Appendix B Digital I/O; B.1 About Digital I/O; B.2 How To Use Digital I/O - AXIOMTEK PICO512 User Manual

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 3 inputs and 5 outputs where all of these pins
are set to 1.

B.2 How to Use Digital I/O

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
PICO512 Pico-ITX Board
Appendix B
Digital I/O
CN7
Pin Signal Pin
1 DIO0(Bit 0) 2
3 DIO1(Bit 1) 4
5 DIO2(Bit 2) 6
7 DIO3(Bit 3) 8
9 +5V 10
Signal
DIO4(Bit 4)
DIO5(Bit 5)
DIO6(Bit 6)
DIO7(Bit 7)
GND
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