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DM6210 User`s Manual - RTD Embedded Technologies, Inc.

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1. IRQ Channel Select 000 Disabled 001 IRQ3 010 IRQ5 011 IRO9 100 IRQ10 101 IRQ11 110 IRQ12 111 IRQ15 IRQ Source Select 000 End of Convert 001 User TC Counter 0 out 010 User TC Counter 1 out 011 User TC Counter 2 out 100 External Clock 2 101 PO Latch Status 110 P1 Latch Status 111 Reserved This register is used to set the interrupt source and channel Reading this register returns the current settings End of Convert an interrupt is generated when the A D conversion is done User TC Counter 0 out an interrupt is generated when user TC Counter 0 s count reaches 0 User TC Counter 1 out an interrupt is generated when user TC Counter 1 5 count reaches 0 User TC Counter 2 out an interrupt is generated when user TC Counter 2 s count reaches 0 External Clock 2 an interrupt is generated when the external clock 2 CN3 45 line is pulsed PO Latch Status an interrupt is generated when data has been latched into Port 0 P1 Latch Status an interrupt is generated when data has been latched into Port 1 Software Selectable Interrupt Channel There are 7 software selectable interrupt channels which can be programmed in bits 3 through 5 of the Interrupt Register at BA 5 The interrupt output is driven by an open collector device which is turned off when the IRQ channel is set to disable At power up or reset this register is set to all zero s 6 3 Basic Programming F
2. sse 4 6 12 Digital Port 0 Read Write 8 bit sse nennen 4 7 BA 13 Digital I O Port 1 Read Write 8 6 2 4 7 14 Digital I O Strobe Select Read Write 8 61 sse 4 7 BA 15 Digital I O Control Read Write 8 61 4 8 Programming the DM210 2 1 uoo Med ce eb tree der Roe ee Ee e d 4 9 Clearing and Setting Bits in a Port eerte nennen nenne nennen o nennen treni nenne 4 9 CHAPTER 5 A D CONVERSIONS cresce eese e etes ee setas etos esto sese sets s seta ss toss 5 1 Selecting ar Channel uaa sa Rn 5 3 Startins an kn nie 5 3 Monitoring Conversion Status ota dee HERR HI bd erae e E Pa 5 3 Reading the Converted Data nidore Re em IR 5 4 Channel Scanning RAD etie pepe etg php ret MERE 5 5 CHAPTER 6 INTERRUPTS ense rens etna se tns seen sese tasto sete sesto sese toss tense sena ae 6 1 Software Selectable Interrupt Sources nnne ener nnn ener nennen 6 3 Software Selectable Interrupt 6 3 Basic Programming For Interrupt Handling 6 4 What Is n Interrupt n Ree te ce ed ieri en che RR een 6 4 Interrupt Request Lines ci ceto tfe D
3. 7 3 Module Accessories SOHO 1 4 Hardware Accessories den e 1 4 Optional Configurations 5 nme s 1 4 Using This Manual pedea dba E breite I r ERE ERROR i 4 When You Need Help ian epi Heo RR ee bo in i 4 CHAPTER 1 MODULE SETTINGS e eec e eee no cue ao rece ao anne socsstteeacesteeccesesecceseses 1 1 Factory Configured Switch and Jumper Settings 1 3 JP1 8254 Timer Counter Clock Sources Factory Settings CLK0 OSC CLK1 OT0 CLK2 OT1 1 4 P5 Analog Input Voltage Range Factory Setting 10 1 5 P6 Analog Input Voltage Polarity Factory Setting BIP Bipolar en 1 5 S1 Base Address Factory Setting 300 hex 768 1 2 2 1 6 JS3 JS4 JS5 and JS6 Pull up Pull down Resistors on Digital Lines se 1 7 Gx Resistor Configurable deo og eg edere p rese ep apetece fang ene o ER ERR ERR 1 8 CHAPTER 2 MODULE INSTALLATION 220000000000000000000000000000000000000000000000000000 teens e tease eoo 2 1 Module Installation ccc c om ea Dd d ON e ERR 2 3 External I O Connections eee genere tii eet eiie ere cb HR RSS 2 4 Connecting the Analog TMp ts nnne nr nn RE A nnns 2 4 Connecting the Timer Counters and Digit
4. DIGITAL VO This chapter explains the digital I O circuitry on DM6210 8 1 8 2 The DM6210 has 16 buffered TTL CMOS digital I O lines available for digital control applications These lines are grouped into four 4 bit ports Each 4 bit port can be programmed as input or output 12 Digital VO Port 0 Read Write 8 bit This port transfers the 8 bit Port 0 digital input output data between the module and external devices The bits are programmed as input or output in groups of 4 P0 0 PO 3 and P0 4 7 by writing to the Direction Register at BA 15 For all bits set as inputs a read reads the input values and a write is ignored For all bits set as outputs a read reads the last value sent out on the line and a write writes the current loaded value out to the line Note that when any reset of the computer is performed all digital lines are reset to inputs and their corresponding output registers are cleared 0 7 PO 6 P0 5 0 4 PO2 PO 13 Digital I O Port 1 Read Write 8 bit This port transfers the 8 bit Port 1 digital input output data between the module and external devices The bits are programmed as input or output in groups of 4 P1 0 P1 3 and P1 4 1 7 by writing to the Direction Register at BA 15 For all bits set as inputs a read reads the input values and a write is ignored For all bits set as outputs a read reads the last value sent out on the line and
5. The 8254 programmable interval timer provides three 16 bit 8 MHz timers for timing and counting functions such as frequency measurement event counting and interrupts All three of the Timer Counters are available for the user Figure 7 1 shows the TC circuitry 6210 1 0 CONNECTOR CN3 XTAL 8 MHz COUNTER CLK PIN 39 EXT CLK 0 0 5 V GATE PIN 19 EXT GATE 0 OUT PIN 40 OUT 0 TIMER PIN 43 EXT CLK 1 COUNTER CLK 5 V GATE PIN 41 EXT GATE 1 OUT PIN 42 T C OUT 1 COUNTER CLK ee EXT CLK 2 2 5 V i GATE PIN 46 EXT GATE 2 OUT PIN 44 4 T C OUT 2 Fig 7 1 User TC Circuitry Each timer counter has two inputs CLK in and GATE in and one output timer counter OUT They can be programmed as binary or BCD down counters by writing the appropriate data to the command word as described in the I O map discussion in Chapter 4 The output from from each Timer Counter is available at the connector CN3 The timers can be programmed to operate in one of six modes depending on your application The following paragraphs briefly describe each mode Mode 0 Event Counter Interrupt on Terminal Count This mode is typically used for event counting While the timer counter counts down the output is low and when the count is complete it goes high The output stays high until a new Mode 0 control word is written to the timer counter Mode 1 Hardware Retriggerable One Shot The output
6. ah en D ede e eiu 16 High level output voltage 2 4V min Low level output voltage 0 45V max High level input voltage 2 2V min 5 3V max Low level input voltage 0 3V min 0 8V max High level output current Isource 4 ma max Low level output current Isink oooooonnooncccnnnnnoccccccnnccacccccconananncncncnnnannncncnnnnns 8 ma max Timer Co nter eene irent CMOS 82C54 Three 16 bit down counters binary or BCD counting Programmable operating modes 6 Interrupt on terminal count programmable one shot rate generator square wave rate generator software triggered strobe hardware triggered strobe Counter input source sss External clock 8 MHz max or on board 8 MHz clock eee Available externally used as PC interrupts or cascaded to adjacent counter Counter gate External gate or always enabled Miscellaneous Inputs Outputs PC bus sourced 5 volts 12 volts if supplied by computer ground Current Requirements DM6210 240 mA 5 volts 1 2W Connector 50 pin right angle header Environmental Op
7. v save amp 171 outportb port address v save To set multiple bits in a port OR the current value of the port with the value b where b the sum of the individual bits to be set Note that the bits to be set do not have to be consecutive Example Set bits 3 5 and 7 in a port Read in the current value of the port OR it with 168 168 25 2 27 and then write the resulting value back to the port In assembly language this is programmed as mov al v save or al 168 mov dx PortAddress out dx al Often assigning a range of bits is a mixture of setting and clearing operations You can set or clear each bit individually or use a faster method of first clearing all the bits in the range then setting only those bits that must be set using the method shown above for setting multiple bits in a port The following example shows how this two step operation is done Example Assign bits 3 4 and 5 in a port to 101 bits 3 and 5 set bit 4 cleared First read in the port and clear bits 3 4 and 5 by ANDing them with 199 Then set bits 3 and 5 by ORing them with 40 and finally write the resulting value back to the port In C this is programmed as V Save v save amp 199 Vv Save v save 40 outportb port address v save A final note Don t be intimidated by the binary operators AND and OR and try to use operators for which you have a better intuition For instance if you are tempted to use addition and subtraction
8. O 1 7 Gx Resistor Configurable Gain The DM6210 has a resistor configurable gain circuitry Gx so that you can easily configure special gain settings for a specific application Note that when you use this feature all of the input channels will operate only at your custom gain setting Gx is derived by adding resistors R14 and R15 trimpot TR3 and capacitor C31 all located in the upper right area of the module The resistors and trimpot combine to set the gain as shown in the formula in Figure 1 7 Capacitor C31 is provided so that you can add low pass filtering in the gain circuit If your input signal is a slowly changing one and you do not need to measure it at a higher rate you may want to add a capacitor at C31 in order to reduce the input frequency range and in turn reduce the noise on your input signal The formula for setting the frequency is given in the diagram Figure 1 7 shows how the Gx circuitry is configured As shown in Figure 1 7 a solder short must be removed from the module to activate the Gx circuitry This short is located on the bottom side of the module labled JS2 Figure 1 8 shows the location of the solder short 1 8 To calculate Gx Gx TR3 R14 R15 1 To calculate frequency f 1 2 C31 R14 TR3 Fig 1 7 Gain Circuitry and Formulas for Calculating Gx and f Remove Solder Short from JS2 on Bottom Side of Module 00000000 00000 amp 00 0O000000000
9. is initially high and goes low on the clock pulse following a trigger to begin the one shot pulse The output remains low until the count reaches 0 and then goes high and remains high until the clock pulse after the next trigger Mode 2 Rate Generator This mode functions like a divide by N counter and is typically used to generate a real time clock interrupt The output is initially high and when the count decrements to 1 the output goes low for one clock pulse The output then goes high again the timer counter reloads the initial count and the process is repeated This sequence continues indefinitely 7 3 Mode 3 Square Wave Mode Similar to Mode 2 except for the duty cycle output this mode is typically used for baud rate generation The output is initially high and when the count decrements to one half its initial count the output goes low for the remainder of the count The timer counter reloads and the output goes high again This process repeats indefinitely Mode 4 Software Triggered Strobe The output is initially high When the initial count expires the output goes low for one clock pulse and then goes high again Counting is triggered by writing the initial count Mode 5 Hardware Triggered Strobe Retriggerable The output is initially high Counting is triggered by the rising edge of the gate input When the initial count has expired the output goes low for one clock pulse and then goes high again 7 4 CHAPTER 8
10. nte ptr eei idit 6 4 8259 Programmable Interrupt Controller 6 4 Interrupt Mask Register red ee o tidie 6 4 End of Interrupt EOI Command sse eterne msn ennen nennen 6 5 What Exactly Happens When an Interrupt Occurs 6 5 Using Interrupts in Your tpe ri teet dai 6 5 Writing an Interrupt Service Routine 5 6 5 Saving the Startup Interrupt Mask Register IMR and Interrupt Vector see 6 6 Restoring the Startup IMR and Interrupt 6 7 Common Interrupt Mistakes n rue aaa 6 7 CHAPTER 7 TIMER COUNTERS 2220000000200002200020000000000000000000020000000000000 0000000 tease sens sesta se n0n 7 1 CHAPTER 8 DIGITAL 4 eee eese eee eese ettet tn netta sesta se tos setas esten sesta sess stone 8 1 12 Digital Port 0 Read Write 8 bit 8 3 13 Digital I O Port 1 Read Write 8 bit 8 3 14 Digital Strobe Select Read Write 8 6 8 3 15 Digital I O Control Read Write 8 bit 8 4 Sttobing Data int Port 0 or Port lua e ERE ene p er es 8 4 CHAPTER 9 EXAMPLE PROGRAMS ecce esee eese eene seen etta seen na sense seen assess seta sets
11. procedures in your program and it can access global data If you are writing your first ISR we recommend that you stick to the basics just something that will convince you that it works such as incrementing a global variable NOTE If you are writing an ISR using assembly language you are responsible for pushing and popping registers and using IRET instead of RET There are a few cautions you must consider when writing your ISR The most important is do not use any DOS functions or routines that call DOS functions from within an ISR DOS is not reentrant that is DOS function cannot call itself In typical programming this will not happen because of the way DOS is written But what about when using interrupts Then you could have a situation such as this in your program If DOS function X is being executed when an interrupt occurs and the interrupt routine makes a call to DOS function X then function X is essentially being called while it is already active Such a reentrancy attempt spells disaster because DOS functions are not written to support it This is a complex concept and you do not need to understand it Just make sure that you do not call any DOS functions from within your ISR The one wrinkle is that unfortunately it 6 5 is not obvious which library routines included with your compiler use DOS functions rule of thumb is that routines which write to the screen or check the status of or read the keyboard and any disk I O ro
12. se tones tens sinus 9 1 C Programs iia t eo eter e m tette te soie aliti este 9 3 Quick Basic Programms AUR RR RR Eee OREL ER De ER HEIDE ae 9 3 CHAPTER 10 CALIBRATION 2200000000000000000220000200022000000000000000 seen esten asse tassa se tones to sese ense ease 10 1 Required Equipment ite rere et RPM ide pr pia ah a diete bea iret eres edet dn 10 3 A D Calibration ce toot m eH DER PIU 10 4 Unipolar Calibration Oed e BD e e RE IRE Ue e rt E PER ER Ten 10 5 Bipolar xe gap A eue pete a emit ee 10 5 APPENDIX A DM6210 SPECIFICATIONS 2 2u 02000002000000000000000000000002000000020000000 0000000000 1 APPENDIX B CN3 CONNECTOR PIN ASSIGNMENTS 1 APPENDIX COMPONENT DATA SHEETS 2 200s2000000000000000000200000000000000020000000000000000000000000 C 1 APPENDIX D WARRANTY s0ussrssosssonssnnssnnssnnsnnnsnonssonssnnsnnnssnnsnnnsnsnssonsnnnssnnssnnsnsnssonsssnssnnssnnnsnnne D 1 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 2 1 2 2 3 1 7 1 10 1 List of Illustrations Module Layout Showing Factory Configured Settings 1 3 8254 Timer Counter Clock Source Jumpers 7 1 4 8254 Timer Counter Circuit Block Diagram nennen 1 4 Analog Input Voltage Range and Polarity PS and sse 1 5 Base Address Switch 91 ara ala ra iui OON 1 6 Pull
13. trimpot TR2 until it flickers between the values listed in the table below Next set the voltage to 4 99634 volts and repeat the procedure this time adjusting TRI until the data flickers between the values in the table Data Values for Calibrating Bipolar Ranges Using 5 to 5 volts Offset TR2 Converter Gain TR1 Input Voltage 4 99878V Input Voltage 4 99634V 0000 0000 0000 1111 1111 1110 A D Converted Data 0000 0000 0001 1111 1111 1111 10 5 10 6 APPENDIX DM6210 SPECIFICATIONS 2 DM6210 Characteristics Typical 25 Interface Switch selectable base address I O mapped Software programmable interrupts Analog Input 16 single ended inputs Input impedance each channel gt 10 megohms Input ranges 5 10 0 to 10 volts Overvoltage protection EEES eN nnne 35 Settling tire coria 1 usec AID Converter 2 2 2 eene ei eus AD574 MI Ip Successive approximation Resolution er ie eis een 12 bits 2 44 mV 10V 4 88 mV 20V MITES 1 LSB typ Conversion Speed ents ae 20 usec typ Sample and hold acquisition time 5 usec typ Maximum throughput dasari ear 40 kHz Digital I O Number of lines lt i nee
14. up Pull down Resistors for the Digital 1 7 Gain Circuitry and Formulas for Calculating Gx and f sese 1 9 Diagram for Removal of Solder 1 1 9 CN3 VO Connector Pin Assignments uensssessesssersennnensennnennnennnnnennnenneennnnnennnnnnennneensnnnnsnen enne nenne 2 4 Analog Input Cotinections iii p rede et d e E p EHE ERES ea 2 5 DM6210 Block Diagram eese t tia 3 3 CAE CUIE tenete te bic tases 7 3 Module Layout ente e e e arc Pe Oc E eee E AER SERRE 10 3 iii INTRODUCTION The DM6210 dataModule medium speed analog input module turn your IBM PC compatible cpuModule or other PC 104 computer into a high performance data acquisition and control system Ultra compact for embedded and portable applications the DM6210 features 16 single ended analog input channels 12 bit 20 microsecond A D converter 5 10 or 0 to 10 volt analog input range Resistor configurable gain 16 TTL CMOS programmable digital I O lines Three independent 16 bit 8 MHz timer counters 5 volt only operation BASIC and C source code diagnostics program Analog to Digital Conversion The analog to digital A D circuitry receives up to 16 single ended analog inputs and converts these inputs into 12 bit digital data words which can then be read and or transferred to PC memory The analog input voltage range is jump
15. 0 high P0 4 P0 7 Port 1 low P1 0 P1 3 and Port 1 high P1 3 P1 7 each with 4 digital I O lines that can be set as input or output Resistors are connected to these lines and can be configured as either pull up or pull down resistors 10 k ohm pull up pull down resistors are installed on the module and a solder connection must be made on the bottom of the board to configure their operation The solder connections are made at JS3 for Port 0 low JS4 for Port 0 high JS5 for Port 1 low and JS6 for Port 1 high The factory default is pull up for all ports This is done by placing a solder short between the middle common pad and V 5 volts To configure the resistors as pull down resistors remove the existing solder connection and make one between the middle common pad and G ground To disable the pull up pull down resistor remove the solder connection WARNING Do not install a connection between all three pads as this will damage the board O ooooooon 00000800 000000 000000 0000000000000 amp 00000000 Solder Connections JS6 455 454 453 eee LIT LII eee G G G V G gBeogooooooooooooooog 0080000 amp Fig 1 6 Pull up Pull down Resistors for the Digital I
16. 000 amp ga 00000000 456 JSS JS4 JSS IT LII II ose G G 000000000000 O E agogo nogoooog Fig 1 8 Diagram for Removal of Solder Short 2 MODULE INSTALLATION The DM6210 is easy to install in your cpuModule or other PC 104 based system This chapter tells you step by step how to install and connect the module After you have installed the module and made all of your connections you can turn your system on and run the 6210DIAG diagnostics program included on your example software disk to verify that your module is working 2 1 2 2 Module Installation Keep the module in its antistatic bag until you are ready to install it in your cpuModule or other PC 104 based system When removing it from the bag hold the module at the edges and do not touch the components or connectors Before installing the module in your system check the jumper and switch settings Chapter 1 reviews the factory settings and how to change them If you need to change any settings refer to the appropriate instructions in Chapter 1 Note that incompatible jumper settings can result in unpredi
17. 1 7 by writing to the Direction Register at BA 15 For all bits set as inputs a read reads the input values and a write is ignored For all bits set as outputs a read reads the last value sent out on the line and a write writes the current loaded value out to the line Note that when any reset of the computer is performed all digital lines are reset to inputs and their corresponding output registers are cleared 1 7 P1 6 P1 5 P1 4 P1 3 P1 2 P1 1 P1 BA 14 Digital I O Strobe Select Read Write 8 bit This register is used to select the strobe source for the digital inputs when either Port 0 or Port 1 is programmed for latch mode Both Port 0 and Port 1 must use the same strobe signal Reading this register returns the current settings Port 0 amp 1 Latched Input Strobe Select 00 External Clock 0 CN3 39 01 External Clock 1 CN3 43 10 External Clock 2 CN3 45 11 reserved 15 Digital I O Control Read Write 8 bit This register is used to set the digital I O direction and enable the digital inputs to be latched Reading this register returns the current settings Port 1 Strobe Polarity 0 positive edge 1 negative edge Port 0 Strobe Polarity 0 positive edge Port 0 Low Direction P0 0 P0 3 0 input 1 output Port 0 High Direction P0 4 P0 7 1 negative edge Hs outpu Port 1 Latch Enable Port 1 Low Direction P1 0 P1 3 0 di
18. 70H IRQ9 uses vector 71H and so on Thus if the DM6210 will be using IRQ15 you should save the value of interrupt vector 77H 6 6 Before you install your ISR temporarily mask out the IRQ you will be using This prevents the IRQ from requesting an interrupt while you are installing and initializing your ISR To mask the IRQ read in the current IMR at port 21H IRQO IRQ7 or at I O port AIH IRQ8 IRQIS and set the bit that corresponds to your IRQ remember setting a bit disables interrupts on that IRQ while clearing a bit enables them The IMR on 8259 is arranged so that bit 0 is for IRQO bit 1 is for IRQ1 and so on The IMR on 8259B is arranged so that bit 0 is for IRQ8 bit 1 is for IRQ9 and so on See the paragraph entitled Interrupt Mask Register IMR earlier in this chapter for help in determining your IRQ s bit After setting the bit write the new value to I O port 21H IRQO IRQ7 or I O port AIH IRQ8 IRQ15 With the startup IMR saved and the interrupts on your IRQ temporarily disabled you can assign the interrupt vector to point to your ISR Again you can overwrite the appropriate entry in the vector table with a direct memory write but this is a bad practice Instead use either DOS function 25H set interrupt vector or if your compiler provides it the library routine for setting an interrupt vector Remember that vectors 8 15 are for IRQO IRQ7 and vectors 70H 77H are for IRQ8 IRQIS If you need to program
19. Counter Clock Sources Factory Settings CLK0 OSC CLK1 OT0 CLK2 OT1 This header connector shown in Figure 1 2 lets you select the clock sources for the 8254 timer counters and TC2 The factory setting cascades all three timer counters with the clock source for being the on board 8 MHz oscillator the output of TCO providing the clock for TC1 and the output of TC1 providing the clock for TC2 You can connect any or all of the sources to an external clock input through the CN3 I O connector or you can set TCI and TC2 to be clocked by the 8 MHz oscillator Figure 1 3 shows a block diagram of the timer counter circuitry to help you with these connections NOTE When installing jumpers on this header make sure that only one jumper is installed in each group of two or three CLK pins CLK1 CLKO CLK2 JP1 Fig 1 2 8254 Timer Counter Clock Source Jumpers JP1 TIMER COUNTER TIMER COUNTER 1 TIMER COUNTER 2 CLK CLK GATE OUT CLK 8 MHz 45V 45V 6210 1 0 CONNECTOR CN3 1 l 1 PIN 391 EXT CLK 0 PIN 19 b EXT GATE 0 PIN 40 T C OUT 0 PIN 43 EXT CLK 1 O PIN 41 4 EXT GATE 1 PIN 42 J T C OUT 1 PIN 45 EXT CLK 2 PIN 46 EXT GATE 2 PIN 44 A OUT 2 I I Fig 1 3 8254 Timer Counter Circuit Block Diagram 1 4 5 Analog Input Voltage Range Factory Setting 10 This header connector shown in Figure 1 4 lets you select the analog in
20. D conversion After making your initial channel selection you must allow for enough of a delay in your program for the selected channel to settle before starting the first A D conversion As soon as the first conversion is started you can then immediately select your next channel in the sequence Once the conversion is started the signal on the sampled channel has been locked in and you do not have to wait for an end of convert transition before programming the next channel Selecting the next channel as soon as the conversion of the previous channel is started ensures that enough time is allowed for the new channel to settle before the next conversion is started regardless of your PC type Except for the initial delay between the starting channel selection and first conversion you do not have to be concerned with building delays into your program and the accuracy of the conversions when following this program structure Note that the data you read will always be the data from the previously selected channel not the data from the currently selected channel 5 5 5 6 6 INTERRUPTS This chapter explains software selectable interrupts and basic interrupt programming techniques 6 1 6 2 Software Selectable Interrupt Sources The interrupt circuit on the DM6210 has 7 software selectable interrupt sources which can be pro grammed in bits 0 through 2 of the Interrupt Register at BA 5 as described and shown below
21. DM6210 User s Manual TIGO RTD Embedded Technologies Inc Real Time Devices Accessing the Analog World ISO9001 and AS9100 Certified ev DM6210 User s Manual RTD Embedded Technologies INC 103 Innovation Blvd State College PA 16803 0906 Phone 1 814 234 8087 FAX 1 814 234 5218 E mail sales rtd com techsupport rtd com web site http www rtd com Revision History Rev A New manual naming method Published by RTD Embedded Technologies Inc 103 Innovation Blvd State College PA 16803 0906 Copyright 1999 2002 2003 by RTD Embedded Technologies Inc All rights reserved Printed in U S A The RTD Logo is a registered trademark of RTD Embedded Technologies cpuModule and utilityModule are trademarks of RTD Embedded Technologies PhoenixPICO and PheonixPICO BIOS are trademarks of Phoenix Technologies Ltd PS 2 PC XT PC AT and IBM are trademarks of International Business Machines Inc MS DOS Windows Windows 95 Windows 98 and Windows NT are trademarks of Microsoft Corp PC 104 is a registered trademark of PC 104 Consortium All other trademarks appearing in this document are the property of their respective owners Table of Contents INTRODUCTION 1 1 Analog to Digital Conversion 1 3 8254 Tinier Counter NA i 3 iia 1 3 What Comes With Your Module
22. F ACCIDENT MISUSE ABUSE such as use of incorrect input voltages improper or insufficient ventilation failure to follow the operating instructions that are provided by RTD Embedded Technologies acts of God or other contingencies beyond the control of RTD Embedded Technologies OR ASA RESULT OF SERVICE OR MODIFICATION BY ANYONE OTHER THAN RTD Embedded Technologies EXCEPT AS EXPRESSLY SET FORTH ABOVE NO OTHER WARRANTIES AREEX PRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MER CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Embedded Technologies EXPRESSLY DISCLAIMS ALL WARRANTIES NOT STATED HEREIN ALLIMPLIED WARRANTIES INCLUDING IMPLIED WARRANTIES FOR MECHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE LIMITED TO THE DURATION OF THIS WARRANTY IN THE EVENT THE PRODUCTIS NOT FREEFROM DEFECTS AS WARRANTED ABOVE THE PURCHASER S SOLE REMEDY SHALL BE REPAIROR REPLACEMENT AS PROVIDED ABOVE UNDERNO CIRCUMSTANCES WILL RTD Embed ded Technologies BELIABLE TO THE PURCHASER OR ANY USER FOR ANY DAMAGES INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES EXPENSES LOST PROFITS LOST SAVINGS OR OTHER DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PRODUCT SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSE QUENTIAL DAMAGES FOR CONSUMER PRODUCTS AND SOME STATES DO NOT ALLOW LIMITA TIONS ON HOW LONG AN IMPLIED WARRANTY LASTS SO THE ABOVE LIMITATIONS OR EXCLU SIO
23. NS MAY NOT APPLY TO YOU THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS AND YOU MAY ALSOHAVE OTHER RIGHTS WHICH VARY FROM STATE TOSTATE D 3 RTD Embedded Technologies Inc 103 Innovation Blvd State College PA 16803 0906 USA Our website www rtd com DM6210 User Settings Base I O Address m
24. NTROL 5 VOLTS WV Fig 3 1 DM6210 Block Diagram A D Conversion Circuitry The DM6210 performs analog to digital conversions on up to 16 analog input channels The following paragraphs describe the A D circuitry Analog Inputs Sixteen single ended analog input channels are available on the DM6210 The analog input range is jumper selectable for 5 to 5 volts 10 to 10 volts or 0 to 10 volts with 35 Vdc overvoltage protection The channels are connected to a sample and hold amplifier through a multiplexing circuit The active channel is selected through software as described in Chapter 4 The S H amplifier captures and holds the input signal at a constant level while the conversion is per formed ensuring that dynamic analog signals are accurately digitized This capacitive circuit quickly charges to a level corresponding to the input voltage being sampled and holds the charge for the duration of the conversion A D Converter The 12 bit A D converter when combined with the typical acquisition time of the sample and hold circuitry provides a throughput rate of up to 40 000 samples per second The A D output is a 12 bit data word 3 3 Timer Counters An 8254 programmable interval timer provides three 16 bit 8 MHz timer counters to support a wide range of timing and counting functions These timer counters can be cascaded or used individually for many applications Each timer counter has two inputs CLK in and GATE
25. a write writes the current loaded value out to the line Note that when any reset of the computer is performed all digital lines are reset to inputs and their corresponding output registers are cleared als pe eje P1 7 P1 6 P1 5 P1 4 P1 3 P1 2 P1 1 P1 1 BA 14 Digital I O Strobe Select Read Write 8 bit This register is used to select the strobe source for the digital inputs when either Port 0 or Port 1 is programmed for latch mode Both Port 0 and Port 1 must use the same strobe signal Reading this register returns the current settings Port 0 amp 1 Latched Input Strobe Select 00 External Clock 0 CN3 39 01 External Clock 1 CN3 43 10 External Clock 2 CN3 45 11 reserved 15 Digital I O Control Read Write 8 bit This register is used to set the digital I O direction and enable the digital inputs to be latched Reading this register returns the current settings Port 1 Strobe Polarity 0 positive edge 1 negative edge Port 0 Low Direction P0 0 P0 3 0 input 1 output Port 0 Strobe Polarity 0 positive edge Port 0 High Direction P0 4 PO 7 1 negative edge 0 input 1 output Port 1 Latch Enable Port 1 Low Direction P1 0 P1 3 0 disabled 0 input 1 enabled 1 output PortO Latch Enable 44 High Direction P14 4 P4 7 0 disabled D input 1 enabled 1 output Bit 0 Sets the direction of the Port 0 0 Port 0 3 digital lin
26. al 2 4 Running the 6210DIAG Diagnostics enne enne eterne nennen 2 4 CHAPTER 3 HARDWARE DESCRIPTION 2000000000000022000000200000022000002 2000000020000 sese etas etes sesto 3 1 A D Conversion 3 3 Analog Input i 3 3 A D Co a n 3 3 TIME ct a dd atrio 3 4 Digital IO 3 ire dta aee ere ERE 3 4 3 4 CHAPTER 4 MODULE OPERATION AND PROGRAMMING cesse eee en esee ea sese eae eco 4 1 Defining the VO Map voices kn PC PE genaues len 4 3 BA 0 Read A D Data Start Convert Read Write 16 6 ener 4 3 BATI Reserved od Re eR e Re ODORE INE 4 3 BA 2 Read Board ID LSB Read Only 8 bit essere 4 3 BA 3 Read Board ID MSB Read Only 8 bit esses eene 4 3 BA 4 Channel Select Read Write 8 bit sss 4 3 5 IRQ Select Read Write 8 61 essere enne 4 4 BA 6 Read Status Clear IRQ Read Write 8 bit nennen nennen nennen 4 4 BA 7 Reserved i Rep RE mue inei ta 4 6 8 8254 Timer Counter 0 Read Write 8 bit sssssssssesseseeeeee eene enne eene 4 6 9 8254 Timer Counter 1 Read Write 8 bit eene enne ener 4 6 10 8254 Timer Counter 2 Read Write 8 61 sse 4 6 11 8254 Control Word Write Only 8 bit
27. ascal examples show what the shell of your ISR should be like In C void interrupt ISR void Your code goes here Do not use any DOS functions outportb 0x20 0x20 Send EOI command to 8259A for all IROs outportb 0x20 0xA0 Send EOI command to 8259B if using IRQ8 Jos In Pascal Procedure ISR Interrupt begin Your code goes here Do not use any DOS functions Port 20 20 Send EOI command to 8259A for all IRQs Port SAO 20 Send EOI command to 8259B if using IRQ8 T5 1 end Saving the Startup Interrupt Mask Register IMR and Interrupt Vector The next step after writing the ISR is to save the startup state of the interrupt mask register and the interrupt vector that you will be using The IMR for IRQO IRQ7 is located at I O port 21H the IMR for IRQ8 IRQIS is located at I O port The interrupt vector you will be using is located in the interrupt vector table which is simply an array of 256 four byte pointers and is located in the first 1024 bytes of memory Segment 0 Offset 0 You can read this value directly but it is a better practice to use DOS function 35H get interrupt vector Most and Pascal compilers provide a library routine for reading the value of a vector The vectors for IRQO IRQ7 are vectors 8 through 15 where IRQO uses vector 8 uses vector 9 and so on The vectors for IRQ8 IRQ15 are vectors 70H through 77H where IRQ8 uses vector
28. below shows you how to read from and write to I O ports using some popular programming languages Read 8 Bits Write 8 Bits Read 16 Bits Write16 Bits Data inporb Address outportb Address Data Data inport Address outport Address Data Turbo Pascal Data Port Address Port Address Data Data PortW Address PortW Address Data In addition to being able to read write the I O ports on the DM6210 you must be able to perform a variety of operations that you might not normally use in your programming The table below shows you some of the operators discussed in this section with an example of how each is used with C Pascal and BASIC Note that the modulus operator is used to retrieve the least significant byte LSB of a two byte word and the integer division operator is used to retrieve the most significant byte MSB amp a b c a b c a b amp c a b c Pascal MOD DIV AND OR a b MOD c a bDIVc a b AND a bORc Many compilers have functions that can read write either 8 or 16 bits from to an I O port For example Turbo Pascal uses Port for 8 bit port operations and PortW for 16 bits Turbo C uses inportb for an 8 bit read of a port and inport for a 16 bit read Be sure to use the correct operation for each register on the DM6210 Clearing and Setting Bits in a Port When you clear or set one or more bits in a port you must be careful that you do not change the status of the other bits You can preserv
29. ched End of Convert Status 0 converting 1 not converting 0 interrupt 1 interrupt PO Latch Status 0 Data is not latched 1 Data is latched Starting with bit 0 these status bits show Bit 0 Shows the status of the A D converter Bit 1 Shows when an interrupt has occurred Bit 2 Shows when data has been latched at the Port 0 digital inputs Bit 3 Shows when data has been latched at the Port 1 digital inputs Bit 4 Reserved Bit 5 Reserved Bit 6 Reserved Bit 7 Reserved 4 5 7 Reserved 8 8254 TC Counter 0 Read Write 8 bit This address is used to read write the 8254 TC Counter 0 A read shows the count in the counter and a write loads the counter with a new value Counting begins as soon as the count is loaded 9 8254 TC Counter 1 Read Write 8 bit This address is used to read write the 8254 TC Counter 1 A read shows the count in the counter and a write loads the counter with a new value Counting begins as soon as the count is loaded BA 10 8254 TC Counter 2 Read Write 8 bit This address is used to read write the 8254 TC Counter 2 A read shows the count in the counter and a write loads the counter with a new value Counting begins as soon as the count is loaded BA 11 8254 Control Word Write Only 8 bit This address is used to write to the control register for the 8254 The control word is defined below and detailed in th
30. cluded on the module Installation procedures are given at the end of Chapter 1 Module Settings What Comes With Your Module You receive the following items in your DM6210 package DM6210 interface module with stackthrough bus header Mounting hardware Software and diagnostics diskette with example programs in BASIC and C source code User s manual If any item is missing or damaged please call Real Time Devices Customer Service Department at 814 234 8087 If you require service outside the U S contact your local distributor Module Accessories In addition to the items included in your module package Real Time Devices offers a full line of software and hardware accessories Call your local distributor or our main office for more information about these accessories and for help in choosing the best items to support your module s application Hardware Accessories Hardware accessories for the DM6210 include the TMX32 analog input expansion board with thermo couple compensation which can expand a single input channel on your DM6210 to 16 differential or 32 single ended input channels the OP series optoisolated digital input boards the MR series mechanical relay output boards the OR16 optoisolated digital input mechanical relay output board the USF4 universal sensor interface with sensor excitation the TS16 thermocouple sensor board the TB50 terminal board and XB50 prototype terminal board for easy signal access and pr
31. ctable module operation and erratic response The DM6210 comes with stackthrough connectors for CN1 and CN2 Pins B10 and C19 are keying pins and will be plugged on the top of the board and removed from the bottom NOTE The DM6210 module will only work with an AT cpuModule Do not try to use it with an XT cpuModule To install the module follow the procedures described in the computer manual and the steps below 1 Turn OFF the power to your system 2 Touch a metal rack to discharge any static buildup and then remove the module from its antistatic bag 3 Use the appropriate standoffs for your application to secure the module when you install it in your system 4 Holding the module by its edges orient it so that the bus connector s pin 1 lines up with pin 1 of the expansion connector onto which you are installing the module 5 After carefully positioning the module so that the pins are lined up and resting on the expansion connector gently and evenly press down on the module until it is secured on the connector NOTE Do not force the module onto the connector If the module does not readily press into place remove it and try again Wiggling the module or exerting too much pressure can result in damage to the DM6210 or to the mating module 6 After the module is installed connect the cable to I O connector CN3 on the module When making this connection note that there is no keying to guide you in orientation You must make
32. d to as 8259B To use interrupts you need to know how to read and set the 8259 interrupt mask registers IMR and how to send the end of interrupt EOI command to the 82595 Interrupt Mask Registers IMR Each bit in the interrupt mask register IMR contains the mask status of an IRQ line in 8259A bit 0 is for IRQO bit 1 is for IRQ1 and so on while in 8259B bit 0 is for IRQ8 bit 1 is for IRQ9 and so on If a bit is set equal to 1 then the corresponding IRQ is masked and it will not generate an interrupt If a bit is clear equal to 0 then the corresponding IRQ is unmasked and can generate interrupts The IMR for IRQO IRQ7 is programmed through port 21H and the IMR IRQ8 IRQI5 is programmed through port wo e Jr mo a s ws Jr For all bits 0 IRQ unmasked enabled 1 IRQ masked disabled 6 4 End of Interrupt EOD Command After an interrupt service routine is complete the appropriate 8259 interrupt controller must be notified When using IRQO IRQ7 this is done by writing the value 20H to I O port 20H only when using 08 18015 you must write the value 20H to I O ports 20H and AOH What Exactly Happens When an Interrupt Occurs Understanding the sequence of events when an interrupt is triggered is necessary to properly write software interrupt handlers When an interrupt request line is driven high by a peripheral device such as the DM6210
33. digital input Program Port 0 digital output Digital I O Port O lines lines 12 Read Port 1 digital input Program Port 1 digital output Digital I O Port 1 lines lines BA 13 Program strobe select Digital I O Strobe Select Read strobe select register register BA 14 Digital I O Control Read control register Program control register 15 Base Address 4 3 0 Read A D Data Start Convert Read Write 16 bit A read provides the 12 bit converted data in the format below The data is left justified and is coded in a straight binary format Bit Bit E Bit E Bit El Bit Bit 12 11 10 9 8 7 6 5 4 3 2 1 A write at this address issues a Start Convert command software trigger The data written is irrelevant BA 1 Reserved BA 2 Read Board ID LSB Read Only 8 bit A read at this address returns the LSB of the board ID register The value returned should be hex 10 0 0 0 1 0 0 0 0 BA 3 Read Board ID MSB Read Only 8 bit A read at this address returns the MSB of the board ID register The value returned should be hex 62 m v os os m v 09 oo 0 1 1 0 0 0 1 0 BA 4 Channel Select Read Write 8 bit This register is used to set the analog input channel Reading this register returns the current settings 4 4 Analog Input Channel Select 0000 channel 1 0001 channel 2 0010 channel 3 0011 channel 4 0100 channel 5 0101 channel 6 0110 c
34. e data sheet included in Appendix C BCD Binary Counter Select 0 binary 00 Counter 0 1 BCD 01 Counter 1 10 Counter 2 Counter Mode Select 11 read back setting 000 Mode 0 event count 001 Mode 1 programmable 1 shot Read Load 010 Mode 2 rate generator 00 latching operation 011 Mode 3 square wave rate generator 01 read load LSB only 100 Mode 4 software triggered strobe 10 read load MSB only 101 Mode 5 hardware triggered strobe 11 read load LSB then MSB 4 6 12 Digital VO Port 0 Read Write 8 bit This port transfers the 8 bit Port 0 digital input output data between the module and external devices The bits are programmed as input or output in groups of 4 P0 0 P0 3 and P0 4 7 by writing to the Direction Register at BA 15 For all bits set as inputs a read reads the input values and a write is ignored For all bits set as outputs a read reads the last value sent out on the line and a write writes the current loaded value out to the line Note that when any reset of the computer is performed all digital lines are reset to inputs and their corresponding output registers are cleared P0 7 PO 6 5 0 4 P03 PO2 1 PO O 13 Digital I O Port 1 Read Write 8 bit This port transfers the 8 bit Port 1 digital input output data between the module and external devices The bits are programmed as input or output in groups of 4 P1 0 P1 3 and P1 4 P
35. e formulas for calculating voltage are shown below 5 volt range A D Value 2048 bits 10 volts 4096 bits input volts For example if the A D reading is 1024 the analog input voltage is calculated as follows 1024 2048 bits 2 4414 mV bit 2 5 volts 10 volt range A D Value 2048 bits 20 volts 4096 bits input volts For example if the A D reading is 1024 the analog input voltage is calculated as follows 1024 2048 bits 4 8828 mV bit 5 0 volts 0 to 10 volt range A D Value bits 10 volts 4096 bits input volts For example if the A D reading is 1024 the analog input voltage is calculated as follows 1024 bits 2 4414 mV bit 2 5 volts The key digital codes and their input voltage values are given in the following table 5 4 A D Converter Bit Weights Ideal Input Voltage millivolts A D Bit Weight 5 to 5 Volts 10 to 10 Volts seso 875000 650 968750 twe2w sme 9 6 7er 9094 _ 98 wow etess 99047 emo 956 u O 5000 00 10000 00 256 64 32 16 4 2 1 0 Channel Scanning If you want to sample a sequence of channels you can set up the DM6210 for channel scanning The main concern when you scan channels is that you allow enough settling time between the selection of the channel and the start of the A
36. e proper library is loaded when starting Quick Basic by typing QB L DRVR6210 These libraries were created using Borland C 3 1 and were generated from the file DRVR6210 C Should you need to recompile the libraries contact the factory for details on this procedure 9 3 9 4 CHAPTER 10 CALIBRATION This chapter tells you how to calibrate the DM6210 using the 6210DIAG calibration program included in the example software package and the three trimpots on the module These trimpots calibrate the A D converter gain and offset 10 1 10 2 This chapter tells you how to calibrate the A D converter gain offset The offset and full scale performance of the module s A D converter is factory calibrated Any time you suspect inaccurate readings you can check the accuracy of your conversions using the procedure below and make adjusts as necessary Using the 6210DIAG diagnostics program is a convenient way to monitor conversions while you calibrate the module Calibration is done with the module installed in your system You can access the trimpots at the edge of the module Power up the system and let the board circuitry stabilize for 15 minutes before you start calibrat ing Required Equipment The following equipment is required for calibration Precision Voltage Source 10 to 10 volts Small Screwdriver for trimpot adjustment While not required the 6210DIAG diagnostics program included with example software is helpful w
37. e the status of all bits you do not wish to change by proper use of the AND and OR binary operators Using AND and OR single or multiple bits can be easily cleared in one operation Note that most registers in the DM6210 cannot be read back therefore you must save the value in your program To clear a single bit in a port AND the current value of the port with the value b where b 255 2 Example Clear bit 5 in a port Read in the current value of the port AND it with 223 223 255 25 and then write the resulting value to the port In BASIC this is programmed as V SAVE V SAVE AND 223 OUT PortAddress V 4 9 To set a single bit in a port OR the current value of the port with the value b where b 2 Example Set bit 3 in a port Read in the current value of the port OR it with 8 8 23 and then write the resulting value to the port In Pascal this is programmed as V Save V_Save OR 8 Port PortAddress V Save Setting or clearing more than one bit at a time is accomplished just as easily To clear multiple bits in a port AND the current value of the port with the value b where b 255 the sum of the values of the bits to be cleared Note that the bits do not have to be consecutive Example Clear bits 2 4 and 6 in a port Read in the current value of the port AND it with 171 171 255 2 2 2 and then write the resulting value to the port In C this is programmed as v save
38. er selectable for bipolar ranges of 5 to 5 volts or 10 to 10 volts or a unipolar range of 0 to 10 volts The module is factory set for 5 to 5 volts Overvoltage protec tion to 35 volts is provided at the inputs A D conversions are performed by a 12 bit successive approxima tion converter This high performance converter and the high speed sample and hold amplifier preceding it make sure that dynamic input voltages are accurately digitized The resolution of a 12 bit conversion is 2 4414 millivolts on the 5 to 5 volt range and the maximum throughput is 40 000 samples per second The converted data is read and or transferred to PC memory one byte at a time through the PC data bus 8254 Timer Counter An 8254 programmable interval timer contains three 16 bit 8 MHz timer counters to support a wide range of timing and counting functions The clock gate and output pins for each of the three timer counters are available at the I O connector Digital I O The DM6210 has 16 TTL CMOS compatible digital I O lines which can be directly interfaced with external devices or signals to sense switch closures trigger digital events or activate solid state relays The lines can be programmed as inputs or outputs in groups of 4 bits There is also a special latched input mode which allows the digital inputs to be latched on an external clock edge for time critical applications Pads for installing and activating pull up or pull down resistors are in
39. erating temperature nn Oto 70 C Storage temperature 40 to 85 C HUM sii ie ieee ei ae Oto 90 non condensing Size 3 55 L x 3 775 W x 0 6 H 90mm x 96mm x 15mm A 3 4 APPENDIX CN3 CONNECTOR PIN ASSIGNMENTS 2 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 AIN7 AIN8 ANALOG GND EXT GATE 0 ANALOG GND P0 7 P0 6 P0 5 P0 4 P0 3 P0 2 P0 1 P0 0 EXT CLK 0 EXT GATE 1 EXT CLK 1 EXT CLK 2 12 VOLTS 12 VOLTS AIN9 AIN10 AIN11 AIN12 AIN13 AIN14 AIN15 AIN16 ANALOG GND PIN 1 ANALOG GND ANALOG GND P1 7 P1 6 P1 5 P1 4 P1 3 P1 2 P1 1 P1 0 T C OUT 0 T C OUT 1 T C OUT 2 EXT GATE 2 5 VOLTS PIN 49 DIGITAL GND CN3 Mating Connector Part Numbers Manufacturer Part Number 1 746094 0 3425 7650 B 3 4 C 1 APPENDIX C COMPONENT DATA SHEETS Intel 82C54 Programmable Interval Timer Data Sheet Reprint APPENDIX D WARRANTY AND RETURN POLICY Return Policy If you wish to return a product to the factory for service please follow this procedure Read the Limited Warranty to familiarize yourself with our warranty policy Contact the factory fora Return Merchandise Authorization RMA number Please have the following available Complete board name Board serial number A detailed description of the board s behavior List the name of a contac
40. es Bit 1 Sets the direction of the Port 0 4 Port 0 7 digital lines Bit 2 Sets the direction of the Port 1 0 Port 1 3 digital lines Bit 3 Sets the direction of the Port 1 4 Port 1 7 digital lines Bit 4 Enables latch mode for the Port 0 input lines When this mode is enabled data can be strobed and latched into Port 0 on either the rising edge or the falling edge of the strobe signal selected at 14 Bit 5 Enables latch mode for the Port input lines When this mode is enabled data be strobed and latched into Port on either the rising edge or the falling edge of the strobe signal selected at BA 14 Bit 6 Select Port 0 strobe polarity This bit has no meaning if latching is disabled Port 0 Bit 7 Select Port 1 strobe polarity This bit has no meaning if latching is disabled on Port 1 Strobing Data into Port 0 or Port 1 If you enable latch mode for either Port 0 or Port 1 data can be strobed into the respective port This means that data can be latched into the input latch and will remain at this value until another input strobe signal appears even if the input data changes The input strobe signal can be selected from 3 different sources specified at BA 14 Both Port 0 and Port use the same strobe signal The data can be latched on either the positive edge or the negative edge of the strobe This is set up by bits 6 and 7 at BA 15 Status bits at BA 6 can be monitored to show wh
41. ether data has been latched These status bits are cleared when the digital input port is read 8 4 CHAPTER 9 EXAMPLE PROGRAMS This chapter discusses the example programs included with the DM6210 9 1 9 2 Included with the DM6210 is a set of example programs that demonstrate the use of many of the module s features These examples are in written in C and BASIC Also included is an easy to use menu driven diagnostics program 6210DIAG which is especially helpful when you are first checking out your module after installa tion and when calibrating the module Before using the software included with your module make a backup copy of the disk You may make as many backups as you need C Programs These programs are source code files so that you can easily develop your own custom software for your DM6210 All of the programs use the files DRVR6210 C and PCUTILS C These files contain all of the routines for setting up the board and acquiring data DRVR6210 C contains all the functions needed to control the A D converter the Digital I O and the Timer Counters PCUTILS C contain functions to help program the CPU for interrupts Quick Basic Programs These programs are source code files so that you can easily develop your own custom software for your DM6210 All of the programs rely on the DRVR6210 LIB and the DRVR6210 QLB library files These library files contain all of functions needed to interface to the DM6210 Make sure th
42. for a better understanding of interrupt program development Writing an Interrupt Service Routine ISR The first step in adding interrupts to your software is to write the interrupt service routine ISR This is the routine that will automatically be executed each time an interrupt request occurs on the specified IRQ An ISR is different than standard routines that you write First on entrance the processor registers should be pushed onto the stack BEFORE you do anything else Second just before exiting your ISR you must write an end of interrupt command to the 8259 controller s Since 8259B generates a request on IRQ2 which is handled by 8259A an EOI must be sent to both 8259A and 8259B for IRQ8 IRQIS Finally when exiting the ISR in addition to popping all the registers you pushed on entrance you must use the IRET instruction and not a plain RET The IRET auto matically pops the flags CS and IP that were pushed when the interrupt was called If you find yourself intimidated by these requirements take heart Most Pascal and C compilers allow you to identify a procedure function as an interrupt type and will automatically add these instructions to your ISR with one important exception most compilers do not automatically add the end of interrupt command to the proce dure you must do this yourself Other than this and the few exceptions discussed below you can write your ISR just like any other routine It can call other functions and
43. hannel 7 0111 channel 8 1000 channel 9 1001 channel 10 1010 channel 11 1011 channel 12 1100 channel 13 1101 channel 14 1110 channel 15 1111 channel 16 5 IRQ Select Read Write 8 bit This register is used to set the interrupt source and channel Reading this register returns the current ERLE IRQ Channel Select IRQ Source Select 000 Disabled 000 End of Convert 001 001 User TC Counter 0 out 010 2 IRQ5 010 User TC Counter 1 out 011 IRQ9 011 User TC Counter 2 out 100 IRQ10 100 External Clock 2 101 IRQ11 101 PO Latch Status 110 IRQ12 110 P1 Latch Status 111 2 IRQ15 111 Reserved End of Convert an interrupt is generated when the A D conversion is done User TC Counter 0 out an interrupt is generated when user TC Counter 0 s count reaches 0 User TC Counter 1 out an interrupt is generated when user TC Counter 1 5 count reaches 0 User TC Counter 2 out an interrupt is generated when user TC Counter 2 s count reaches 0 External Clock 2 an interrupt is generated when the external clock 2 CN3 45 line is pulsed PO Latch Status an interrupt is generated when data has been latched into Port 0 Latch Status an interrupt is generated when data has been latched into Port 1 BA 6 Read Status Clear IRQ Read Write 8 bit A read provides the status bits defined below 1 Latch Status 0 Data is not latched IRQ Status 1 Data is lat
44. hen performing calibrations Figure 10 1 shows the module layout with the three trimpots used for calibration TRI TR2 and located along the top right edge a 200800000 I s 0000000000000 9o C25 00000000 5 R7 C12 El J DC1 U11 N s RN11 RN c8 TI 1 ORT ci 3 O Ofc TETIT ve RNG U2 Rs RN9 1 O000000000000808000 0 oog O O O O O O O O O O O O G G G O O O O eT 4 C9 2 o Fig 10 1 Module Layout 10 3 A D Calibration Two procedures are used to calibrate the A D converter for all input voltage ranges The first procedure calibrates the converter for the unipolar range 0 to 10 volts and the second procedure calibrates the bipolar ranges 5 10 volts Table 10 1 shows the ideal input voltage for each bit weight for all three input ranges Table 10 1 A D Converter Bit Weights AID Bit Weight ass lo swo oo 10 4 Unipolar Calibration Two adjustments are made to calibrate the A D converter for the unipolar range of 0 to 10 volts One is the offset adjustment and the other is the full scale or gain adjustment Trimpot TR4 is used to make the offset adjustment and trimpot 1 is used for gain adjustment This calibration procedure is performed with the module set up for a 0 to 10 volt input range Before making
45. in and one output timer counter OUT The clock sources for the timer counters can be selected using jumpers on header connector JP1 see Chapter 1 The timer counters can be programmed as binary or BCD down counters by writing the appropriate data to the command word as described in Chapter 4 The command word also lets you set up the mode of operation The six programmable modes are Mode 0 Event Counter Interrupt on Terminal Count Mode 1 Hardware Retriggerable One Shot Mode 2 Rate Generator Mode 3 Square Wave Mode Mode 4 Software Triggered Strobe Mode 5 Hardware Triggered Strobe Retriggerable These modes are detailed in the 8254 Data Sheet reprinted from Intel in Appendix C Digital I O The DM6210 has 16 TTL CMOS compatible digital I O lines which can be directly interfaced with external devices or signals to sense switch closures trigger digital events or activate solid state relays The lines can be programmed as inputs or outputs in groups of 4 bits There is also a special latched input mode which allows the digital inputs to be latched on an external clock edge for time critical applications Solder pads for activating pull up or pull down resistors are included on the module Interrupts The DM6210 has 7 software selectable interrupt sources end of convert 8254 timer counter output 0 8254 timer counter output 1 8254 timer counter output 2 external clock for timer counter 2 brought onto the module through CN3 Port 0
46. latch status and Port 1 latch status The end of convert signal can be used to interrupt the computer when an A D conversion is completed The 8254 timer counter outputs can be used to generate an end of count interrupt The external clock 2 interrupt can be used to generate interrupts at any desired interval from an external source The Port 0 and Port 1 latch status bits can be used to generate an interrupt when digital data has been strobed into the digital input latch 3 4 CHAPTER 4 MAPPING This chapter provides a complete description of the I O map for the DM6210 general programming information and how to set and clear bits in a port 4 1 4 2 Defining the I O The I O map for the DM6210 is shown in Table 4 1 below As shown the module occupies 16 consecu tive I O port locations The base address designated as BA can be selected using DIP switch S1 located on the edge of the module as described in Chapter 1 Module Settings This switch can be accessed without removing the module from the stack The following sections describe the register contents of each address used in the I O map Table 4 1 DM6210 I O Map Address Register Description Read Function Write Function Decimal Sen Conversion Read AD convened data stat conversion Baso Start Conversion Read A D converted data Start A D conversion 0 3 8254 Timer Counter Control Word Reserved Program counter mode BA 11 Read Port 0
47. ock sources for the 8254 Jumpers installed on CLKO OSC JP1 timer counters TCO TC2 CLK1 OTO 8 CLK2 OT1 cascaded P5 Sets the analog input voltage range P6 Sets the analog input voltage polarity Bl Sets the base address 300 hex 768 decimal Configures P0 0 PO 3 with pull up or pull down JS3 resistors Pull up Configures P0 4 PO 7 with pull up or pull down JS4 resistors Pull up Configures P1 0 P1 3 with pull up or pull down JS5 resistors Pull up Configures P1 4 P1 7 with pull up or pull down JS6 resistors Pull up TR1 TR2 TR coon tl H Or 3 g 0 O O 00 0 0 O O O O O 9 g g o o o o m 00000000 M200800000 m C21 Ss 80000000000000 am ys DC1 25 O0000000 U11 BE 080 5 des LH nm ado C 12 C13 f i C5 E z o E zm N TLL TES c8 DIT m 1 Okc TIIT US EIN NN RnB Eg HONOR 2 zm z Eis D T OA LC oo u u12 4 32 AUO000000000000000000000000000008 c1 En CHOOOO0O0O00000000000008 S 9 c 29000090000 dataModule M Fig 1 1 Module Layout Showing Factory Configured Settings 1 3 JP1 8254 Timer
48. or Interrupt Handling e What Is an Interrupt An interrupt is an event that causes the processor in your computer to temporarily halt its current process and execute another routine Upon completion of the new routine control is returned to the original routine at the point where its execution was interrupted Interrupts are very handy for dealing with asynchronous events events that occur at less than regular inter vals Keyboard activity is a good example your computer cannot predict when you might press a key and it would be a waste of processor time for it to do nothing while waiting for a keystroke to occur Thus the interrupt scheme is used and the processor proceeds with other tasks Then when a keystroke does occur the keyboard interrupts the processor and the processor gets the keyboard data places it in memory and then returns to what it was doing before it was interrupted Other common devices that use interrupts are modems disk drives and mice Your DM6210 board can interrupt the processor when a variety of conditions are met such as timer countdown finished end of convert and external clock By using these interrupts you can write software that effectively deals with real world events Interrupt Request Lines To allow different peripheral devices to generate interrupts on the same computer the AT bus has 16 differ ent interrupt request IRQ lines A transition from low to high on one of these lines generate
49. ototype development the DM16 adapter board for testing your module in a conventional desktop computer and 50 flat ribbon cable assembly for external interfacing Optional Configurations Other configurations of the DM6210 are available such as vertical connectors on some or all I O connec tors or a non stackthrough bus connector If you need an optional configuration for your requirements please consult the factory Using This Manual This manual is intended to help you install your new module and get it running quickly while also providing enough detail about the module and its functions so that you can enjoy maximum use of its features even in the most complex applications We assume that you already have an understanding of data acquisition principles and that you can customize the example software or write your own applications programs When You Need Help This manual and the example programs in the software package included with your module provide enough information to properly use all of the module s features If you have any problems installing or using this dataModule contact our Technical Support Department 814 234 8087 during regular business hours eastern standard time or eastern daylight time or send a FAX requesting assistance to 814 234 5218 When sending a FAX request please include your company s name and address your name your telephone number and a brief description of the problem You can also contact
50. put voltage range The range is set by placing the jumper across the pair of pins labeled 10V giving you a 10 volt range or by placing the jumper across the pins labeled 20V giving you a 20 volt range Note that when you place a jumper across 20V you must place the jumper on P6 across the BIP pins bipolar range of 10 to 10 volts The UNI setting on P6 cannot be used with 20V P6 Analog Input Voltage Polarity Factory Setting BIP Bipolar This header connector shown in Figure 1 4 lets you select the analog input polarity by placing a jumper across the pins labeled UNI for 0 to 10 volts or BIP for 5 or 10 volts Note that when you place a jumper across 20V on P5 you must place the P6 jumper across BIP 10 volts The UNI setting cannot be used with the 20 volt input range Figure 1 4 shows the three possible input voltage configurations for P5 and P6 c N c gt C lt 2 Z5 22 Z5 e 2 2 5 P5 5 I P5 Be P6 P6 P6 Fig 1 4a Fig 1 4b Inputs Connected Fig 1 4c Inputs Connected Factory Setting 5V for 10V for 0 to 10V Fig 1 4 Analog Input Voltage Range and Polarity P5 and P6 1 5 1 Base Address Factory Setting 300 hex 768 decimal One of the most common causes of failure when you are first trying your module is address contention Some of your computer s I O space is already occupied by internal I O and other peripherals When the DM6210 attempts
51. r each A D conversion The data written to start a conversion is irrelevant Monitoring Conversion Status The A D conversion status can be monitored through the end of convert EOC signal bit 0 at BA 6 This signal is low when a conversion is in progress and goes high when the conversion is completed This low to high transition can be used to generate an interrupt or you can poll this bit to see the status of the conversion End of Convert Status 0 converting P1 Latch Status 1 not converting 0 Data is not latched IRQ Status 1 Data is latched 0 no interrupt 1 interrupt PO Latch Status 0 Data is not latched 1 Data is latched 5 3 Reading the Converted Data The converted data is read from the register at BA 0 This is a 16 bit register with the A D data in the upper 12 bits The bottom 4 bits have no meaning and should be diregarded pe pales Palos eee ES EE se Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit 12 11 10 9 8 7 6 5 4 3 2 1 To convert the data to a voltage value you must scale the digital value properly First you must shift the data right 4 places This can be done by either using a shift right command or by dividing the value by 16 Once the data is shifted it must be multiplied by a scaling factor to convert the value to a voltage This scaling factor will change depending on the input range you have selected and the gain you have installed in the resistor configurable gain Th
52. s an interrupt request which is handled by one of the AT s two interrupt control chips One chip handles IRQO through IRQ7 and the other chip handles IRQ8 through IRQ15 The controller which handles IRQ8 IRQIS is chained to the first controller through the IRQ2 line When an IRQ line is brought high the interrupt controllers check to see if interrupts are to be acknowledged from that IRQ and if another interrupt is already in progress they decide if the new request should supersede the one in progress or if it has to wait until the one in progress is done This prioritizing allows an interrupt to be interrupted if the second request has a higher priority The priority level is determined by the number of the IRQ Because of the configuration of the two controllers with one chained to the other through IRQ2 the priority scheme is a little unusual IRQO has the highest priority IRQ1 is second highest then priority jumps to IRQ8 IRQ9 IRQ10 IRQ11 IRQ12 IRQ13 IRQ14 and IRQIS and then following IRQIS it jumps back to IRQ4 IRQ5 IRQ6 and finally the lowest priority IRQ7 This sequence makes sense if you consider that the controller that handles IRQ8 IRQ15 is routed through IRQ2 8259 Programmable Interrupt Controllers The chips responsible for handling interrupt requests in the PC are the 8259 Programmable Interrupt Control lers The 8259 that handles IRQO IRQ7 is referred to as 8259A and the 8259 that handles IRQ8 IRQIS is referre
53. sabled 0 input 1 enabled 1 output Porto Latch Enable 4 High Direction P1 4 P1 7 0 disabled S input 1 enabled 1 output Bit 0 Sets the direction of the Port 0 0 Port 0 3 digital lines Bit 1 Sets the direction of the Port 0 4 Port 0 7 digital lines Bit 2 Sets the direction of the Port 1 0 Port 1 3 digital lines Bit 3 Sets the direction of the Port 1 4 Port 1 7 digital lines Bit 4 Enables latch mode for the Port 0 input lines When this mode is enabled data can be strobed and latched into Port 0 on either the rising edge or the falling edge of the strobe signal selected at BA 14 Bit 5 Enables latch mode for the Port 1 input lines When this mode is enabled data can be strobed and latched into Port on either the rising edge or the falling edge of the strobe signal selected at BA 14 Bit 6 Select Port 0 strobe polarity This bit has no meaning if latching is disabled on Port 0 Bit 7 Select Port 1 strobe polarity This bit has no meaning if latching is disabled on Port 1 4 8 Programming the DM6210 This section gives you some general information about programming and the DM6210 The module is programmed by reading from and writing to the correct I O port locations These I O ports were defined in the previous section Most high level languages such as BASIC Pascal C and C and of course assembly language make it very easy to read write these ports The table
54. sure that pin 1 of the cable is connected to pin 1 of CN3 pin 1 is marked on the module with a small square For twisted pair cables pin 1 is the dark brown wire for standard single wire cables pin 1 is the red wire 7 Make sure all connections are secure 2 3 AIN1 AIN9 AIN2 AIN10 AIN3 AIN11 AIN4 AIN12 AIN5 AIN13 AIN6 AIN14 AIN7 AIN15 AIN8 AIN16 ANALOG GND ANALOG GND EXT GATE 0 ANALOG GND ANALOG GND ANALOG GND 0 7 1 7 P0 6 P1 6 P0 5 P1 5 P0 4 P1 4 P0 3 P1 3 P0 2 1 2 P0 1 P1 1 P0 0 P1 0 EXT CLK 0 T C OUT 0 EXT GATE 1 T C OUT 1 EXT CLK 1 T C OUT 2 EXT CLK 2 EXT GATE 2 12 VOLTS 5 VOLTS 12 VOLTS DIGITAL GND Fig 2 1 CN3 I O Connector Pin Assignments External I O Connections Figure 2 1 shows the DM6210 s CN3 I O connector pinout Refer to this diagram as you make your I O connections Note that the 12 and 12 volt signals are available at pins 47 and 49 only if your computer supplies these voltages Connecting the Analog Inputs NOTE It is good practice to connect all unused channels to ground as shown in the following diagram Failure to do so may affect the accuracy of your results Connect the high side of the analog input to of the analog input channels AIN1 through AIN16 and connect the low side to the corresponding dedicated ANALOG GND for the selected channel Figure 2 2 shows how these connections are made Connecting the Timer Counters and Digital I O For all of these connec
55. t person familiar with technical details of the problem or situation along with their phone and fax numbers address and e mail address if available List yourshipping address Indicate the shipping method you would like used to return the product to you We will not ship by next day service without your pre approval Carefully package the product using proper anti static packaging Write the RMA number in large 1 letters on the outside of the package Return the package to RTD Embedded Technologies Inc 103 Innovation Blvd State College PA 16803 0906 USA D 1 D2 LIMITED WARRANTY RTD Embedded Technologies Inc warrants the hardware and software products it manufactures and produces to be free from defects in materials and workmanship for one year following the date of shipment from RTD Embedded Technologies INC This warranty is limited to the original purchaser of product and is not transferable During the one year warranty period RTD Embedded Technologies will repair or replace at its option any defective products or parts at no additional charge provided that the product is returned shipping prepaid to RTD Embedded Technologies All replaced parts and products become the property of RTD Embedded Technologies Before returning any product for repair customers are required to contact the factory for an RMA number THIS LIMITED WARRANTY DOES NOT EXTEND TO ANY PRODUCTS WHICH HAVE BEEN DAM AGED AS A RESULT O
56. the interrupt controllers check to see if interrupts are enabled for that IRQ and then checks to see if other interrupts are active or requested and determine which interrupt has priority The interrupt controllers then interrupt the processor The current code segment CS instruction pointer IP and flags are pushed on the stack for storage and a new CS and IP are loaded from a table that exists in the lowest 1024 bytes of memory This table is referred to as the interrupt vector table and each entry is called an interrupt vector Once the new CS and IP are loaded from the interrupt vector table the processor begins executing the code located at CS IP When the interrupt routine is completed the CS IP and flags that were pushed on the stack when the interrupt occurred are now popped from the stack and execution resumes from the point where it was interrupted Using Interrupts in Your Programs Adding interrupts to your software is not as difficult as it may seem and what they add in terms of perfor mance is often worth the effort Note however that although it is not that hard to use interrupts the smallest mistake will often lead to a system hang that requires a reboot This can be both frustrating and time consuming But after a few tries you ll get the bugs worked out and enjoy the benefits of properly executed interrupts In addition to reading the following paragraphs study the example programs included on your DM6210 pro gram disk
57. the source of your interrupts do that next For example if you are using the program mable interval timer to generate interrupts you must program it to run in the proper mode and at the proper rate Finally clear the bit in the IMR for the IRQ you are using This enables interrupts on the IRQ Restoring the Startup IMR and Interrupt Vector Before exiting your program you must restore the interrupt mask register and interrupt vectors to the state they were in before your program started To restore the IMR write the value that was saved when your program started to I O port 21H for IRQO IRQ7 or I O port for IRQ8 IRQ15 Restore the interrupt vector that was saved at startup with either DOS function 25H set interrupt vector or use the library routine supplied with your compiler Performing these two steps will guarantee that the interrupt status of your computer is the same after running your program as it was before your program started running Common Interrupt Mistakes Remember that hardware interrupts are numbered 8 through 15 for IRQO IRQ7 and 70H through 77H for IRQ8 IRQIS The most common mistake when writing an ISR is forgetting to issue the EOI command to the appropriate 8259 interrupt controller before exiting the ISR Remember to clear the IRQ circuit on the DM6210 at BA 6 6 7 6 8 7 TIMER COUNTERS This chapter explains the 8254 timer counter circuits on the DM6210 7 1 7 2
58. these adjustments make sure that the jumpers on P5 and P6 are set for this range Use analog input channel gain 1 while calibrating the module Connect your precision voltage source to channel 1 Set the voltage source to 1 22070 millivolts start a conversion and read the resulting data Adjust trimpot TR4 until it flickers between the values listed in the table below Next set the voltage to 9 49829 volts and repeat the procedure this time adjusting TRI until the data flickers between the values in the table Data Values for Calibrating Unipolar Range 0 to 10 volts Offset TR4 Converter Gain TR1 Input Voltage 1 22070 mV Input Voltage 9 99634 V 0000 0000 0000 1111 1111 1110 A D Converted Data 0000 0000 0001 1111 1111 1111 Bipolar Calibration Two adjustments are made to calibrate the A D converter for the bipolar ranges of 5 and 10 volts One is the offset adjustment and the other is the full scale or gain adjustment Trimpot TR2 is used to make the offset adjustment and trimpot TRI is used for gain adjustment These adjustments are made with the module set for a range of 5 to 5 volts Before making these adjustments make sure that the jumpers on P5 and P6 are set for this range Use analog input channel 1 gain 1 while calibrating the module Connect your precision voltage source to channel Set the voltage source to 4 99878 volts start a conversion and read the resulting data Adjust
59. tions the high side of an external signal source or destination device is connected to the appropriate signal pin on the I O connector and the low side is connected to any DIGITAL GND Running the 6210DIAG Diagnostics Program Now that your module is ready to use you will want to try it out An easy to use menu driven diagnostics program 6210DIAG is included with your example software to help you verify your module s operation You can also use this program to make sure that your current base address setting does not contend with another device 2 4 CONNECTOR CN3 SIGNAL SOURCE 1 SIGNAL SOURCE 15 our Fig 2 2 Analog Input Connections 2 5 2 6 3 HARDWARE DESCRIPTION This chapter describes the features of the DM6210 hardware The major circuits are the A D the 8254 timer counters and the digital I O lines Module interrupts are also described in this chapter 3 1 3 2 The DM6210 has three major circuits the A D the timer counters and the digital I O lines Figure 3 1 shows the block diagram of the module This chapter describes hardware which makes up the major circuits DATA 16 ANALOG INPUTS 5 0 10 12 BIT RESISTOR CONFIG CONVERTER GAIN DIGITAL VO INTERRUPT SELECT PC BUS 1 0 CONNECTOR PULL UP DOWN RESISTORS TIMER COUNTER VO SELECT ECOLE 45 VOLTS DC DC 15 VOLTS CONTROL CONVERTER 12 VOLTS CO
60. to set and clear bits in place of the methods shown above DON T Addition and subtraction may seem logical but they will not work if you try to clear a bit that is already clear or set a bit that is already set For example you might think that to set bit 5 of a port you simply need to read in the port add 32 25 to that value and then write the resulting value back to the port This works fine if bit 5 is not already set But what happens when bit 5 is already set Bits 0 to 4 will be unaffected and we can t say for sure what happens to bits 6 and 7 but we can say for sure that bit 5 ends up cleared instead of being set A similar problem happens when you use subtraction to clear a bit in place of the method shown above CHAPTER 5 A D CONVERSIONS This chapter shows you how to program your DM6210 to perform A D conversions and read the results 5 1 5 2 The following paragraphs walk you through the programming steps for performing A D conversions In this discussion BA refers to the base address Selecting a Channel To select a conversion channel you must assign values to bits 0 through 3 in the Channel register at BA 4 Analog Input Channel Select 0000 channel 1 0001 channel 2 0010 channel 3 0011 channel 4 0100 channel 5 0101 channel6 0110 channel 7 0111 channel 8 Starting an A D Conversion A D conversions are started by writing to BA 0 A START CONVERT command must be issued fo
61. to use I O address locations already used by another device contention results and the module does not work To avoid this problem the DM6210 has an easily accessible DIP switch S1 which lets you select any one of 32 starting addresses in the computer s I O Should the factory setting of 300 hex 768 decimal be unsuit able for your system you can select a different base address simply by setting the switches to any one of the values listed in Table 1 2 The table shows the switch settings and their corresponding decimal and hexadeci mal in parentheses values Make sure that you verify the order of the switch numbers on the switch 1 through 5 before setting them When the switches are pulled forward they are OPEN or set to logic 1 as labeled on the DIP switch package When you set the base address for your module record the value in the table inside the back cover Figure 1 5 shows the DIP switch set for a base address of 300 hex 768 decimal Table 1 2 Base Address Switch Settings 1 Base Address Switch Setting Base Address Decimal Hex 5 432 1 Decimal Hex 54321 512 200 768 1 300 152 1 QF 1008 Gr 0 closed 1 open Fig 1 5 Base Address Switch S1 1 6 753 754 JSS and JS6 Pull up Pull down Resistors on Digital I O Lines The DM6210 has 16 TTL CMOS compatible digital I O lines which can be interfaced with external devices These lines are divided into four groups Port 0 low P0 0 P0 3 Port
62. us through our E mail address techsupport rtdusa com 1 MODULE SETTINGS The DM6210 has jumper and switch settings you can change if necessary for your application The module is factory config ured with the settings listed in Table 1 1 and shown on the mod ule diagram at the beginning of this chapter Should you need to change these settings use these easy to follow instructions before you install the module in your system By soldering jumpers in the desired locations in the associated pads as described near the end of the chapter you can configure the 16 digital I O lines to be pulled up or pulled down The final section describes how to install two resistors and a trimpot to set the resistor configurable gain to the value required for your application A pad for installing a capacitor is also in cluded in the gain circuitry for creating a low pass filter 1 1 1 2 Factory Configured Switch and Jumper Settings Table 1 1 lists the factory settings of the user configurable jumpers and switch on the DM6210 Fig ure 1 1 shows the module layout and the locations of the factory set jumpers The following paragraphs explain how to change the factory settings Pay special attention to the setting of S1 the base address switch to avoid address contention when you first use your module in your system Table 1 1 Factory Settings Switch Factory Settings Jumper Function Controlled Jumpers Installed Sets the cl
63. utines use DOS and should be avoided in your ISR The same problem of reentrancy exists for many floating point emulators as well meaning you may have to avoid floating point real math in your ISR Note that the problem of reentrancy exists no matter what programming language you are using Even if you are writing your ISR in assembly language DOS and many floating point emulators are not reentrant Of course there are ways around this problem such as those which involve checking to see if any DOS functions are currently active when your ISR is called but such solutions are well beyond the scope of this discussion The second major concern when writing your ISR is to make it as short as possible in terms of execution time Spending long periods of time in your ISR may mean that other important interrupts are being ignored Also if you spend too long in your ISR it may be called again before you have completed handling the first run This often leads to a hang that requires a reboot Your ISR should have this structure Push any processor registers used in your ISR Most C and Pascal interrupt routines automatically do this for you Put the body of your routine here ssue the EOI command to the 8259 interrupt controller by writing 20H to port 20H and port if you are using 8 15 Pop all registers pushed on entrance Most C and Pascal interrupt routines automatically do this for you The following C and P

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