AXIOMTEK CAPA322, User Manual

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CAPA322 3.5” Board
Digital I/O 57
Appendix B
Digital I/O
B.1 About Digital I/O
The onboard GPIO or digital I/O has 8 bits (DIO0~7). Each bit can be set to function as input or
output by software programming. In default, all pins are pulled high with +5V level (according
to main power). The BIOS default settings are 4 inputs and 4 outputs.
CN7
B.2 Digital I/O Programming
Assembly sample code :
mov dx,fa18 ; Set DIO 0-7 to Output
mov al,00
out dx,al
mov
dx,fa19 ; Set DIO 4-7 to High
mov al,f0
out dx,al
mov
dx,fa18 ; Set DIO 0-7 to Input
mov al,ff
out dx,al
mov
dx,fa19 ; Get DIO 0-7 status
in al,dx
mov
dx,fa18 ; Set DIO 0-4 to Input, 5-7 to Output
mov al,1f ; al = 1F => 00011111
out dx,al
mov
dx,fa19 ; Set DIO 6 to High
mov al,40 ; al = 40 => 01000000
out dx,al
in
al,dx ; Get DIO 0-7 status
Pin Signal Pin Signal
1 DI0 2 DO7
3 DI1 4 DO6
5 DI2 6 DO5
7 DI3 8 DO4
9 +5V 10 GND
1
10