Intel Edison C++ 4 PWM Example Code

/*     ---------------------------------------------------------

*     |  Intel Edison C++ Example Code                         |

*     |   PWM EXAMPLE                                                                |

*     ---------------------------------------------------------

* This example tries to control 4 PWM signals with Intel Edison

* Makefile: g++ -lmraa –o PWM_EDISON PWM_EDISON.cpp

* ./PWM_EDISON 0.5

*/

#include <iostream>

#include <stdio.h>

#include <signal.h>

#include <unistd.h>

#include <mraa.h>

#include <mraa/pwm.h>

using namespace std;

sig_atomic_t volatile isrunning = 1;

void sig_handler(int signum);

int main(int argc, char *argv[])

{

       signal(SIGINT, &sig_handler);

       float       duty=1;     /* Will hold the duty cycle */

       mraa_init();

       mraa_pwm_context PWM_3_pin;

       mraa_pwm_context PWM_5_pin;

       mraa_pwm_context PWM_6_pin;

       mraa_pwm_context PWM_9_pin;

       PWM_3_pin = mraa_pwm_init(3);

       if (PWM_3_pin == NULL) {

             cout << "Error in PWM_3_pin...\n";

       }

       PWM_5_pin = mraa_pwm_init(5);

       if (PWM_5_pin == NULL) {

             cout << "Error in PWM_5_pin...\n";

       }

      

       PWM_6_pin = mraa_pwm_init(6);

       if (PWM_6_pin == NULL) {

             cout << "Error in PWM_6_pin...\n";

       }

       PWM_9_pin = mraa_pwm_init(9);

       if (PWM_9_pin == NULL)

       {

                    cout << "Error in PWM_9_pin...\n";

       }

       mraa_pwm_period_ms(PWM_3_pin, 1);//period 1ms

       mraa_pwm_period_ms(PWM_5_pin, 1);

       mraa_pwm_period_ms(PWM_6_pin, 1);

       mraa_pwm_period_ms(PWM_9_pin, 1);

      

       duty = atof(argv[1]);//tries to convert the input to a floating number

       duty = duty <= 1 ? duty : 1;//if the number  is higher than 1 then duty=1;

       cout << "The duty selected is: " <<duty << endl;

       mraa_pwm_write(PWM_3_pin, duty);

       mraa_pwm_write(PWM_5_pin, duty);

       mraa_pwm_write(PWM_6_pin, duty);

       mraa_pwm_write(PWM_9_pin, duty);

       cout << "Press any key and then Enter to exit from the aplication..."<<endl;

       mraa_pwm_enable(PWM_3_pin, 1);

       mraa_pwm_enable(PWM_5_pin, 1);

       mraa_pwm_enable(PWM_6_pin, 1);

       mraa_pwm_enable(PWM_9_pin, 1);

       while (isrunning)

       {     

             if (cin.get()) break;

       }

       cout << "Closing application..." << endl;

       mraa_pwm_enable(PWM_3_pin, 0);

       mraa_pwm_enable(PWM_5_pin, 0);

       mraa_pwm_enable(PWM_6_pin, 0);

       mraa_pwm_enable(PWM_9_pin, 0);

       return MRAA_SUCCESS;

}

void sig_handler(int signum)

{     

       if (signum == SIGINT) isrunning = 0;

}