IOT Timer Resolution ICMP example

[gsalazar]

Hi, 

I'm using the ICMP example provided in SDK 15 to test the 6lowpan and wanted to check the RTT from the nrf52832 dev kit.

I managed to do so with the IOT Timer, I check the time when sending the ICMP packet and print the difference upon receiving it, I am using the iot_timer_wall_clock_get function on both cases and I configure the resolution in the sdk_config.h in the IOT_TIMER_RESOLUTION_IN_MS define.

However I cannot set a resolution under 5ms, otherwise the system crashes and the code does not run. I get 

<error> app: Fatal error
<warning> app: System reset

Do you know how I can solve this issue? I would like to have 1 ms resolution for my tests.

Thank you 

[Edvin]

Hello,

Where does this error come from?

When you get these kind of errors, they typically come from one of the APP_ERROR_CHECK(err_code); where the err_code != NRF_SUCCESS (0).

 

Try to define DEBUG in your preprocessor defines, and then disable optimization (set it to -O0). Then try to debug, and set a breakpoint on line 90 in app_error.c, and see if it stops there. Then you can add *p_info to watch, and check where the APP_ERROR_CHECK(err_code); that triggered is located. See if you can make any sense of the call that returned the err_code, and why it did.

 

Best regards,

Edvin

[gsalazar]

Hi, 

I did what you sugested and the error comes from the main.c of the ICMP example in line 526, which corresponds to the iot_timer_init function. The error code is 7, which is INVALID_PARAMETER.

After checking, I observed that in the app_timer.h the APP_TIMER_MIN_TIMEOUT_TICKS was defined as 5 ms. Changed that to 1 ms and now everything works.

Thank you for pointing me in the right direction.

Best regards