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Page 14

Operation of the Card

Page 14

01270146.doc

 Blue Chip Technology Ltd.

Timers

The AOP-12d includes an NEC µPD71054 timer chip which is equivalent to an
Intel 8254.

The timer chip contains three independent 16 bit counters which may be
operated in different modes.  There are five basic modes of operation with each
mode providing a different output signal from the three output pins of the
device.

IMPORTANT

Timers 0 and 1 are crucial to the operation of the board. The DAC
section is controlled by the output of these timers so for all operating
modes of the DAC, these timers must be configured to run. See the
section on TIMER INITIALISATION for code examples to configure
these timers.

The reference clock for timers 0 and 2 is 1Mhz.  Timer 1 is in series with the
output of timer 0.

Timer 0 is committed as the first divider for DMA in the AOP-12d and its
output is also available on the external connector.

Timer 2 is uncommitted in the AOP-12d and its output is available on the
external connector.

In DMA mode, timers 0 and 1 set the rate at which data is DMA’d. To set a
particular DMA rate, use the following equation:

Note that the 1 MHz clock is divided by 8 by the circuitry giving
a reference of 125 KHz

DMA RATE (in Hz) = 1250000 / divider

where “divider” = (65536 * TIMER 1 value) + (TIMER 0 value)

Содержание AOP-12D

Страница 1: ...AOP 12D Multi Function Analogue Output Card User Manual...

Страница 2: ......

Страница 3: ...ical photocopied recorded or otherwise without the prior permission in writing from the publisher For permission in the UK contact Blue Chip Technology Information offered in this manual is correct at...

Страница 4: ...nt Details 1 0 9 8 95 SH First approved issue new front sheet 2 0 20 12 95 EGW Addition of EMC information to Technical Section Errors corrected References to current outputs removed Added layout diag...

Страница 5: ...8 Fitting the Card 8 USING THE CARD 9 External Input Output Connections 9 Analogue Connections 9 Analogue Voltage Outputs 10 Digital Connections 11 OPERATION OF THE CARD 12 Programmable Digital Input...

Страница 6: ...ERING SYSTEMS 28 Binary and Hexadecimal Numbers 28 Base Address Selection 31 APPENDIX B PC MAPS 32 PC XT AT I O Address Map 32 PC XT Interrupt Map 33 PC AT Interrupt Map 34 DMA Channels 34 APPENDIX C...

Страница 7: ...and outputs and analogue outputs There are 24 TTL compatible programmable digital input outputs available externally There are also three programmable timers One of the timer outputs is available ext...

Страница 8: ...all O Ps Output Error Volts 0 5 of Span Output Settling Time 3 S to 1 LSB Data Transfer I O Port or DMA DMA Channels Supported 1 2 and 3 Fastest DMA Transfer Rate 12 S per Transfer Channel Selection...

Страница 9: ...nput Outputs Number of Channels 24 Digital Inputs High Level Input 2 2 Volts minimum Current 10 A sink Low Level Input 0 8 Volts maximum Current 10 A source Digital Outputs Logic High Voltage 3 5 Volt...

Страница 10: ...DMA transfer Timer 2 Uncommitted output available Timer 0 Resolution 1 S Minimum Time 2 S Maximum Time 130mS Timer 1 Resolution timer 0 output value Minimum Time 4 S Maximum Time 2 3 hours Timer 2 Res...

Страница 11: ...complied with regarding earthing and the installation of boards The board must be installed with the backplate securely screwed to the chassis of the computer to ensure good metal to metal i e earth...

Страница 12: ...end of the cable Failure to observe these recommendations may invalidate the EMC compliance Warning This is a Class A product In a domestic environment this product may cause radio interference in whi...

Страница 13: ...is included in the Appendices Base Address Select an unused I O address range for the card The card requires a block of 16 contiguous addresses The base address is set on jumper block JP3 Fitting a li...

Страница 14: ...setting of the DMA Acknowledge channels The settings must be the same on both JP2 and JP4 If DMA operation is not required the links may left open to allow the unused channels to be used by other card...

Страница 15: ...lowing table shows the pin out of the D type analogue connector CON1 The pins are arranged in three rows PIN USAGE PIN USAGE PIN USAGE 1 V output 1 18 No connect 34 V output 12 2 No connect 19 V outpu...

Страница 16: ...renced to these connections Measuring output voltages with reference to other ground points particularly the digital ground will give electrically noisy results The voltage output has a span from 10 V...

Страница 17: ...5 15 DIO port B bit 6 16 DIO port B bit 7 17 DIO port C bit 0 18 DIO port C bit 1 19 DIO port C bit 2 20 DIO port C bit 3 21 DIO port C bit 4 22 DIO port C bit 5 23 DIO port C bit 6 24 DIO port C bit...

Страница 18: ...appears to the PC as four ports The first three can be set as input or output by writing suitable codes to the fourth Control Port These four ports are mapped into the AOP 12d address map as follows...

Страница 19: ...t 81 129 Output Output Output Input 82 130 Output Input Output Output 83 131 Output Input Output Input 88 136 Output Output Input Output 89 137 Output Output Input Input 8A 138 Output Input Input Outp...

Страница 20: ...ing modes of the DAC these timers must be configured to run See the section on TIMER INITIALISATION for code examples to configure these timers The reference clock for timers 0 and 2 is 1Mhz Timer 1 i...

Страница 21: ...s are mapped into the AOP 12d address map as follows BASE 8 Timer Counter 0 read write 9 Timer Counter 1 read write 10 Timer Counter 2 read write 11 Control register write only Bits 6 and 7 in the con...

Страница 22: ...his writes 3 into the LOW 8 bits of the 16 bit counter register Output 0 to timer 0 count register base 8 This writes 0 into the HIGH 8 bits of the 16 bit counter register Output hex 78 to the timer c...

Страница 23: ...ister to load the required value The low 8 bits are sent first followed by the high 4 bits Output Value Output Voltage 0 10 V 2048 0 V 4095 10 V The DAC section operates in one of two basic modes I O...

Страница 24: ...e it is possible to output to all 12 channels by setting the AUTO CHANNEL SCANNING bit in channel enable register 2 When this bit is set after each DMA transfer the channel number will be incremented...

Страница 25: ...R W Timer Timer 0 count register 9 R W Timer Timer 1 count register 10 R W Timer Timer 2 count register 11 R W Timer Timer control register DAC Control Register Base 0 DATA BIT FUNCTION 0 DAC Channel...

Страница 26: ...t 1 0 Enable channel 2 output 1 Disable channel 2 output 2 0 Enable channel 3 output 1 Disable channel 3 output 3 0 Enable channel 4 output 1 Disable channel 4 output 4 0 Enable channel 5 output 1 Dis...

Страница 27: ...tput 3 0 Enable channel 12 output 1 Disable channel 12 output 4 0 Disable AUTOMATIC channel scanning 1 1 Enable AUTOMATIC channel scanning 5 0 Enable DMA Cycle mode 2 1 Disable DMA Cycle mode 6 Not Us...

Страница 28: ...amples EXAMPLE1 BAS EXAMPLE1 C These demonstrate the simple I O mode to output a single value to one analogue output channel EXAMPLE2 BAS EXAMPLE2 C These demonstrate reading and writing to the digita...

Страница 29: ...port map Available positions are shown in the IBM PC Technical Reference Guide However for those who do not possess a copy of this document a good place is the location normally allocated to the prot...

Страница 30: ...Ltd To set the base address to 300 Hex locate the jumper block JP3 labelled Base Address Set the following pattern on the links as indicated below with Connector CON2 on right hand side and the gold...

Страница 31: ...Interrupts The DAC generates an interrupt signal at the end of a DMA transfer The interrupt is selected on jumper block JP1 The diagram below shows the DAC set to produce an interrupt request on IRQ3...

Страница 32: ...ontrols which channel the DAC uses to request Direct Memory Access Only channels 1 2 and 3 are available Jumper JP2 sets the channel on which the DMA controller acknowledges the request It is essentia...

Страница 33: ...Detailed Card Installation Page 27 Blue Chip Technology Ltd 01270146 doc Page 27 Card Layout Diagram KFA12o Card Layout showing Selector Link Positions...

Страница 34: ...and HEXADECIMAL These two systems provide an alternative representation to decimal numbers For a binary number there are only 2 possible values 0 or 1 and as a result binary numbering is often known a...

Страница 35: ...1 1 1 1 8 1 0 0 1 0 1 2 1 9 1 0 0 1 1 1 3 2 0 1 0 1 0 0 1 4 Notice how the next higher column does not increment until the lesser one to its right has overflowed Binary representation is ideally suit...

Страница 36: ...forming a byte are divided into two groups of 4 bits known as NIBBLES With four bits there are 16 possible numeric combinations including zero A convenient method of representing each nibble is to use...

Страница 37: ...rds cover a range of addresses usually 16 Decimal Therefore the low order four bits are not included but two higher order bits are added This gives an address range of 0 to 3F0 Hex The following diagr...

Страница 38: ...Memory Mapper 0A0 0BF Interrupt Controller 2 8259 0F0 Clear NPX 80287 Busy 0F1 Reset NPX 80287 0F8 0FF Numeric Processor Extension 80287 1F0 1F8 Hard Disk Drive Controller 200 207 Reserved 278 27F Re...

Страница 39: ...doc Page 33 PC XT Interrupt Map Number Allocated to NMI Parity 0 Timer 1 Keyboard 2 Reserved 3 Asynchronous Communications Secondary SDLC Communications 4 Asynchronous Communications Primary SDLC Comm...

Страница 40: ...rd Output Buffer Full IRQ 2 Interrupt from CTLR 2 IRQ 8 Real time Clock Interrupt IRQ 9 S w Redirected to INT 0AH IRQ 2 IRQ 10 Reserved IRQ 11 Reserved IRQ 12 Reserved IRQ 13 Co processor IRQ 14 Fixed...

Страница 41: ...L 8237 or compatible devices each containing four channels The first one is used for byte transfers in the bottom 1 MB of system memory the second can transfer words into the bottom 16 MB Blue Chip Te...

Страница 42: ...A Channel 2 Current Address 0005H R W DMA Channel 2 Current Word Count 0006H R W DMA Channel 3 Current Address 0007H R W DMA Channel 3 Current Word Count 0008H R W Command Status Register 0009H R W DM...

Страница 43: ...6 MODE Bit 0 5 AUTO INC DEC 4 AUTO INIT 3 TRANS MODE Bit 1 2 TRANS MODE Bit 0 1 CHAN SEL Bit 1 0 CHAN SEL Bit 0 Mode Bits Bit1 Bit 0 FUNCTION 0 0 Demand Mode 0 1 Single Mode 1 0 Block Mode 1 1 Not Us...

Страница 44: ...NALOGUE OUT boards for outputting continuous wave forms Transfer Mode Bit 1 Bit 0 FUNCTION 0 0 Verify Transfer 0 1 Write Transfer 1 0 Read Transfer 1 1 Not Used Use WRITE TRANSFER if the I O board is...

Страница 45: ...a mask bit for a particular channel disables the DMA operation on that channel Status Register Port 0BH READ 7 CHAN 3 DMA RQ 6 CHAN 2 DMA RQ 5 CHAN 1 DMA RQ 4 CHAN 0 DMA RQ 3 CHAN 3 at TC 2 CHAN 2 at...

Страница 46: ...e physical memory address of the DMA transfer Addressing In order for DMA to operate correctly the page register and start address register should be set up to inform the DMA controller where in memor...

Страница 47: ...VARPTR dat In this example the variables seg and offs would contain the SEGMENT and OFFSET addresses of the array dat In order to pass this address to the DMA controller the segment and offset values...

Страница 48: ...e START address register for the DMA channel being used Load the length count into the TRANSFER LENGTH register Note that the DMA controller only transfers 8 bits at a time each value written to an AN...

Страница 49: ...2060 OFFSET seg 2070 OFFSET OFFSET 16 2080 OFFSET OFFSET offs 2090 OFFSET OFFSET AND 65535 2100 REM Setup the DMA registers 2105 OUT HA 7 REM DISABLE DMA CHANNEL 3 2110 OUT HC 0 REM RESET BYTE SELECT...

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