Using timer with sd_app_evt_wait()

[Jarmo]

I am trying to run my program once per second using timer. The timer is initialized as follows:

APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_MAX_TIMERS, APP_TIMER_OP_QUEUE_SIZE, false);

err_code = app_timer_create(&m_timer_id, APP_TIMER_MODE_REPEATED, timeout_handler);

err_code = app_timer_start(m_timer_id, TIMER_INTERVAL, NULL);

The main loop is then simply:

while (1) { sd_app_evt_wait(); do_my_things(); }

However, now that timer triggers first time, the loop starts to run at full speed. Should I somehow acknowledge the timer event in order to be able to wait again?

[RK]

You're not supposed to do_your_things() in the main loop - you're supposed to do them in the timeout_handler. What's in your timeout handler? sd_app_evt_wait() can return at any time, many times, all the time whenever any event in the system is triggered, that's got no relationship to the app timer at all.

[Susheel Nuguru]

please give more information on what SDK, SD and hardware you are using. There is nothing wrong with the chunk of code you put here. But it is difficult to say anything without the context of where this is being used.

[Jarmo]

Yeah, that was a bit stripped code. I have a boolean flag 'timeout' in the timeout_handler and now I am checking that flag in the main loop. It seems that it is almost working, but instead of one second interval, the flag seems to be set once per two seconds. But when I connect via BT-LE, it starts to run correctly once per second. Strange behaviour, any ideas what could cause that?

[Jarmo]

Found the reason. Due to my contaminated software structure, there were two calls of sd_app_evt_wait(). When BT-LE is connected, there are enough events to capture all the timeouts, but if not, half of the timer triggers are just missed. This case is probably quite solved now. Thanks!