Problem to using p0.18(RESET Pin) for GPIO

[butumout]

I'm using nrf52833 on custom board.

And I need to using RESET pin to GPIO for battery charging detection.

I found CONFIG_GPIO_AS_PINRESET is configuration RESET pin,

and if I undefined CONFIG_GPIO_AS_PINRESET, p0.18 pin will be working GPIO.

But, many of case was failed.

I think,

If I undefined CONFIG_GPIO_AS_PINRESET,

MCU was nothing to handling NRF_UICR->PSELRESET register.

But NRF_UICR->PSELRESET registor still configuration like RESET pin(like dummy data ).

So, even if CONFIG_GPIO_AS_PINRESET is undefined, MCU still working p0.18 pin is configuration by RESET pin.

That's why I think, it's need to setting NRF_UICR->PSELRESET register to disconnect(connect bit to set '1') when CONFIG_GPIO_AS_PINRESET is undefined.

[SwRa]

Hi,

Could you try to do a full chip erase and then flash the firmware.? To use the RESET pin as GPIO, you need to first compile without defining the CONFIG_GPIO_AS_PINRESET, perform a full chip erase and then flash the code again. A full chip erase is necessary to erase the UICR or else, as you have observed, pin reset will remain enabled even after undefining CONFIG_GPIO_AS_PINRESET.

Regards,

Swathy