RE: regarding waking up device from sleep mode

Sigurd — Mon, 07 May 2018 12:52:38 GMT

Hi,

[quote userid="69288" url="~/f/nordic-q-a/34118/regarding-waking-up-device-from-sleep-mode"]But when we are using same implementation to shut down device {sd_power_system_off()} the device goes to sleep but the device does not wakes up. are there any configuration setting which we need to do so that device exits sleep mode.[/quote]

When in System OFF mode, the device can be woken up through one of the following signals:

The DETECT signal, optionally generated by the GPIO peripheral
The ANADETECT signal, optionally generated by the LPCOMP module
The SENSE signal, optionally generated by the NFC module to “wake-on-field”
A reset

Try to configure the pin you want to use to wake the chip up with like this:

nrf_gpio_cfg_sense_input(PIN NUMBER, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);

This will generate the DETECT signal when the pin goes from high to low.

Note that in some examples in the SDK, we use the function bsp_btn_ble_sleep_mode_prepare() to do this. It will by defualt configure button 1 to wake the chip up when pressed.

static void sleep_mode_enter(void)
{
    uint32_t err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}