Playground Bluefruit - NFC Support?

[kinkadius]

Looking around the documentation, it doesn't appear that there's support for using NFC on the NRF52840. The only reference I can find that mentions it is in bootloader changeling:
https://github.com/adafruit/Adafruit_nR ... og.md#0211

Has anybody else tried playing with the NFC support for this device?

[mikeysklar]

Interesting. I didn't realize NFC was baked into the nRF52840 hardware until you mentioned it. I don't see any examples on the Arduino/CircuitPython side.

We do have a note about NFC usage in the nRF52840 Feather guide. This might apply to the Playground Bluefruit.

https://learn.adafruit.com/introducing- ... -3014277-2

D2/NFC2: The D2 pin is uses the same pad as one-half of the NFC antenna pins. By default, the nRF52840 Feather ships with these pins configured for GPIO mode, which is done by writing a value to the UICR flash config memory. If you wish to use NFC, you will need to erase the UICR memory which requires erasing the entire chip, and you will need a Segger J-Link to reflash the bootloader and firmware.

There is a github project using it's own nRF52 customized board that is worth checking out on this topic.

https://github.com/cmdwtf/Odiin

[kinkadius]

Interesting. I didn't realize NFC was baked into the nRF52840 hardware until you mentioned it. I don't see any examples on the Arduino/CircuitPython side.

We do have a note about NFC usage in the nRF52840 Feather guide. This might apply to the Playground Bluefruit.

https://learn.adafruit.com/introducing- ... -3014277-2

D2/NFC2: The D2 pin is uses the same pad as one-half of the NFC antenna pins. By default, the nRF52840 Feather ships with these pins configured for GPIO mode, which is done by writing a value to the UICR flash config memory. If you wish to use NFC, you will need to erase the UICR memory which requires erasing the entire chip, and you will need a Segger J-Link to reflash the bootloader and firmware.

There is a github project using it's own nRF52 customized board that is worth checking out on this topic.

https://github.com/cmdwtf/Odiin

Oof, erasing UICR memory would be a bummer, what do you think it would take to use NFC with the boot loader that was given? Would I need to modify the bootloader?

[mikeysklar]

You will need to use a Segger J-Link to reflash out bootloader and set the UICR NFC configuration (register 0x20C). Our bootloader should be fine to reupload as this is only a register setting. There is a little more described here:

https://jimmywongiot.com/2019/08/19/man ... cr-region/