Intel iEi Motherboard A300 - Manual (Page 173)

A300 Motherboard
MOV DX, 320h Moves 320h into the DX data register for one of the GPIO
pins
MOV AL, ZZh Moves the user defined output data ZZh into the low bit
accumulator register AL
OUT DX, AL The ouput data in the low bit accumulator register AL is
transmitted out from the address stored in the DX data
register
B.2.3 General Purpose Input Procedure
The following instruction set is for a GPI procedure for one pin on the GPIO connector.
MOV DX, 320h Moves 320h into the DX data register for one of the GPIO
pins
IN AL, DX The input data in the low bit accumulator register AL is
transmitted to the address stored in the DX data register
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