why the timer callback can't be called in a loop?

[zk017]

SDK14+NRF52832.

I used one timer to do something every millisecond. and I used another function to do a loop action, the function maybe breaked if the time period exceed one value.

now I found when execute the loop action function, the timer can't trigger, if normally it should be called every millisecond.

#define NRF_TICK_INTERVAL      APP_TIMER_TICKS(1)
static void nrf_tick_init(void)
{
	uint32_t err_code;
    
	err_code = app_timer_create(&m_nrf_tick_timer_id,  APP_TIMER_MODE_REPEATED,  nrf_tick_event_handler);
	APP_ERROR_CHECK(err_code);
	err_code = app_timer_start(m_nrf_tick_timer_id, NRF_TICK_INTERVAL, NULL);
	APP_ERROR_CHECK(err_code);
}

void nrf_ticks_set(unsigned long tick)
{
	nrf_ms_ticks = tick;
}

//-----------------------------------------------------------------
int nrf_ticks_get(unsigned long *tick)  
{
    *tick = nrf_ms_ticks;
    return 0;
}


//-----------------------------------------------------------------
static void nrf_tick_event_handler(void * p_context)
{

	UNUSED_PARAMETER(p_context);
	nrf_ms_ticks++;
	NRF_LOG_PRINTF("%s\n", __FUNCTION__);
}
void home_motor_then_stop(void)
{
	NRF_LOG_PRINTF("HOMEing...\n");
	bool tail_flag = Is_arrived_tail_point();
	unsigned long start_time = 0, end_time = 0, interval_len;
	
	if(false == tail_flag)
	{
		set_motor_to_tail(GLOBAL_MIN_GRADE); 
		nrf_ticks_get(&start_time);
		end_time = start_time;
		while((false==tail_flag)&&((end_time-start_time)<=30000)) //the end_time can't increase
		{
			nrf_ticks_get(&end_time); //always get the same value
			interval_len = end_time - start_time;
			NRF_LOG_PRINTF("stop_cup_then_home, interval_len=%d\n ", interval_len);
			tail_flag = Is_arrived_tail_point();
			
		};
		stop_motor();
	}
}

int main(void)
{

	application_init();//here called nrf_tick_init()
	
	home_motor_then_stop(); //
	
	while(1)
	{
		power_manage();
	}
} //

I found when run into the while of home_motor_then_stop(), the nrf_tick_event_handler can't trigger. this lead the function can't return.

what fault ?

[Jared]

Hi,

It's difficult to tell what the issue is without reproducing the issue myself. What priorities does the timer interrupts have? The application will not handle an interrupt immediately if it's already handling another interrupt with the same priority. The interrupt will be handled after it has returned from the first. 

regards

Jared 

[mark_l]

How are you determining it isn't running? via the log prints? your while loop is heavily spamming the log, potentially blocking anything else from running or printing, depending on the output channel for the log data. Try taking the log print out of the while loop to see what happens. Also how is nrf_ms_ticks defined? Has it been declared as volatile?

[zk017]

Yes， I found the log in while, NRF_LOG_PRINTF("stop_cup_then_home, interval_len=%d\n ", interval_len); always printed the same value, this can verify the nrf_tick_event_handler havn't executed. and some time passed, system restarted, which meet the watch dog 's function，havn't feed the watch dog resulted system restart.

[mark_l]

How is nrf_ms_ticks declared?

[zk017]

static volatile uint32_t nrf_ms_ticks = 0;  and only be used in the following functions:

static volatile uint32_t nrf_ms_ticks = 0;
int nrf_ticks_get(unsigned long *tick)  
{
    *tick = nrf_ms_ticks;
	//NRF_LOG_PRINTF("%s %d\n", __FUNCTION__, nrf_ms_ticks);
	return 0;
}


//-----------------------------------------------------------------
static void nrf_tick_event_handler(void * p_context)
{
	UNUSED_PARAMETER(p_context);
	nrf_ms_ticks++;
	//NRF_LOG_PRINTF("%s\n", __FUNCTION__);
}