GPIO value after wake up from GPIO

RE: GPIO value after wake up from GPIO

BasileC — Tue, 18 Sep 2018 12:04:34 GMT

Yes my main problem was the debug mode issue, it's solved now.

But a gpio init with NRF_GPIO_PIN_NOPULL should keep the same state at start and instead it changed it.

Anyway thanks for your help Kenneth !

RE: GPIO value after wake up from GPIO

Kenneth — Mon, 17 Sep 2018 18:53:06 GMT

Not sure if I understand the problem, but there is no need to re-init the GPIO after a system OFF, so you may just have a check RESETREAS register if reset reason is from system OFF then skip init of GPIOs?

Best regards,
Kenneth

RE: GPIO value after wake up from GPIO

BasileC — Mon, 17 Sep 2018 13:02:08 GMT

Didn't knew about this, i tried and it works indeed but only if my Gpio is not initialized.

For example :

nrf_gpio_pin_clear(EXTINT_GPS_PIN);

sd_power_system_off();

// System is now OFF

During my start-up phase i got init_gpio() called with in :

nrf_gpio_cfg_input(EXTINT_GPS_PIN, NRF_GPIO_PIN_NOPULL);

If i comment the last line, my gpio got the right state (value = 0) but if i initialize it I got value = 1.

It's a known issue ?

However thanks i didin't know for the gpio debug issue.

RE: GPIO value after wake up from GPIO

Kenneth — Mon, 17 Sep 2018 11:43:23 GMT

Hello,

The NRF_GPIO peripheral should maintain configuration, however if you have peripheral (e.g. TWI, UART etc) controlling the pins, then during wakeup from system off it will fall back to the actual NRF_GPIO configuration. So make sure that before you go to sleep (system OFF) that you set NRF_GPIO pins to the state you want them to have when wakeup.

Also make sure you are not in debug mode during sleep, because of this errata:
http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.Rev1.errata/anomaly_832_81.html#anomaly_832_81

Best regards,
Kenneth