D.3 assembly language samples, D.3.1 enable the dio input function, D.3.2 enable the dio output function – IEI Integration PICOe-HM650 User Manual

Page 167: Ssembly, Anguage, Amples

PICOe-HM650 Half-size PCIe CPU Card

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D.3 Assembly Language Samples

D.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

D.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