IEI Technology WAFER-AL, User Manual

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WAFER-AL SBC
Page 118
The DIO connector on the WAFER-AL is interfaced to GPIO ports on the Super I/O
chipset. The DIO has both 8-bit digital inputs and 8-bit digital outputs. The digital inputs
and digital outputs are generally control signals that control the on/off circuit of external
devices or TTL devices. Data can be read or written to the selected address to enable the
DIO functions.
NOTE:
For further information, please refer to the datasheet for the Super I/O
chipset.
The BIOS interrupt call INT 15H controls the digital I/O.
INT 15H:
AH – 6FH
Sub-function:
AL – 8
:Set the digital port as INPUT
AL :Digital I/O input value
Assembly Language Sample 1
MOV AX, 6F08H ;setting the digital port as input
INT 15H ;
AL low byte = value