE ED De ee Gee N Rede Se pi has ei paddat dt be ee Le ER a ae EE 52 11 1 Definition of SysIDBlock vise is EE estes tated ei eels ee Eg Se ge Se a ae ee Reg Se deine See Ek 52 7 1 2 Reading the System ID Block oo ees ee se ee ee ee ee Re Re GR GR GR GR Ge GR AA Ge ee ee Re Re ek Re GR Re RR Ge 54 7 1 2 1 Determining the Existence of the System ID Block ese see ee ee Re GR GR ke ee 55 7 1 3 Writing the System ID Block ees ese ese ee ee ee ee Ge SA Ge Ke SA Ge Ge ee AA AR Ge Ge Pe Ge Ge ed ke Ke TRS 57 ae User Block Details risiet cei RE AE EE EE ER oan 57 12 1Baat Block ISSUES EE GR EE RE GE De EE ee ED Ea ER WE 57 rabbit com Table of Contents 7 2 2 Reserved MOE Ro US OE EE OO OE EE EE 58 7 2 3 Reading the User Block NE EE EN EE EE KO EE OE N 59 7 2 4 Writing the User SG SARA EE RE EE EE EE i 61 Chapter 8 BIOS Support for Program Cloning esse sesse sees ee Rd ee AR Ge AA AR Ee AE ge 63
108. sh memory attached to the processor this signal should have a frequency one eighth of the main crystal or oscillator frequency 11 2 Diagnostic Tests The cold boot mode may be used to communicate with the target system without using Dynamic C As dis cussed in Section 4 1 in cold boot mode triplets may be received by serial port A or the slave port To load and run the diagnostic programs the easiest method is to use the programming cable and a specialized ter minal emulator program over asynchronous serial port A To use the slave port requires more setup than the serial port method and it is not considered here Since each board design is unique it is not possible to give a one size fits all solution for diagnosing board problems However using the cold boot mode allows a high degree of flexibility Any sequence of triplets may be sent to the target 11 2 1 Program to Transmit Diagnostic Tests The file SerialIO_1 zip is available for download at www rabbit com support downloads downloads_prod shtml The zip file contains the specialized terminal emulator program serialIO exe and several diagnostic programs The diagnostic programs test a variety of functionality and allow the user to simulate some of the behavior of the Dynamic C download process Rabbit 4000 Designer s Handbook rabbit com 75 After extracting the files double click on serialIO exe to display the following screen a Serial 1 0 20010420 laf Help Ba
109. sical memory space A memory bank control register determines which memory chip is mapped into its quadrant how many wait states will be used for access ing that memory chip and whether the memory chip will be write protected MECR 8 bit register that determines the quadrant size and thus the size of the physical address space STACKSEG HIL 16 bit register that determines the location of the stack segment in the physical memory space DATASEG HIL 16 bit register that determines the location of the data segment in the physical memory space normally the location of the data variable space SEGSIZE 8 bit register holding two 4 bit values Together the values determine the relative sizes of the base seg ment data segment and stack segment in the 64 KB logical memory space MMIDR 8 bit register used to control separate I amp D space and to force CS1 to be always enabled or not Having CS1 always enabled reduces access time if CS1 is routed through an external battery backup device and the propagation delay through the external device may slow the transition of CS1 during memory cycles SP The SP register is the system stack pointer It is frequently changed by the user s code The BIOS sets up an initial value 6 1 2 Origins Dynamic C uses a mechanism known as an origin to define regions of memory for different purposes The BIOS declares several origins to tell the Dynamic C compiler where to place different types of code
110. t 0 0x000000 0x6000 The figure above shows that the segments of the 16 bit logical address space map to the physical address space The extended register set and additional 32 bit registers provided by the Rabbit 4000 make it easy to access the physical memory directly bypassing the logical to physical mapping and allowing linear access of up to 16 MB The size of the physical address space is determined by the quadrant size The quadrant size is determined by the MMU Expanded Code Register MECR This register contains the Bank Select Address setting The Bank Select Address represents the two most significant bits of the phys ical address that will be used to select amony the different quadrants By default the MECR selects A19 and A18 thus leaving 18 bits for the address which results in a quadrant size of 256 KB Table 5 1 shows the possible MECR values and the resulting quadrant sizes Rabbit 4000 Designer s Handbook rabbit com 19 Table 5 1 Selecting the Quadrant Size MECR Value eer ee arte Quadrant Size on cease 11100000b A18 A17 128 KB 512 KB 00000000b A19 A18 256 KB 1 MB default 00100000b A20 A19 512 KB 2 MB 01000000b A21 A20 1 MB 4MB 01100000b A22 A21 2 MB 8 MB 10000000b A23 A22 4 MB 16 MB One advantage of retaining the Rabbit 16 bit logical memory organization is that 16 bit addresses and pointers can reduce code size and execution times NOTE The relative size of the
111. t states are automatically inserted during the fetching of bytes 3 5 and 7 to wait for the serial or paral lel port ready The wait states continue indefinitely until the serial port is ready This will cause the proces sor to be in the middle of an instruction fetch until the next character is ready While the processor is in this state the chip select but not the output enable will be enabled if the memory mapping registers are such as to normally enable the chip select for the boot ROM address The chip select will stay low for extended periods while the processor is waiting for the serial or parallel port data to be ready 4 2 Program Loading Process Overview On start up Dynamic C first uses the PC s DTR line on the serial port to assert the Rabbit 4000 RESET line and put the processor in cold boot mode Next Dynamic C uses a four stage process to load a user pro gram 1 Load an initial loader cold loader to RAM via triplets sent at 2400 baud from the PC to a target in cold boot mode 2 Run the initial loader and load a secondary loader pilot BIOS to RAM at 57600 baud 3 Run the secondary loader and load the BIOS and user program to flash after compiling them to a file optionally negotiating with the Pilot BIOS to increase the baud rate to 115200 or higher so the loading can happen quickly 4 Run the BIOS Then run and debug the user program at the baud rate selected in Dynamic C NOTE Step 4 is combined with step 3 when
112. tem ID Block The WriteFlash function does not allow writing to the System ID block If the System ID block needs to be rewritten a utility to do so is available for download from the Rabbit website www rabbit com downloads files Write idblock zip or contact Rabbit s Technical Support 7 2 User Block Details Starting with the System ID block version 3 two contiguous copies of the combined ID User blocks are used or in the case of the version 5 ID block two contiguous copies of the User block are used Only one image contains valid data at any time When data is written to a mirrored User block the currently invalid User block image is updated first and then validated by changing its marker 5 byte from 0x00 to OxAA This marker is located in the user block itself in version 5 ID blocks where the mirrored user blocks are separate from the System ID Block and in version 5 and prior ID blocks where the User block and System ID blocks are combined the marker byte is located in the System ID Block Next the previ ously valid image is invalidated by changing its marker 5 byte from 0xAA to 0x00 Finally the newly invalidated image is updated In this way there is only a short period of time in which both images are marked valid and at no time are both data blocks marked invalid If a power failure occurs at any time dur ing the User block update the BIOS will still find a valid ID block and the valid User block will contain data from
113. tion options uint32 driversLoc offset to preloaded drivers start from ID block start positive is below ID block uint32 ioDescLoc offset to I O descriptions start from ID block start positive is below ID block uint32 iopermLoc offset to User mode I O permissions start from ID block start positive is below ID block uint32 persBlockLoc offset to persistent storage block area start from ID block start positive is below ID block uint16 userBlockSiz2 size of v 5 new style mirrored User block image uint16 idBlockCRC2 CRC of SysIDBlockType2 type with idBlockCRC2 member reset to zero and base CRC value of SysIDBlock idBlockCRC SysIDBlockType2 typedef struct int tableVersion version number for this table layout int productID Rabbit part int vendorID 1 Rabbit char timestamp 7 YY M D H M S long flashID Manufacturer ID Product ID 1st flash int flashType Write method int flashSize in 1000h pages int sectorSize size of flash sector in bytes int numSectors number of sectors int flashSpeed innanoseconds long flash2ID Manufacturer ID Product ID 2nd flash int flash2Type Write method 2nd flash int flash2Size in 1000h pages 2nd flash int sector2Size byte size of 2nd flash s sectors int num2Sectors number of sectors 52 rabbit com The System Identification and User Blocks int flash2Speed long ramID
114. to generate a known baud rate of 2400 bps e Install a crystal or oscillator for the main processor clock that is a multiple of 614 4 kHz or better a multiple of 1 8432 MHz e Do not use pin PB1 in your design if cloning is to be used e Be sure unused inputs are not floating As shown in Figure 1 1 the Rabbit programming cable connects a PC serial port to the programming con nector of the target system Dynamic C or the Rabbit Field Utility RFU runs as an application on the PC and can cold boot the Rabbit 4000 based target system with no pre existing program installed in the target A USB to RS232 converter may also be used instead of a PC serial port Rabbit 4000 based targets may also be programmed and debugged remotely over a local network or even the Internet using a RabbitLink card Rabbit 4000 Designer s Handbook rabbit com 1 Figure 1 1 The Rabbit 4000 Microprocessor and Dynamic C PC Hosts DynamicC Rappit Programming Rabbit Cable Microprocessor Level Conversion x PC Serial Programming Port Connector Dynamic C programming uses serial port A for software development However it is possible for the user s application to also use serial port A with the restriction that debugging is not available 2 rabbit com Introduction Semiconductor 2 Rabbit Hardware Design Overview Because of the glueless nature of the external interfaces especially the memory int
115. ud ma E rl rar DSR 2400 None 2 ic 1c2c3c4 F DIR FRITS Break CTS Transmit id Repeat File Tx Method TxMode bo f Za F N Bla Dnee CA All atOnce SE i er LF ei pb none Receive W Cycle Po RahMode Hex C ASCII Eed Click on Help at the top left hand side of the screen for directions for using this program A diagnostic program is a group of triplets You can open the provided diagnostic programs those files with the extension diag with Dynamic C or any simple text editor if you would like to examine the triplets that are sent to the target Also serialIO exe has the option of sending the triplets a line at a time so you can see the triplets in the one line window next to the Transmit button before they are sent NOTE Connecting the programming cable to the programming connector pulls both SMODE pins high On reset this allows a cold boot from asynchronous serial port A The reset may be applied by pushing the reset button on the target board or by checking then unchecking the box labeled DTR when using seriallIO exe In the following pages two diagnostic programs are looked at in some detail The first one is short and very simple a toggle of the status line Information regarding how to check the results of the diagnostic are given The second diagnostic program checks the processor RAM interface This example provides more detail in terms of how the triplets were derived After reading through these exampl
116. uffers in root memory This function is usually used as the inverse function of writeUserBlockArray PARAMETERS dests Pointer to array of destinations to copy data to numbytes Array of numbers of bytes to be written to each destination numdests Number of destinations addr Address offset in User block to read from RETURN VALUE 0 Success 1 Invalid address or range 2 No valid System ID block found block version 3 or later LIBRARY IDBLOCK LIB 60 rabbit com The System Identification and User Blocks 7 2 4 Writing the User Block writeUserBlock int writeUserBlock unsigned addr void source unsigned numbytes DESCRIPTION Rabbit based boards are released with System ID blocks located on the primary flash Version 2 and later of this ID block has a pointer to a User block that can be used for storing calibration con stants passwords and other non volatile data This block is protected from normal writes to the flash device and can only be accessed through this function This function writes a number of bytes from root memory to the User block NOTE Portions of the User block may be used by the BIOS for your board to store values such as calibration constants See the manual for your particular board for more information before overwriting any part of the User block Backwards Compatibility If the version of the System ID block doesn t support the User block or no System ID block is present then the 8 KB start
117. untered in the source code Except in small programs the bulk of the code in a program is executed using the extended memory xmem segment Code operates at the same speed whether addressed through the base segment or the xmem segment except that calling and returning from xmem functions takes a few extra clock cycles It just takes a few cycles longer to call xmem functions and return from them 5 2 2 1 Types of Code Best Suited for the Base Segment e Short subroutines of about 20 instructions or less that are called frequently will use less execution time if placed in root memory because of the faster calling linkage for 16 bit versus 20 bit addresses For a call and return 20 clocks are used compared to 32 clocks for xmem calls and returns This reduc tion in execution time becomes more significant when the call return sequence is a substantial portion of the total execution time e Interrupt routines Interrupt vectors use 16 bit addressing so the entry to an interrupt routine must be in the base segment e The BIOS core The initialization code of the BIOS must be at the start of the base segment e A function that modifies the XPC must always be executed from root memory 5 2 3 The Data Segment The data segment has a typical size of 28 KB starting at 24 KB 0x6000 above root code and ending at 52 KB OxCFFF The data segment is mapped to RAM and contains C variables Data allocation starts at or near the top and proceeds in a do
118. unused output to the unused inputs If pull up or pull down resis tors are required they should be made as large as possible if the circuit in question has a substantial part of its duty cycle with current flowing through the resistor 8 rabbit com Core Design and Components 3 3 Basic Memory Design Normally CSO and OEO and WEO should be connected to a flash memory that holds the startup code that executes at address zero When the processor exits reset with SMODE1 SMODEO set to 0 0 it will attempt to start executing instructions at the start of the memory connected to CS0 OEO and WEO For Dynamic C to work out of the box the basic RAM memory must be connected to CS1 OE1 and WEI CS1 has a special property that makes it the preferred chip select for battery backed RAM The BIOS defined macro CS1 ALWAYS ON may be redefined in the BIOS to 1 which will set a bit in the MMIDR register that forces CS1 to stay enabled low This capability can be used to counter a problem encoun tered when the chip select line is passed through a device that is used to place the chip in standby by rais ing CS1 when the power is switched over to battery backup The battery switchover device typically has a propagation delay that may be 20 ns or more This is enough to require the insertion of wait states for RAM access in some cases By forcing CS1 low the propagation delay is not a factor because the RAM will always be selected and will
119. ur exactly once and must occur before the end non terminal All origin declarations must follow this non terminal lt end gt The non terminal end is simply the terminal orgend must occur exactly once and must occur after the start non terminal When the compiler encounters this non terminal it locks the definitions of the origins and performs final collision detection All origin declarations must precede this non terminal 6 5 1 5 Origin Application Syntax lt orguse gt The orguse non terminal specifies which region the compiler should use for the origin type corresponding to name The name non terminal must be a previously declared origin All occurrences of orguse must fol low orgend lt action gt The action non terminal specifies what action the compiler should take for the named origin and may be the terminal apply or resume The apply terminal signifies resetting the memory region and should be used with care since the compiler may have already generated code or data to the origin The resume terminal signifies switching to the origin with its state preserved before a previous orguse refocused the compiler s attention 6 5 1 6 Origin Macro Declaration Syntax lt macdef gt The non terminal macdef is the terminal orgdef followed by the non terminal define and signifies a macro declaration based on an attribute of a previously declared origin Although the compiler does not force restrictions on where one may pl
120. using 4 K or greater sector flash 4 2 1 Program Loading Process Details When Dynamic C starts to compile a program the following sequence of events takes place 1 The serial port is opened at 2400 baud with the DTR line high and after a 500 ms delay the DTR line is lowered This pulses the reset line on the target low the programming cable inverts the DTR line placing the target into bootstrap mode 2 A group of triplets defined in the file COLDLOAD BIN consisting of 2 address bytes and a data byte are sent to the target The first few bytes sent are sent to I O addresses to set up the MMU and MIU and do system initialization The MMU is set up so that RAM is mapped to 0x00000 and flash is mapped to 0x80000 3 The remaining triplets place a small initial loader program at memory location 0x00000 The last triplet sent is 0x80 0x24 0x80 which tells the CPU to ignore the SMODE pins and start running code at address 0x00000 4 The initial loader measures the crystal speed to determine what divisor is needed to set a baud rate of 19200 The divisor is stored at address 0x3F02 for later use by the BIOS and the programming port is set to 57600 baud 5 The PC now bumps the baud rate on the serial port being used to 57600 baud Rabbit 4000 Designer s Handbook rabbit com 15 6 The initial loader then reads 7 bytes from the serial port First a 4 byte address field the physical address to place the secondary loader followed
121. w higher frequencies All of the divisors listed here were calculated with the default equation given on the next page Crystal 2400 9600 19200 57600 115200 230400 460800 Freq MHz baud baud baud baud baud baud baud 1 8432 23 5 2 0 a 3 6864 47 11 5 1 0 5 5296 71 17 8 2 7 3728 95 23 11 3 1 0 9 2160 119 29 14 4 11 0592 143 35 17 5 2 12 9024 167 41 20 6 14 7456 191 47 23 7 3 1 0 16 5888 215 53 26 8 18 4320 239 59 29 9 4 20 2752 b 65 32 10 22 1184 71 35 11 5 2 23 9616 77 38 12 25 8048 83 41 13 6 27 6480 89 44 14 29 4912 95 47 15 7 3 1 36 8640 119 59 19 9 4 44 2368 143 71 23 11 5 2 51 6096 i 167 83 21 13 6 58 9824 191 95 31 15 7 3 Baud rate is not available at given frequency Baud rate is available with further BIOS modification Rabbit 4000 Designer s Handbook rabbit com The default equation for the divisor is _ CPU frequency in Hz visor EE ET ETE If the divisor is not an integer value that baud rate is not available for that frequency identified by a in the table If the divisor is above 255 that baud rate is not available without further BIOS modification identified by a in the table To allow that baud rate you need to clock the desired serial port via timer A1 by default they run off the peripheral cloc
122. we also need root code for the segmented addressing the Rabbit provides The line above defines the rootcode origin to be a child of the xmemcode region This is legal because root code addresses can also be used for xmem code all root addresses have a corresponding physical address The origin starts at the beginning of xmemcode but notice the addition of log 0 for logi cal 0 The origin type for rootcode is rcodorg a logical origin This means that rootcode can be accessed through logical addresses so the compiler needs to know where it is situated in logical memory i e the origin needs a starting logical address In this case it starts at logical address 0 orgdef rvarorg rootdata in ram above start log ROOTCODE SIZE size ROOTDATA SIZE The origin named rootdata is a child of ram and as such inherits the property of being battery backed The origin starts at the beginning of ram and has size ROOTDATA_SIZE It is a logical origin its starting logical address is ROOTCODE_SIZE a macro defined in the BIOS orgdef wcodorg watcode in rootdata below end size WATCHCODESIZE The origin named watcode is a child of rootdata and as such is also of logical origin type Its starting logical address is not explicitly stated but can be determined from the parent origin logical extents Fol lowing the inheritance below end indicates that the origin should be at
123. wnward direction It is also possible to place executable code in the data segment if it is copied from flash to the data segment This can be desirable for code that is self modifying code to implement debugging aids or code that controls writes to the flash memory In separate I amp D space the data segment is twice as big 54 KB but code cannot be executed from it 5 2 4 The Stack Segment Usually the stack segment is assigned to the range of logical addresses 0xD000 to OxDFFF It is always mapped to RAM and holds the system stack Multiple stacks may be implemented by defining them in the 4 KB space by remapping the 4 KB space to different locations in physical RAM memory or by using both approaches Multiple stack allocation is handled by uC OS II internally For example if sixteen 1 KB stacks are needed then four stacks can be placed in each 4 KB mapping and four different mappings for the window can be used Rabbit 4000 Designer s Handbook rabbit com 21 5 2 5 The Extended Memory Segment This 8 KB segment from logical address 0xE000 to OxFFFF is a sliding window into extended code and it can also be used by routines that manipulate data located in extended memory The xmem window uses up only 8 KB of the 16 bit addressing space While executing code the mapping is shifted by 4 KB each time the code passes the halfway point in the 8 KB xmem window The halfway point corresponds to the root address 0xF000 or 60KB On all Rabbit pr
124. y sell products with this type of flash there is no guarantee that future flash market conditions won t require that such flash types be used Other board designers may have to deal with the same flash market issues The User block is imple mented in a way that preserves forward binary compatibility with a wide range of flash devices Rabbit 4000 Designer s Handbook rabbit com 51 7 1 System ID Block Details The BIOS will read the System ID block during startup If the BIOS does not find an ID block it sets all fields to zero in the data structure SysIDBlock The user may access the information contained in the System ID block by accessing SysIDBlock 7 1 1 Definition of SysIDBlock The following global data structures are defined in IDBLOCK LIB and are loaded from the flash device during BIOS startup Users can access this struct in RAM if they need information from it The reserved field will expand and or shrink to compensate for the change in size Items marked are essential for proper functioning of the System ID block and certain features e g TCP IP needs the hea address Items marked are desirable for future compatibility typedef struct SysIDBlockType2 uint8a flashMBC Memory Bank Configurations uints flash2MBC uints ramMBC uint32 devSpecLoc Count of additional memory devices immediately preceding this block uint32 macrosLoc Start of the macro table for additional board configura

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