#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <errno.h>
#include <string.h>
int main(void)
{
int channel=0;
fprintf(stderr, "press Ctrl-C to stop\n");
int fd = open("/dev/adc", O_RDWR);
if (fd < 0) {
perror("open ADC device:");
return 1;
}
for(;;) {
char buffer[30];
int len;
channel = (channel+1)%4;
buffer[0]=channel;
len = write(fd, buffer, 1);
if (len <=0)
perror("ADC write error\n");
len = read(fd, buffer, sizeof buffer -1);
if (len > 0) {
buffer[len] = '\0';
int value = -1;
sscanf(buffer, "%d", &value);
printf("Channel:%d, ADC Value: %d\n", channel, value);
} else {
perror("read ADC device:");
return 1;
}
usleep(500* 1000);
}
close(fd);
}
