No wake up after LPCOMP set in SYSTEM OFF nrf52 SDK12.1

RE: No wake up after LPCOMP set in SYSTEM OFF nrf52 SDK12.1

Sergy — Tue, 06 Dec 2016 20:06:40 GMT

Thanks very much Sigurd, that was the problem indeed!

RE: No wake up after LPCOMP set in SYSTEM OFF nrf52 SDK12.1

Sigurd — Mon, 05 Dec 2016 15:06:39 GMT

Hi,

Before going to System OFF mode, you will need to wait for the LPCOMP to be ready. In the product specification its stated that:

After a start-up time of t_LPCOMP,STARTUP the LPCOMP will generate a READY event to indicate
that the comparator is ready to use and the output of the LPCOMP is correct

So change your code to:

nrf_drv_lpcomp_config_t config = NRF_DRV_LPCONF_DEFAULT_CONFIG;
config.hal.detection=1;
config.hal.reference=1;
config.input = NRF_LPCOMP_INPUT_2;
// initialize LPCOMP driver, from this point LPCOMP will be active and provided
// event handler will be executed when defined action is detected
err_code = nrf_drv_lpcomp_init(&config, wakeUp);
APP_ERROR_CHECK(err_code);
nrf_drv_lpcomp_enable();
while(NRF_LPCOMP->EVENTS_READY == 0);
NRF_LPCOMP->EVENTS_READY = 0;
sd_power_system_off();

RE: No wake up after LPCOMP set in SYSTEM OFF nrf52 SDK12.1

Sergy — Mon, 05 Dec 2016 12:29:30 GMT

I have NRF_LOG printouts and also a buzzer to indicate that the system is startup. Basically it doesnt startup again.

RE: No wake up after LPCOMP set in SYSTEM OFF nrf52 SDK12.1

Sigurd — Mon, 05 Dec 2016 12:25:00 GMT

How are you detecting that the wake up is triggered/not triggered? When the system wakes up from System OFF mode, it gets reset.