How to exit System OFF based on timer

[usmanmehmood55]

I am exploring the nRF52832 using nRF52-DK for a low powered BLE device. And for that I am making the System OFF example as my basis for measuring currents of different features and software flows. 

The chip can be woken up from System OFF using a GPIO, which is configured as

nrf_gpio_cfg_input(NRF_DT_GPIOS_TO_PSEL(DT_ALIAS(sw0), gpios), NRF_GPIO_PIN_PULLUP);
nrf_gpio_cfg_sense_set(NRF_DT_GPIOS_TO_PSEL(DT_ALIAS(sw0), gpios), NRF_GPIO_PIN_SENSE_LOW);

In the example the sleep mode is selected as

struct pm_state_info info =
{
    .exit_latency_us  = 0,
    .min_residency_us = 0,
    .state            = PM_STATE_SOFT_OFF,
    .substate_id      = 0,
};

Which is then passed as

pm_state_force(0u, &info);

And finally it goes into System OFF mode with

k_sleep(K_SECONDS(SLEEP_S)); // SLEEP_S is 5

After 5 seconds I expected it to wake up, but it never does. It wakes up from the GPIO just fine, but not from the timer.

Is there a proper way to configure this?

Any help would be greatly appreciated.

Thanks in advance 

[Hakon]

Hello,

After 5 seconds I expected it to wake up, but it never does. It wakes up from the GPIO just fine, but not from the timer.

Waking the CPU with a timer doesn't work, because the RTC will be turned off in system off. You will need to have an external interrupt based timer to be able to wake it up like that.

[usmanmehmood55]

Thank you Hakon I realized that too, just this morning when I came across this thread.