selecting NFC pins (0.9 and 0.10)

[Eyal_Gal]

So i have a custom nrf52840 board that i'm working on with SDK 15.2

I want to use the NFC as GPIO.

According to the docs i need to set in the sdk_config.h CONFIG_NFCT_PINS_AS_GPIOS.

It didn't work. i was sure i was doing something wrong so i investigated.

CONFIG_NFCT_PINS_AS_GPIOS define is checked in 2 places:

nRF5_SDK_15.2.0_9412b96/modules/nrfx/mdk/system_nrf52.c
nRF5_SDK_15.2.0_9412b96/modules/nrfx/mdk/system_nrf52840.c

from which only 1 is used in my project, the one with nrf52840.

So i stopped compilation in pre compilation using -E switch in CFLAGS. I could not find CONFIG_NFCT_PINS_AS_GPIOS in the .c.o output file. So i checked further and it seems like sdk_config is not even included in this file or it's header.

Chgecking this forum someone mentioned he added `-DCONFIG_NFCT_PINS_AS_GPIOS` to his CFLAGS, this makes sense as it will define CONFIG_NFCT_PINS_AS_GPIOS in all files including this one, the question is why is the sdk_config not included and if it's supposed to be, why does the docs states to include CONFIG_NFCT_PINS_AS_GPIOS in the sdk_config.h when its clearly not used anywhere at all.

[Jørgen Holmefjord]

Hi,

Can you post a link to the documentation where it states that CONFIG_NFCT_PINS_AS_GPIOS should be set in sdk_config.h? 

The references I can find to this config is in the nRF52840 DK (and other DKs) user-guide, where it says:

NFC can be disabled and GPIOs enabled by defining the CONFIG_NFCT_PINS_AS_GPIOS variable in the project settings. The way of doing this depends on the Integrated Development Environment (IDE)/toolchain in use:

• When using SEGGER Embedded Studio, select Project > Edit Options > Code > Preprocessor > Preprocessor Definitions and add the CONFIG_NFCT_PINS_AS_GPIOS variable.
• When using Keil, go to Project > Options for Target > C/C++ > Preprocessor Symbols > Define and add the CONFIG_NFCT_PINS_AS_GPIOS variable.

If you are using GCC, adding the symbol to CFLAGS in the Makefile is the correct approach.

Best regards,
Jørgen

[cjh39]

Ive tried this and it does not work. How do I set this in Segger so I can use the NFC pins as GPIO / SPI..

Ive added #define CONFIG_NFCT_PINS_AS_GPIOS 1 to the sdk_config.h and also I added the CONFIG_NFCT_PINS_AS_GPIOS here

When I check the nrfjprog --memrd 0x10001000 --n 512, Im getting all F's

How do we turn them off in Segger using the nrf SDK ?