Cannot pull down a GPIO pin which is shared with LED

[Quark]

Hi,

I added following code in saadc example code to set GPIO pin high/low and monitor it in the terminal. The pull up looks ok, but when I set it to low, the reading never goes down to 0. This happened on the shared pins with LED but not the others. Is there anything I need to set or turn off make these pin fully act as generic GPIO?

nrf_gpio_cfg_output(ARDUINO_7_PIN); nrf_gpio_pin_write(ARDUINO_7_PIN, 0);

[Jørgen Holmefjord]

Which board are you using? ARDUINO_7_PIN is defined as GPIO 18 on the nRF52832. Are you checking the pin named P0.18?

[Quark]

nRF52DK, P0.17~20 are shared with LED. When I set it to high, the reading is the same as VDD ~830, but when it is set to low, it keeps at ~111 and never goes to 1 or 2 as on GND, even if I pull high first then down.

[Jørgen Holmefjord]

The LEDs on the nRF52 DK are active low. You can disconnect the LED by cutting SB5-SB8 if you want to use the pins for other tasks.

[Quark]

OK, thanks!