Long Press to Wake-up

[sara]

Hello,

Is there any methods to implement the "long press wake-up"? Pressing the button for 3 seconds to let device enter sleep mode and pressing the same button for 3 seconds to wake it up.

Already defined the wake-up gpio in "sleep_mode_enter()" function as below. The question is that how to measure the time when the device wake-up from the sleep mode?

[SDK12, nRF52]

 static void sleep_mode_enter(void)
{
		uint32_t err_code;
	
		//
		LEDS_OFF(LEDS_MASK);
	
		// init wakeup gpio
		nrf_drv_gpiote_in_uninit(5);

		nrf_drv_gpiote_in_config_t power_btn_config =   GPIOTE_CONFIG_IN_SENSE_HITOLO(false);
		power_btn_config.pull = NRF_GPIO_PIN_PULLUP;
		err_code = nrf_drv_gpiote_in_init(5, &power_btn_config, NULL);
		APP_ERROR_CHECK(err_code);
		nrf_drv_gpiote_in_event_enable(5, true);

		nrf_delay_ms(500);

        // 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);
}

Thanks.

[endnode]

Hello Sara,

If you mean SYSTEM OFF by your "sleep" then NO, the only wake-up mechanism in your situation is simple GPIOTE level change, there is no clock running in SYSTEM OFF so obviously you cannot detect "long" press. If you need it for user experience then you can of course fake it by going back to OFF mode if the GPIO line doesn't hold "pressed" state long enough after nRF5x wakes up.

CHeers Jan

[sara]

Understood, thanks for your help.

[Hung Bui]

@Sara: as endnode wrote, you don't have any timer when you are in SystemOFF so the chip won't know if it's a long press or not. But if you put the systemON mode with CPU off, you can still keep the RTC running and detect if it's a long press or not. SystemON+ RTC running may cost you some uA extra, should be less than 5uA as far as I recall.

[sara]

Hello Hung Bui, I got it, but how to let the system in system ON mode but CPU off? Thanks.

Sara

[Hung Bui]

You can simply put the CPU to sleep, by calling __WFE function. Please have refer to the main while loop in our rtc example in \examples\peripheral\rtc or if you use Softdevice, please use power_manage() function as in the main loop of our ble examples.