GPIO not Ground

[WesC]

I am using an nRF52 dev kit.  I have loaded the pca_app_hts_pca10040_s132  example into the board.  I only added these lines of code

nrf_gpio_cfg_output(ARDUINO_9_PIN);
nrf_gpio_cfg_output(ARDUINO_10_PIN);
nrf_gpio_cfg_output(ARDUINO_11_PIN);

nrf_gpio_pin_clear(ARDUINO_9_PIN);
nrf_gpio_pin_set(ARDUINO_10_PIN);
nrf_gpio_pin_clear(ARDUINO_11_PIN);

when i look at the pins.  Arduino_Pin 10 is 3 V and Arduino_Pin 11 is GND,

but Arduino_pin9 is .355V

i have tried 2 different board with the same result.

to verify i have the correct pin, i changed _clear to _set on pin 9 and the pin will goto 3V

what am i missing?  

[Vidar Berg]

Hello,

You will measure a voltage drop on the pad when setting this output pin low because it is connected to LED 4 (ARDUINO_9_PIN == P0.20). The silkscreen print on the backside of the DK shows the LED circuit.

[WesC]

Thanks.  I knew i was missing something simple.  Even though l looked at the DK schematic, i clearly missed it.  thanks again