ICS PCI-AOB2 Series, User Manual

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Programming 5-3
* Although it is possible to write the low and high bytes separately as shown above, it is
much easier to write both bytes with a single OUT DX, AX instruction. In that case, only
even addresses are written. In any case, DACs 2 and 3 only exist on the PCI-AOB4/6 and
DACs 4 and 5 only exist on the PCI-AOB6.
Table 5-2. I/O Address Map for the Digital I/O
The Digital I/O Control Byte sets the directions of Port A and Port B.
Table 5-3. Digital I/O Control Byte Values
Table 5-4. DAC Data Format
Address Write * Read
Base + E not used Restrict-Output-Voltage (Limits outputs to
15% of full scale range).
Base + F not used Clear Restrict-Output-Voltage (Allows full
operating output voltage).
Address Write Read
Base + 20 Digital I/O Port A, Output Digital I/O Port A, Input
Base + 21 Digital I/O Port B, Output Digital I/O Port B, Input
Base + 22 not used not used
Base + 23 Digital I/O Control Byte not used
Port B Input Port B Output
Port A Input 92h 90h
Port A Output 82h 80h
BIT D7 D6 D5 D4 D3 D2 D1 D0
Low Byte B7 B6 B5 B4 B3 B2 B1 B0
High Byte x x x x B11 B10 B9 B8