App timer misfire after 4000 mSec interval

RE: App timer misfire after 4000 mSec interval

Pooja Uchagaonkar — Fri, 04 Sep 2020 11:42:54 GMT

Ohh.... it's my mistake.

Thank you so much Jordan.

RE: App timer misfire after 4000 mSec interval

Jørgen Holmefjord — Fri, 04 Sep 2020 11:00:13 GMT

The APP_TIMER_TICKS macro is defined like this:

((uint32_t)ROUNDED_DIV(                        \
            (MS) * (uint64_t)APP_TIMER_CLOCK_FREQ,         \
            1000 * (APP_TIMER_CONFIG_RTC_FREQUENCY + 1)))

As you can see, it returns a 32-bit unsigned integer, and uses a 64-bit unsigned integer internally to make sure the accuracy is not lost due to variable overflow.

This is why I asked what data type NORMAL_MODE_MEAS_INTERVAL is in your application. If this is declared as uint16_t and this is the variable you check for the output from APP_TIMER_TICKS, you will get the behavior that you describe.

RE: App timer misfire after 4000 mSec interval

Pooja Uchagaonkar — Fri, 04 Sep 2020 10:54:13 GMT

Hi Jorgan,

Sorry for late reply. I was on leave due to unwell health conditions so couldn't able to work on this.

Yes, right. The value of APP_TIMER_CONFIG_RTC_FREQUENCY is set to1 in sdk_config file, which corresponds to a frequency of 16384 Hz)

The value returned by APP_TIMER_TICKS is 0 for 4000 mSec.

The value returned by APP_TIMER_TICKS 16384 for 1000 mSec and 63989 value for 3900 mSec. But for 4050 mSec, it returns APP_TIMER_TICKS value is 819.

If I set APP_TIMER_CONFIG_RTC_FREQUENCY is 0, which corresponds to a frequency of 32767 Hz, The value returned by APP_TIMER_TICKS value 0 for 2000mSec and 4000 mSec.

If I set APP_TIMER_CONFIG_RTC_FREQUENCY is 3, which corresponds to a frequency of 8192 Hz, The value returned by APP_TIMER_TICKS is 49152 for 6000 mSec and APP_TIMER_TICKS value 0 for 8000 mSec .

My observation is APP_TIMER_TICKS value is overload from 65535 to 0. I have done exercise for different time set and frequency by setting APP_TIMER_CONFIG_RTC_FREQUENCY 0 to 4 which is corresponds to 32768 Hz, 16384 Hz, 10922 Hz and 8192 Hz frequency respectively. I added reading file herewith. Can you please check at once and revert me on this?

devzone.nordicsemi.com/.../AppTimerTicks-reading-for-different-rtc-timer-frequnecy.xlsx

If I set APP_TIMER_CONFIG_RTC_FREQUENCY is 3, which corresponds to frequency of 8192 Hz, I got resolution from 6 Sec to 0.15 mSec which I need to set in my application. But I just have one question that, the ble stack and soft device use same app_timer_2 for ble_stack and soft device. If I set 8192 Hz frequency, is this suitable for this?

RE: App timer misfire after 4000 mSec interval

Jørgen Holmefjord — Wed, 26 Aug 2020 15:09:33 GMT

[quote user="Pooja Uchagaonkar"]The value returned by APP_TIMER_TICKS is nearly about 1000 ms above 4000 mSec.[/quote]

Not sure what you mean by this. If you input 4000 ms and the frequency is 16384 Hz, this should return 65536. Which data type is NORMAL_MODE_MEAS_INTERVAL?

[quote user="Pooja Uchagaonkar"]APP_TIMER_CONFIG_RTC_FREQUENCY set as 16384 Hz.[/quote]

Is the value of the config set to 16384, or is it set to 1 (which corresponds to a frequency of 16384 Hz)?

RE: App timer misfire after 4000 mSec interval

Pooja Uchagaonkar — Wed, 26 Aug 2020 04:48:05 GMT

Hi Jorgen,

The project is almost in last phase and I completely stuck due to this issue. Thank you so much for your reply.

The value returned by APP_TIMER_TICKS is nearly about 1000 ms above 4000 mSec.

APP_TIMER_CONFIG_RTC_FREQUENCY set as 16384 Hz.

Actually I used this app timer for variable time interval as shown below code. Here the RPM range varies from 0.25 to 100 and so accordingly time interval changing from 6 Sec to 15 mSec.

It works perfectly for 100 to 0.38 RPM setting but misfires below this.

void start_normal_mode()
{
   ret_code_t err_code;
   float RPM;
   RPM = Read_RPM_Param_from_flash();
   SamplingRate = 60/(40 * RPM);
   SamplingRate_ms = SamplingRate * 1000;

   NORMAL_MODE_MEAS_INTERVAL = APP_TIMER_TICKS(SamplingRate_ms);

   if(normal_mode_reading_count == 0)
   {
      err_code = app_timer_start(m_normalmode_timer_id, NORMAL_MODE_MEAS_INTERVAL, NULL);
      APP_ERROR_CHECK(err_code);
   }
}

//code in main while loop
while(1)
{
    if(RTCMinInterrpt_Flag == 1)    
     {          
        External_RTC_GetDateTime(&GetRTC_DateTime);
        printf("\r\n Date- %d/%d/%d, Time- %d:%d:%d", GetRTC_DateTime.date, GetRTC_DateTime.month, GetRTC_DateTime.year, GetRTC_DateTime.hour, GetRTC_DateTime.minute, GetRTC_DateTime.second);
        RTCMinInterrpt_Flag = 0;
        Normal_Mode_Reading_Flag = 1;
        normal_mode_hour_index++;
        start_normal_mode();       //calculate sampling rate and start timer
     }
     
     if(Normal_Mode_Timer_Flag == 1)
         {          
             if(normal_mode_reading_count < normal_mode_total_reading)
             {
                  read_datetimestamp_and_sensor_Data();
                  memcpy(&Normal_Mode_Handling_Buff[normal_mode_reading_count*NormalMode_OneReadingcount], DateTimeStamp_and_Sensor_Buff, sizeof(DateTimeStamp_and_Sensor_Buff));
                  normal_mode_reading_count ++;
                  Normal_Mode_Timer_Flag = 0;
              }
              else
              {
                    normal_mode_reading_count = 0;
                    app_timer_stop(m_normalmode_timer_id);     //stop timer                               
              }
          }      
}

Please let me know if anything I can do

Regards,

Pooja Uchagaonkar

RE: App timer misfire after 4000 mSec interval

Jørgen Holmefjord — Mon, 24 Aug 2020 14:40:39 GMT

What is the value returned by APP_TIMER_TICKS when you input a value above 4000 ms? What is the config APP_TIMER_CONFIG_RTC_FREQUENCY set to?

Can you provide a minimal example that can be used to reproduce this issue?

RE: App timer misfire after 4000 mSec interval

Pooja Uchagaonkar — Mon, 24 Aug 2020 12:04:18 GMT

HI Jorgen,

I used app_timer2. But issue is not resolved. I also checked with this nrf_drv_timer but same issue happened. Can you please help me out?

RE: App timer misfire after 4000 mSec interval

Pooja Uchagaonkar — Wed, 15 Jul 2020 10:47:03 GMT

Sorry Sir for late reply,

I was trying to resolve this with by implementing nrf_drv_timer, but same thing happened.

But I didn't check it with app_timer2. I will do this and let you know soon.

Thanks,

Pooja Uchagaonkar

RE: App timer misfire after 4000 mSec interval

Jørgen Holmefjord — Thu, 09 Jul 2020 13:37:28 GMT

Hi,

The behavior you describe sounds similar to this known issue. The solution is to switch to using app_timer2, which was introduced in SDK 15.0.0 as an experimental library. In SDK 16.0.0, app_timer2 was updated to production quality and used by default for all examples.

Instructions on how to switch app_timer are given in this post.

Best regards,
Jørgen