Appendix B Digital I/O; B.1 About Digital I/O; B.2 Digital I/O Programming - AXIOMTEK CAPA318 User Manual

B.1 About Digital I/O

The onboard GPIO or digital I/O has 8 bits (DIO1~8). 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 where all of these pins
are set to 1.

B.2 Digital I/O Programming

Assembly sample code :
mov dx,fa18
mov al,00
out dx,al
mov dx,fa19
mov al,f0
out dx,al
mov dx,fa18
mov al,ff
out dx,al
mov dx,fa19
in al,dx
mov dx,fa18
mov al,1f
out dx,al
mov dx,fa19
mov al,40
out dx,al
in al,dx
Digital I/O
; Set DIO 0-7 to Output
; Set DIO 4-7 to High
; Set DIO 0-7 to Input
; Get DIO 0-7 status
; Set DIO 0-4 to Input, 5-7 to Output
; al = 1F => 00011111
; Set DIO 6 to High
; al = 40 => 01000000
; Get DIO 0-7 status
CAPA318 3.5" Board
Appendix B
Digital I/O
CN11
Pin Signal Pin
1 DO1 2
3 DI2 4
5 DO3 6
7 DI4 8
9 +5V 10
Signal
DI8
DO7
DI6
DO5
GND
65