Input buffer connected in nrf_gpio_cfg_output() of the SDK

[Ronnie Bajwa]

My understanding so far is that the input buffer of GPIO is disconnected by default and we can keep it disconnected for saving power when the pin is configured as output. Is there a reason why nrf_gpio_cfg_output() in the latest SDK connects the input buffer while configuring the pin as output? Here's the code for reference:

static __INLINE void nrf_gpio_cfg_output(uint32_t pin_number) { NRF_GPIO->PIN_CNF[pin_number] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) | (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos) | (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos) | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) | (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos); }

Thanks in advance!

Ronnie

[Hung Bui]

Hi Ronnie,

Seems that it is a bug in our SDK. I will report this internally for a bug fix. Input buffer should be disconnected when the pin is not configured as input.

Thanks for pointing out.

[Eliot Stock]

It's still that way in SDK 8.0.0 and this answer to roughly the same question gives a reason they may have left it that way;

devzone.nordicsemi.com/.../