ICS Advent PCI-DIO32, User Manual

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3-6 PCI-DIO32 User’s Guide
Programming Examples
All examples assume a base address of 300 Hex.
Read inputs at port A :
Set Relay #3 on, write a “1” in bit position D3, to port address Base+3,
or 303 hex
:
Another method, which takes into account the read-back capability of
the output ports C and D:
Note: Reading back the ports (C and D) results in the binary complement of
the output.
MOV DX,300H ;Set DX to Port A
IN AL, DX ;Get Input Port Data
NOT AL ;Data read is negative logic
MOV DX, 303H ;Set DX to Port D
MOV AL, 00001000B ;Set bit 3 to a ‘1’
OUT DX, AL
MOV DX, 303H ;Set DX to Port D
IN AL, DX ;Get old port setting
NOT AL ; Invert input – see note below
OR AL,00001000B ;OR in bit 3
OUT DX, AL ;Set bit 3