Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

RE: Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

Susheel Nuguru — Tue, 30 Mar 2021 09:04:57 GMT

Ahha, Thanks for those feedback. That is very kind of you to come back to the forum and report your finding. Very much appreciated.

RE: Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

Mathew Key — Mon, 29 Mar 2021 14:02:24 GMT

Thats because there isnt anything that needs to be resolved. Its more an FYI for everyone else

RE: Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

Susheel Nuguru — Mon, 29 Mar 2021 13:46:48 GMT

Mathew,
I got assigned to this case now, and did not manage to take a look at it today. Normally I have confidence that most of the FreeRTOS cases can be solved, I will comeback to you tomorrow with my observations.

Thanks for your patience.

RE: Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

Mathew Key — Fri, 26 Mar 2021 18:03:32 GMT

Add the below to FreeRTOSConfig.h to fix the FPU issue. This is from https://devzone.nordicsemi.com/f/nordic-q-a/39918/going-low-power-in-freertos-app/294672#294672

/* Fix for Errata #87 nrf52832 */                                       \
#define configPRE_SLEEP_PROCESSING(xMIdleTime) if ( xMIdleTime > 0 ) { \
        __set_FPSCR(__get_FPSCR() & ~(0x0000009F));                     \
        (void) __get_FPSCR();                                           \
         NVIC_ClearPendingIRQ(FPU_IRQn);                                \
}

RE: Getting (and GOT) low power working in FreeRTOS on nRF52832 and SDK 17.0.2

Anthony Ambuehl — Fri, 26 Mar 2021 17:30:44 GMT

I've also found a few other issues to consider:

* unhandled FPU exceptions will immediately exit from sleep, make sure you are clearing them.

* NRF_LOG library in SDK 16 was setup to busy loop and never block. (this may be fixed in newer SDK)