Prevent sd_app_evt_wait from wakeup

[bloobird0]

hello,

I'm currently stuck with sd_app_evt_wait() function leaving for an unknown reason. This function is called in the main loop.

The only reasons that shall exit the low power mode are:

- RTC1 (app_timer) callback trigger, it is triggered every 100ms

- one of 10 GPIOs state change (buttons)

Could you please help me find the reason why the execution does not stay in sd_app_evt_wait wakeup() and eventually guide me to a solution?  If you need more details, please aks, I don't know what you would need.

Note:

- This function leaves with error code 0 and NVIC_GetPendingIRQ() also returns 0 just after this function

- my board does not have any external XTAL, instead I use LF_RC clock and I manually start LFCLK before initializing the softdevice. I do not manually start HFCLK, does the softdevice initialization does it automatically?

- if I do not initialize the softdevice and call  __WFI();__WFE();__SEV();__WFE(); I stay in low power mode. The simple fact to call SOFTDEVICE_HANDLER_INIT() introduces my problem.

- I don't know how to debug to find out the reason

- because of this problem, the board power consumption is 7,5mA instead of few µA which is a current NO GO for production.

- Does it have to do with a disabled interrupt? How could I know which disabled interrupt occurs?

Thanks in advance for your help.

[Vidar Berg]

Hello,

Does the program get past ble_stack_init() and are you calling sd_app_evt_wait() from the main loop? Remember that you must specify what LF source to use when you call sd_softdevice_enable(). 

Best regards,

Vidar

 

[bloobird0]

yes, the program passes the ble_stack_init() and yes sd_app_evt_wait() is called in the main loop.

I can advertise, connect, read/write characteristics.... it's just that the µC does not stay in low power mode and leaves sd_app_evt_wait(), I don't know how to find the wakeup reason.

 

The clock assignment is the following:

 

#define NRF_CLOCK_LFCLKSRC {.source = NRF_CLOCK_LF_SRC_RC , \
.rc_ctiv = 16, \
.rc_temp_ctiv = 2, \
.xtal_accuracy = 0} ///ignored when using LF RC

nrf_clock_lf_cfg_t clock_lf_cfg = NRF_CLOCK_LFCLKSRC;

// Initialize SoftDevice.
SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

 

 

 

[Vidar Berg]

Thanks for confirming, so it sounds like there is a pending interrupt that prevents the CPU from entering sleep, but not sure why it only happens when the softdevice is enabled . Do you have any floating point instructions in your code? In that case you should implement the workaround for errata 87: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.Rev2.errata/dita/errata/nRF52832/Rev2/latest/anomaly_832_87.html?cp=2_1_1_0_1_24.  

[bloobird0]

hello,

I added the code from the errata that you sent me and it looks to solve my issue, I have to test further but from what I see now it looks very good, thank you very much!

Yes some operation on float values are executed in the code.