app_timer APP_TIMER_MODE_REPEATED not working after serveral hours

[John12]

Hi, I'm build an applicaiton using app_timer
Mode: APP_TIMER_MODE_REPEATED
Interval: 5 minutes
Flow:
- after 5 minutes I will restart the timer (stop and create a new one)
- in app_timer_handler I set a flag and logging that has expired to indicate the timer has expired and now it need to restart the timer
- I hang debugging almost 6 hours. Everything worked well, but after 5 hours since I start debug. The app_timer not working (app_timer_handler no longer set the flag and logging the timer has expried like normal)
I'm sure device is working because when I connect BLE device still advertising and connectable and debug terminal display connected normally. 

Note: I'm using 2 libuartes in soft-device BLE application (1 libuarte using app_timer)
SDK:16
nRF52833 custom board
app_timer using internal LFCLK
Here is my sdk_config.h

1016.sdk_config.h
Thank you for your support !
Best Regard

[Jørgen Holmefjord]

Hi,

Are you using app_timer2, or the old app_timer implementation? There are known issues with the old implementation that match your symptoms.

Please try changing to app_timer2 and see if this resolves your issues.

Best regards,
Jørgen

[Hermes LP]

Hello Team,

I am facing the same issue with app_timer2 and SDK17.
My implementation is similar to John12's; I have app_timers running to control the modem state. In the timer handler, a flag is set, on which a function in main reads, executes the modem code, and then clears it.
Sometimes I need the modem code to execute faster, so I periodically stop and start the timers.

The code runs for some time; however, after hours, all app_timers stop firing without any error. I have APP_ERROR_CHECK() on both start and stop functions.

app_timer_cnt_get()  still increments but however all app_timers stops firing.
Any guide to resolve this is highly appreciated. 

Thanks.



sdk config

// <e> APP_TIMER_ENABLED - app_timer - Application timer functionality
//==========================================================
#ifndef APP_TIMER_ENABLED
#define APP_TIMER_ENABLED 1
#endif
// <o> APP_TIMER_CONFIG_RTC_FREQUENCY  - Configure RTC prescaler.
 
// <0=> 32768 Hz 
// <1=> 16384 Hz 
// <3=> 8192 Hz 
// <7=> 4096 Hz 
// <15=> 2048 Hz 
// <31=> 1024 Hz 

#ifndef APP_TIMER_CONFIG_RTC_FREQUENCY
#define APP_TIMER_CONFIG_RTC_FREQUENCY 1
#endif

// <o> APP_TIMER_CONFIG_IRQ_PRIORITY  - Interrupt priority
 

// <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// <0=> 0 (highest) 
// <1=> 1 
// <2=> 2 
// <3=> 3 
// <4=> 4 
// <5=> 5 
// <6=> 6 
// <7=> 7 

#ifndef APP_TIMER_CONFIG_IRQ_PRIORITY
#define APP_TIMER_CONFIG_IRQ_PRIORITY 6
#endif

// <o> APP_TIMER_CONFIG_OP_QUEUE_SIZE - Capacity of timer requests queue. 
// <i> Size of the queue depends on how many timers are used
// <i> in the system, how often timers are started and overall
// <i> system latency. If queue size is too small app_timer calls
// <i> will fail.

#ifndef APP_TIMER_CONFIG_OP_QUEUE_SIZE
#define APP_TIMER_CONFIG_OP_QUEUE_SIZE 100
#endif

// <q> APP_TIMER_CONFIG_USE_SCHEDULER  - Enable scheduling app_timer events to app_scheduler
 

#ifndef APP_TIMER_CONFIG_USE_SCHEDULER
#define APP_TIMER_CONFIG_USE_SCHEDULER 0
#endif

// <q> APP_TIMER_KEEPS_RTC_ACTIVE  - Enable RTC always on
 

// <i> If option is enabled RTC is kept running even if there is no active timers.
// <i> This option can be used when app_timer is used for timestamping.

#ifndef APP_TIMER_KEEPS_RTC_ACTIVE
#define APP_TIMER_KEEPS_RTC_ACTIVE 0
#endif

// <o> APP_TIMER_SAFE_WINDOW_MS - Maximum possible latency (in milliseconds) of handling app_timer event. 
// <i> Maximum possible timeout that can be set is reduced by safe window.
// <i> Example: RTC frequency 16384 Hz, maximum possible timeout 1024 seconds - APP_TIMER_SAFE_WINDOW_MS.
// <i> Since RTC is not stopped when processor is halted in debugging session, this value
// <i> must cover it if debugging is needed. It is possible to halt processor for APP_TIMER_SAFE_WINDOW_MS
// <i> without corrupting app_timer behavior.

#ifndef APP_TIMER_SAFE_WINDOW_MS
#define APP_TIMER_SAFE_WINDOW_MS 300000
#endif

// <h> App Timer Legacy configuration - Legacy configuration.

//==========================================================
// <q> APP_TIMER_WITH_PROFILER  - Enable app_timer profiling
 

#ifndef APP_TIMER_WITH_PROFILER
#define APP_TIMER_WITH_PROFILER 1
#endif

// <q> APP_TIMER_CONFIG_SWI_NUMBER  - Configure SWI instance used.
 

#ifndef APP_TIMER_CONFIG_SWI_NUMBER
#define APP_TIMER_CONFIG_SWI_NUMBER 0
#endif

app_timer stop/start functon

void timer_start_v2(uint8_t timerid, uint32_t time){
	static bool timers_created = false;
	uint32_t err_code;
	
	if(timers_created==false){
		err_code = app_timer_create(&m_timer0, APP_TIMER_MODE_REPEATED, timer0_timeout_handler);
		APP_ERROR_CHECK(err_code);
		
		err_code = app_timer_create(&m_timer1, APP_TIMER_MODE_REPEATED, timer1_timeout_handler);
		APP_ERROR_CHECK(err_code);
		timers_created=true;
		
		//err_code = app_timer_create(&m_timer2, APP_TIMER_MODE_REPEATED, timer2_timeout_handler);
		//APP_ERROR_CHECK(err_code);
		//timers_created=true;
	}
	//convert time in ms to ticks => 16,384 ticks = 1000ms
	time = (16384*time)/1000;

	
	switch(timerid){
		case 0:{
			if(timer0_started==true){
				err_code = app_timer_stop(m_timer0); //stop current timer
				APP_ERROR_CHECK(err_code);
				timer0_started=false;
			}
			err_code = app_timer_start(m_timer0, APP_TIMER_TICKS(time), NULL);
			APP_ERROR_CHECK(err_code);
			timer0_time = time;
			timer0_started = true;
		}break;
		case 1:{
			if(timer1_started==true){
				err_code = app_timer_stop(m_timer1); //stop current timer
				APP_ERROR_CHECK(err_code);
				timer1_started=false;
			}
			err_code = app_timer_start(m_timer1, APP_TIMER_TICKS(time), NULL);
			APP_ERROR_CHECK(err_code);
			timer1_time = time;
			timer1_started = true;
		}break;
		//case 2:{
		//	if(timer2_started==true){
		//		err_code = app_timer_stop(m_timer2); //stop current timer
		//		APP_ERROR_CHECK(err_code);
		//		timer2_started=false;
		//	}
		//	err_code = app_timer_start(m_timer2, time, NULL);
		//	APP_ERROR_CHECK(err_code);
		//	//timer2_time = time;
		//	timer2_started = true;
		//}break;
		
		default:break;
	}
		
}

Handlers

void timer0_timeout_handler(void * p_context)
{
	UNUSED_PARAMETER(p_context);
	//timerhandler0();
	timer_run_flag |= 0x01;
}

void timer1_timeout_handler(void * p_context)
{
	UNUSED_PARAMETER(p_context);
	//timerhandler1();
	timer_run_flag |= 0x02;
}

Inside Main loop

```if(timer_run_flag & 0x01){ //timer0 flag
		timerhandler0();
		timer_run_flag &= (uint8_t)~0x01; // Clear the flag
	}
	if(timer_run_flag & 0x02){ //timer1 flag
		timerhandler1();
		timer_run_flag &= (uint8_t)~0x02; // Clear the flag
	}
	

[Hermes LP]

Adding more context

1. Here is where app_timer stops firing


2. Can still connect with BLE
(There is a new app_timer created here for monitoring connection time)



3. Hardfault on ble disconnect
(Disconnect stops the app_timer above)


4. map file


Does the hard fault indicate a problem with the nrf_sortlist_remove function? 

[Jørgen Holmefjord]

If you can still connect, but app_timer events are not handled, it sounds like your code might be stuck in a higher priority interrupt context. Have you debugged the application to see if it is stuck somewhere?