Kontron KTA55-pITX - Manual (Page 21)

KTD-S0043-A Page 18 GPIO Interface
KTA55/pITX Software Guide
7.2 Linux Example
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/mman.h>
int main (void)
{
int
i;
int fd = open ("/dev/mem", O_RDWR); // open device "mem"
volatile unsigned char *ptr;
if (fd < 0) // is mem device present ?
{
printf ("\nCould not open memory device\n");
return -1;
}
// map 4k page to address 0xFED80000
ptr = (unsigned char*) mmap (NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0xFED80000);
if (ptr == MAP_FAILED) // did mapping failed ?
{
printf ("\nMapping failed\n");
close (fd);
return -1;
}
for (i = 0; i < 8; i++)
printf ("GPIO%d pin status: %0x02X\n", i, ((ptr[0x0100+i] & 0x80) >> 7)); // read and mask GPIO register
close (fd);
return 0;
}
Note: You must have administrator rights to execute this example. You can also use 'sudo' if you have no
administrator rights.