am335x -- led 控制

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
int main(void)
{

FILE *p=NULL;
 int i=0;
 p = fopen("/sys/class/gpio/export","w");
 fprintf(p,"%d",38);
 fclose(p);
 p =
fopen("/sys/class/gpio/gpio38/direction","w");
 fprintf(p,"out");
 fclose(p);
 for(i=0;i<100;i++)
 {
  p =
fopen("/sys/class/gpio/gpio38/value","w");
  fprintf(p,"%d",1);
  sleep(1);
  fclose(p);
  p =
fopen("/sys/class/gpio/gpio38/value","w");
  fprintf(p,"%d",0);
  sleep(1);
  fclose(p);
 }
 p = fopen("/sys/class/gpio/unexport","w");
 fprintf(p,"%d",38);
 fclose(p);
 return 0;
}