C.3 assembly language samples, C.3.1 enable the dio input function, C.3.2 enable the dio output function – IEI Integration ECW-281B_D2550 User Manual
Page 155: Ssembly, Anguage, Amples
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ECW-281B-D2550 Embedded System
Page 141
C.3 Assembly Language Samples
C.3.1 Enable the DIO Input Function
The BIOS interrupt call INT 15H controls the digital I/O. An assembly program to enable
digital I/O input functions is listed below.
MOV AX,
6F08H
Sets the digital port as input
INT 15H Initiates the INT 15H BIOS call
C.3.2 Enable the DIO Output Function
The BIOS interrupt call INT 15H controls the digital I/O. An assembly program to enable
digital I/O output functions is listed below.
MOV AX,
6F09H
Sets the digital port as output
MOV BL,
09H
INT 15H Initiates the INT 15H BIOS call
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