RE: Unable to Toggle PWM Module Off and On

Pawel Zadrozniak — Thu, 12 Nov 2015 13:40:07 GMT

The power enable/disable and power consumtion related issues has been fixed in SDK v10.0 available here: developer.nordicsemi.com/.../ .

RE: Unable to Toggle PWM Module Off and On

Cory Mast — Fri, 25 Sep 2015 18:53:08 GMT

I believe there may be an error in the app_pwm.c file, specifically regarding the app_pwm_enable function. When I look at the app_pwm disable function:

void app_pwm_disable(app_pwm_t const * const p_instance)
{
  app_pwm_cb_t * p_cb = p_instance->p_cb;
  ASSERT(p_cb->state != NRF_DRV_STATE_UNINITIALIZED);
  nrf_drv_timer_disable(p_instance->p_timer);
  pwm_irq_disable(p_instance);
  p_cb->state = NRF_DRV_STATE_INITIALIZED;
  return;
}

There is a function that disables the IRQ for that instance:

nrf_drv_timer_disable(p_instance->p_timer);

But if we look at the function declaration for app_pwm_enable:

void app_pwm_enable(app_pwm_t const * const p_instance)
{
  app_pwm_cb_t * p_cb = p_instance->p_cb;
  ASSERT(p_cb->state != NRF_DRV_STATE_UNINITIALIZED);
  nrf_drv_timer_enable(p_instance->p_timer);
  p_cb->state = NRF_DRV_STATE_POWERED_ON;
  return;
}

There is no function to enable the IRQ for the specified instance. By adding the following line:

pwm_irq_enable(p_instance);

to the app_pwm_enable function we end up with:

void app_pwm_enable(app_pwm_t const * const p_instance)
{
  app_pwm_cb_t * p_cb = p_instance->p_cb;
  ASSERT(p_cb->state != NRF_DRV_STATE_UNINITIALIZED);
  nrf_drv_timer_enable(p_instance->p_timer);
  pwm_irq_enable(p_instance);
  p_cb->state = NRF_DRV_STATE_POWERED_ON;
  return;
}

This seems to have fixed the problems with PWM that I was having. Was this just a bug in the SDK or was I doing something wrong? I can now toggle PWM on and off and everything else appears to be functioning properly. Any clarification or confirmation would be great and I hope this helps anyone else who may be struggling with the same issue.

Thanks!