RE: How to process a queue in the background?

Håkon Alseth — Thu, 22 Feb 2018 14:42:56 GMT

Hi,

This is commonly done using some sort of scheduler, to reduce the processing time in interrupts and change priority level from interrupt context to thread (also called main) context.

We have the library app_scheduler than can do this, where you add the call to app_sched_execute() to the main loop.

To add an item to the queue, you can call app_sched_event_put(NULL, 0, my_function); and it will get processed when you enter the main for-loop.

Many BLE-examples (ble_app_hids_*) has the scheduler initialized and uses this for BLE events and app_timer handlers, and the nfc\writeable_ndef_msg uses it as well.

Most RTOSes have the same concept available.

You can also go the other way around. Everytime fooA or fooB is called, you set a interrupt pending, and have a software interrupt in your module, here shown with some crude code:

ret_t fooA(...)
{
  ...
  ret = add_to_queue(fooA);
  if ( ret != success)
    NVIC_SetPending(SWIx_IRQn);
  return ret;
}

ret_t fooB(...)
{
  ...
  ret = add_to_queue(fooB);
  if ( ret != success)
    NVIC_SetPending(SWIx_IRQn);
  return ret;
}

void SWIx_IRQHandler(void)
{
  process_queue();
}

static ret_t fooA_process(...)
{
  ...
}

static ret_t fooB_process(...)
{
  ...
}

It all depends on how this module is hooked into the rest of your system.

Cheers,

Håkon