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c-gpio-intro/main.c

75 lines
1.4 KiB
C

// Christian Angelus 24/09/2026
// gpio command tool
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
//prototype functions
int gpio_export(const char *gpio);
int gpio_direction(int gpio, const char *direction);
int gpio_write(int gpio, int value);
int main (int argc, char *argv[]){
int fd;
char pin[] = "17";
gpio_export(pin);
//pin direction
fd = open("/sys/class/gpio/chip0/gpio17/direction", O_WRONLY);
if(fd<0)
{
perror("Error openng the GPIO export path");
return -1;
}
write(fd, "out",3);
close(fd);
//pin value
fd = open("/sys/class/gpio/chip0/gpio17/value", O_WRONLY);
if(fd<0)
{
perror("Error openng the GPIO export path");
return -1;
}
write(fd, "1",1);
close(fd);
//pin apagao
//unexport
fd = open("/sys/class/gpio/chip0/unexport", O_WRONLY);
if(fd<0)
{
perror("Error openng the GPIO export path");
return -1;
}
write(fd, "17",2);
close(fd);
printf("Hello from Rasperry Pi!\n");
printf("Number of arguments: %d\n", argc);
printf("Program is reciving: %s\n", argv[0]);
if(argc > 1)
printf("Argument: %s\n", argv[1]);
return 0;
}
//Complete functions
//
//gpio export
int gpio_export(const char *gpio){
int fd;
//export
fd = open("/sys/class/gpio/chip0/export", O_WRONLY);
if(fd<0){
perror("Error openng the GPIO path");
return -1;
}
write(fd,gpio, strlen(gpio));
close(fd);
return 0;
}