Switching pins between modes.

Hello Mark,

Thanks for reaching out!

The following is a simple script I wrote that successfully uses PWM and then GPIO functions on the same pin. I tested this successfully on a LED:

#include <unistd.h>

#include "mraa.h"

int
main()
{
    mraa_init();
    //! [Interesting]
    mraa_pwm_context pwm;
    pwm = mraa_pwm_init(26);
    if (pwm == NULL) 
    {
        return 1;
    }
    mraa_pwm_period_us(pwm, 200);
    mraa_pwm_enable(pwm, 1);

    float value = 0.0f;
    int count = 0;

    while (count < 250) 
    {
        count = count + 1;
        value = value + 0.01f;
        mraa_pwm_write(pwm, value);
        usleep(50000);
        if (value >= 1.0f) 
        {
            value = 0.0f;
        }
        float output = mraa_pwm_read(pwm);
        printf("PWM value is %f\n", output);
    }

    mraa_gpio_context gpio;
    int ledstate = 0;
    gpio = mraa_gpio_init(26);
    mraa_gpio_dir(gpio, MRAA_GPIO_OUT);
    count = 0;

    while(count < 5)
    {
        count = count + 1;
        ledstate = !ledstate;
        mraa_gpio_write(gpio, ledstate);
        sleep(1);
    }
    return 0;
}

I hope this simple code helps you,
Pedro M.

I just tested this again on my Joule and I'm having the same behavior as you. PWM works only the first time, I'm not sure what might be happening. You see, I wrote that script a while ago, originally for a test on my Edison and I worked with no issues, PWM continued to work without any problems. So, I took that code, I slightly modified it to work on Joule and I only tested it once on Joule to make sure it worked before sharing it with you. So, I completely missed this issue. 

Please let us investigate about this behavior and we'll get back to you once we have any useful update.

Pedro M.

Hello Mark,
 
We completely understand your situation. I would like to point out that we are currently working on this. It is really helpful that you highlighted this behavior so we can work on preventing it. Right now, we have no updates but as soon as we know anything new, we'll make sure to share it with you.
 
Pedro M.

Hello Mark,

Thank you for your interest in Joule. 

We would like to offer our sincere apologies for delaying a response to your issue. We have confirmed the issue you brought to our attention and are working diligently to resolve it. Unfortunately, we do not have an ETA for release.

Pedro M.