ece_231_led_cl.c

// Josh Silva
// 33435438
// Lab4 part 6

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>

int main(int argc, const char *argv[])
{
    if (argc != 3)
    {
        printf("Usage:\n");
        printf("\tledCtl <led> <on/off>\n");
        printf("\n");
        printf("<led> : Number between 0-3\n");
        printf("<on/off>: 1 = on, 0 = off\n");
        return 1;
    }
    int ledNum = atoi(argv[1]);
    if (ledNum < 0 || ledNum > 3)
    {
        printf("<led> : Number between 0-3\n");
        return 1;
    }
    char ledPath[1024];
    sprintf(ledPath, "/sys/class/leds/beaglebone:green:usr%d/brightness",
    ledNum); int fid = open(ledPath, O_WRONLY);
    int onOff = atoi(argv[2]);
    switch (onOff)
    { case 0:
                    write(fid, "0", 1);
                    break;
        case 1:
                write(fid, "1", 1);
                break;
        default:
                printf("<on/off>: 1 = on, 0 = off\n");
                return 1;
    }
    close(fid);
    return 0;
}