IEI Technology IMB-C2060, User Manual

Page: 159 / 172

IMB-C2060 microATX Motherboard
Page 145
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
C.3 Assembly Language Sample 1
MOV AX, 6F08H ;setting the digital port as input
INT 15H ;
AL low byte = value
AH – 6FH
Sub-function:
AL – 9
:Set the digital port as OUTPUT
BL :Digital I/O input value
C.4 Assembly Language Sample 2
MOV AX, 6F09H ;setting the digital port as output
MOV BL, 09H ;digital value is 09H
INT 15H ;
Digital Output is 1001b