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pwm.c
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pwm.c
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/*
pwm.c
This example creates a PWM loop on a period of 500us that will vary between 0% and 100% and vice versa.
This example can be used to show how to use PWM in order to modify the brightness in a LED.
This example wa written with the latest version of mraa (1.7.0) when originally posted.
This example code is in the public domain.
Revision History
------------------------------------------------
Author Date Description
------------------------------------------------
Pedro Mora 6-14-2017 Example created
*/
#include <unistd.h>
#include <stdbool.h>
#include "mraa.h"
int main()
{
mraa_init();
mraa_pwm_context pwm;
pwm = mraa_pwm_init(3);
if (pwm == NULL)
return 1;
mraa_pwm_period_us(pwm, 500);
mraa_pwm_enable(pwm, 1);
float value = 0.0f;
bool ch = true;
while(true)
{
if(value >= 1.0f)
ch = false;
if(value <= 0.0f)
ch = true;
if(ch == true)
value = value + 0.05f;
if(ch == false)
value = value - 0.05f;
mraa_pwm_write(pwm, value);
usleep(50000);
float output = mraa_pwm_read(pwm);
printf("PWM value is %f\n", output);
}
return 0;
}