P0.08 not working with nRF51822 QFAC

[Guillaume Levant]

Hi,

I have a PCB with a nRF51822 QFAC A1 onboard, and I wrote a firmware with mbed for this PCB in which P0.08 is supposed to be set to 1 during the initialization and is never set to 0 after. But when I test the firmware this GPIO is always at 0. I tried to find a short circuit but according to my multimeter the resistance betwen p8 and Vss is 33kOhms, which is correct according to the schematic of my PCB. Is this pin has a specific function and could not be set to 1 ? I didn't find any information confirming this in the datasheet.

I use softdevice s110 7.3.0

Best regards,

Guillaume

[MartinBL]

How exactly do you know that the pin is always at zero? Have you measured the voltage with a multimeter or do you just assume it is always zero because EN on U8 is never high? Without knowing what U8 is, it seems strange to me that you have a button that when activated connects U8-EN to 4.1V, and yet you have a voltage divider from the nRF51 EN-net dividing the pin voltage down to two thirds of the nRF51s supply voltage, which I assume is 3V3?