app_timer_cnt_get not giving correct values

[Surya]

Hi,

I am using app_timer and SoftDevice in NRF52810.

I am storing app_timer_cnt_get() value after releasing button and after completing BLE Advertisment.

as I am starting BLE advertising after button release, BLE Advertising completed value must be greater than Button released time

but sometimes I am getting lesser values.

Note:

Total Observation will be completed in less than 10 seconds so not RTC overflow problem.

[ovrebekk]

Hi

What kind of values do you see when this issue occurs?

Best regards
Torbjørn

[Surya]

Hi,

I have already mentioned Later values coming lesser than previous values.

button release  3493 and BLEadv stops 593

button release   4067 and BLE adv stops 670

and please note that I have mentioned only values that are not as expected.

normally BLE adv stops  ~5000 to 6000

Note: all numbers mentioned are RTC counter values and RTC frequency is 16384 Hz

[Henry_Chou]

Is there any possible that the other routines clear the RTC counts? If you never change the overflow mask,, the default overflow value is 0xFFFFFFUL. You never get the overflow value within 10 seconds. So that I doubt that change the overflow mask or clear RTC counter or system reset. 

[Surya]

1. System Reset is not happening as BLE adv starts only when the button released.

2. I didn't change anything in the app_timer library.

3. I am not doing clear or resetting RTC in my code.

if I stop all timers RTC counter will be reset?

[Henry_Chou]

Maybe it will be a trace entry point for you. You may check the SD application documents. SD will use the RTC0 and the other system resource. In your application, I  think it might be caused by SD. If it's possible, you may apply another RTC for counting.  

No....app_timer2.c using RTC1.......Sorry,....I have no idea for your case.

[Surya]

yes app_timer library using RTC1 and SD using RTC0. but I don't understand RTC1 reset happening.

[ovrebekk]

Hi 

Is there a lot of difference between your code and the standard examples? 

There is no reason the RTC1 should reset before it overflows, unless there is some other issue with the code. 

Best regards
Torbjørn