Appendix B Digital I/O; About Digital I/O; Digital I/O Programming - AXIOMTEK CAPA831 User Manual

About Digital I/O

The onboard 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.

Digital I/O Programming

Assembly sample code :
Set functionality:
;Start set DIO program:
mov dx,2Eh
mov al,87h
out dx,al
out dx,al
mov dx,2Eh
mov al,07h
out dx,al
mov dx,2Fh
mov al,08h
out dx,al
mov dx,2Eh
mov al,30h
out dx,al
mov dx,2Fh
mov al,02h
out dx,al
Digital I/O
®
CAPA831 Intel Atom
;Un-lock super I/O
TM
D2550/N2800/N2600 Processor 3.5" SBC
Appendix B
Digital I/O
Pin Signal
1 DI0 (Bit0)
3 DI1 (Bit1)
5 DI2 (Bit2)
7 GND
9 GND
CN5
Pin Signal
2 DO0 (Bit 3)
4 DO1 (Bit 4)
6 DO2 (Bit 5)
8 DO3 (Bit 6)
10 DO4 (Bit 7)
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