P0.07 Input SENSE_LOW doesn't work

[John]

nrf_gpio_cfg(7,
			NRF_GPIO_PIN_DIR_INPUT,
			NRF_GPIO_PIN_INPUT_CONNECT,
			NRF_GPIO_PIN_NOPULL,
			NRF_GPIO_PIN_S0S1,
			NRF_GPIO_PIN_SENSE_LOW);

For some reason the microprocessor will not wake when P0.07 is pulled low.  I have an external 10kOhm pullup so there is no need to configure the internal pullup.  If I change from P0.07 to another pin it works fine.  I have tested this on the nRF52-DK as well as my own custom board.  I am currently using SDK 15.3

[Kenneth]

Is it possible that your project have for instance enabled uart (for debugging or similiar) and that pin 7 is used by this?

Kenneth

[John]

Kenneth,

That's where I started since the DK board has it connected as a CTS signal for the Segger.  I removed all things UART and am still having issues.  Not sure why this is not super easy to do.

John

[Kenneth]

I suggest to try and fail a bit, maybe simplify the application to just test simple functionality, e.g. can you control the pin as a normal output?

Kenneth

[John]

Kenneth,

as far as a gpio goes, P0.07 works as expected.  It is currently connected to an open drain CHRGb signal with a pull up of course.  Once the device is turned on I can wiggle the output of the CHRGb signal and the nRF reads it just fine!  So weird.  It physically will not allow the device to wake upon the signal being pulled low.  I'm haveing to make a few board changes anyways so I went ahead and changed the pin to P0.14 which works as expected.  It would be nice to understand why this does not work.  I've been using nRF since the 8002 so I'm really familiar with their devices.  Let me know if you have any other thoughts.

[Kenneth]

The only thing I can think of is that P0.07 is configured by a different peripheral also, most commonly used by NRF_LOG module if UART backend is enabled (see back of nRF52-DK). You can in any case change the pin number defined by the CTS pin  to check if this is indeed the case.

Kenneth