RE: Achieving low power states for GPIO pins

AndreasF — Thu, 18 Oct 2018 06:15:27 GMT

Hi John.

If you configure a GPIO pin as default, you should achieve the lowest power state if you used the function nrf_gpio_cfg_default(uint32_t pin_number);

In SDK 15.2, this functions sets the following configuration:

__STATIC_INLINE void nrf_gpio_cfg_default(uint32_t pin_number)
{
    nrf_gpio_cfg(
        pin_number,
        NRF_GPIO_PIN_DIR_INPUT,
        NRF_GPIO_PIN_INPUT_DISCONNECT,
        NRF_GPIO_PIN_NOPULL,
        NRF_GPIO_PIN_S0S1,
        NRF_GPIO_PIN_NOSENSE);
}

Where the following configuration is needed for low power:

NRF_GPIO_PIN_DIR_INPUT sets the pin as an input.
NRF_GPIO_PIN_INPUT_DISCONNECT disconnects the input buffer.
NRF_GPIO_PIN_NOPULL disables the pin pull-up resistor.

If you havnt used the pin for anything, this is how its already configured, as this is the reset configuration.

- Andreas