nrf52 enabling gpio on nfc pins

[[email protected]]

Hi 

I have developed a PCB that will be used to control some sensors. The pins NFC1 and NFC2 are intended to be used as GPIOs. However, the default processor settings configure these pins as "NFC-pins". How can I change that? I couldn't figure it out with the online documentation and the processor datasheet. Note, that I use Segger Embedded Studio for the code development. 

Thanks for your help

[Håkon Alseth]

Hi,

 

This is done by setting the NFCPINS register (note that the UICR is flash, so the NVMC is used to write to this area!). If you add the preprocessor define "CONFIG_NFCT_PINS_AS_GPIOS" (add under project settings -> "Preprocessor" -> "Preprocessor definitions"), you should be able to use these NFC pins as normal GPIOs. This code snippet is shown in the system_nrf52.c file.

If using the nRF52-DK, you'll need to place resistors mounted on R25/R26 to R27/R28, as explained here: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52/dita/nrf52/development/nrf52_dev_kit/hw_nfc.html?cp=2_1_4_5_10

 

Best regards,

Håkon

[cjh39]

The link above does not work anymore..

Im using a nrf52840 , Segger with the nrf SDK.

How do I use the NFC pins as GPIO ? There must be a simple solution to this.

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