Measurement-computing Daq PC-Card Instrukcja Użytkownika Pobierz pdf (Strona 50)

DaqBoards [ISA-Types Only] Daq* Hardware

3-20 Daq* Hardware

10-18-00

DaqBook / DaqBoard [ISA-types] / Daq PC-Card User’s Manual

DAC Reference Selection (JP2)

This 5×2 header (JP2) allows you to select internal or external voltage references for the two separate

analog outputs. If the internal -5 VDC reference is selected, either DAC can output from 0 to +5 VDC as

the register count varies from 0 to 4095 (12-bit). If an external voltage reference is desired (up to 10 VDC

in either polarity), the shunt jumpers must be set accordingly. There is also a provision to allow the

outputting of a simultaneous Sample-Hold command signal on the DAC1-REFIN pin with the DAC1 set up

for an internal reference.

&$87,21

The SSH setting cannot be used at the same time as a DAC1 external reference due

to a potentially damaging conflict on P1 pin #26. The defaults are both DAC0 and

DAC1 set to Internal Reference.

Note:

The SSH setting is used with DBKs: 2, 4, 5, 7, 17, 50, and 51. Refer to the DBK chapter (4)

as needed.

JP2 JP2 JP2

JP2

Factory Default

DAC0 External Ref

DAC1 External Ref

DAC0 External Ref

DAC1 Internal Ref

DAC0 Internal Ref

DAC1 External Ref

DAC0 Internal Ref

DAC1 Internal Ref

DAC0 External Ref

DAC1 Internal Ref

with SSH

DAC0 Internal Ref

DAC1 Internal Ref

with SSH

EXT

INT

SSH

INT

EXT

DAC1

DAC0

JP2

JP2 DAC Reference Settings

DMA and Interrupt Selection (JP8)

This 11×2 header (JP8) selects both the interrupt IRQ level and the Direct Memory Access (DMA) channel

for control of background data transfers. The preset default is DMA channel 5 and interrupt 10 (see figure).

•

Interrupt Selection. The DaqBoard may be set to interrupt the PC when certain hardware conditions

occur. The main board interrupt may be set to IRQ level 10, 11, 12, 14 or 15. The DaqBoard’s IRQ

level cannot be shared with any other device. Setting the JP8 interrupt jumper to OPEN can disable

interrupt assistance and background transfers.

•

DMA Selection. Direct Memory Access allows high-speed data transfer either from the ADC FIFO

or to the DAC FIFO. Only DMA channels 5-7 (of an ISA AT machine’s seven channels) are

available for the DaqBoard. Set both the DRQ and DACK jumpers to the desired DMA channel (the

DaqBoard does not share DMA channels). Set the DMA jumpers to OPEN when other devices use

DMA channels 5, 6 and 7.

JP8

DRQ7

DRQ6

DRQ5

IRQ15

IRQ14

IRQ12

IRQ11

IRQ10

DACK7

DACK6

DACK5

Factory Default

DMA Channel 5 and Interrupt 10

JP8

JP8JP8

DRQ7

DRQ6

DRQ5

IRQ15

IRQ14

IRQ12

IRQ11IRQ11

IRQ11

IRQ10

DACK7

DACK6

DACK5

2121

2222

DMA Channel 7 and Interrupt 12

Open DMA

Open Interrupt

JP8 DaqBoard DMA and Interrupt Selection

1 2 ... 45 46 47 48 49 50 51 52 53 54 55 ... 61 62

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