pwm.c

#include <pigpio.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
        //Holder for waiting on enter
        char s[3];

        //Number of arguments, first being program name
        if(argc != 4) {
                //We don't have all the data
                //Exit and tell user
                printf("Usage: ./%s 18 100000 50\n", argv[0]);
                printf("This would start a hardware PWM on pin 18 at 100000Hz with a duty cycle of 50%%\n);
        }

        //Start GPIO operations
        if(gpioInitialise() < 0) {
                printf("Failed to init gpio\n");
                return 1;
        }

        //First argument is pin
        int pin = atoi(argv[1]);

        //Second is frequency in hz
        int freq = atoi(argv[2]);

        //Third is percent of duty cycle
        float duty = 1000000.0/100.0*atof(argv[3]);

        //Start PWM
        if(gpioHardwarePWM(pin, freq, duty) < 0) {
                //If it doesn't work, end gpio operations
                gpioTerminate();
                //Tell the user
                printf("Failed to set hardware pwm on gpio pin %d\n", pin);
                //Exit
                return 1;
        }

        printf("Successfully started hardware PWM on pin %d at %dHz with a duty cycle of %s%%\n", pin, freq, argv[3]);
        printf("Press [ENTER] key to exit\n");

        //Waiting for [ENTER]
        fgets(s, 2, stdin);

        //Turn PWM off
        gpioPWM(pin, 0, 0);

        //End GPIO Operations
        gpioTerminate();

        return 0;
}