Peer to peer nfc possible? Field strength available?

[HurleyResearch]

We're building small robots/toys that work with each other.

Would it be possible to use the nfct on two devices with nRF52840 to communicate between each other?

Also is there any way to get information about field strength?

Of course this is not standard usage of nfc but if possible it would be nice to have some peer to peer detection at least, then near field ranging even better, then full communications best.

Any ideas appreciated, thanks!

[endnode]

Nooooooo (search the forum before you ask).

[HurleyResearch]

naturally I searched, but didn't find anything... can you suggest a search phrase that would get me a better answer?

[endnode]

In any question related to NFC reader capabilities you can read that chip has no means how to generate 13.56MHz field so it can be only PICC (tag) never PCD. As consequence it can be neither reader nor part of peer-to-peer communication.

Actually I put NFC phrase into the search box and these are relevant Q&S just from the first page of results on this forum:

• devzone.nordicsemi.com/.../
• devzone.nordicsemi.com/.../
• devzone.nordicsemi.com/.../
• devzone.nordicsemi.com/.../

[HurleyResearch]

huh... thanks for the quick responses btw. I'm reading in the nRF52840 product spec, on page 475...

"41.1 Overview The NFCT peripheral contains a 13.56 MHz AM receiver and a 13.56 MHz load modulator with 106 kbps data rate as defined by the NFC Forum."

And there's all sorts of talk about transmitting, not just receiving. Are we talking about the same chip or am I missing something else?

[endnode]

Oh yes. All that is related to internal Tx/Rx representation which is running on top of EasyDMA and NFCT registry. But when you read how actual communication is done on HW level it's just modulation while listening to the field. This i how "tags" (or better PICC = contactless "cards") work to receive data and send something back. But if you read somewhere how NFC peer-to-peer mode works you need to have field driving capability on both sides. So this is kind of no-go, to talk nRF52<=>nRF52 over NFC means that you need some additional HW on top of at least one board.

[HurleyResearch]

indeed, your answer plus some more reading, and it all makes perfect sense, thanks.