Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

Johnny Nguyen — Wed, 05 Mar 2025 01:51:01 GMT

In the sample, you can see that process in carrier_prepare, tnep_ch_request_prepare, and the callbacks in the nfc_tnep_ch_cb struct.

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

dBest — Wed, 05 Mar 2025 00:34:32 GMT

The simplified flow you listed looks to be the Static Pairing method, if I'm not mistaken. I am trying to do the TNEP negotiated handover method. Do you have a simplified flow for that?

I've been able to get a static pairing demo working, because it's just been a simple matter of parsing the NDEF message and using the OOB functions, and initiating a Bluetooth scan.

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

Johnny Nguyen — Wed, 26 Feb 2025 22:08:44 GMT

Hi Derrik,

Sorry I’m just now getting back to this. For posterity and record keeping, I am consolidating our e-mail chain to this DZ case.

The high-level overall flow is:

The Central NFC sample initializes the NFC and waits for a Type 2 or Type 4 NFC Tag to appear in the field.
When a tag is detected, the read and parses its content.
The tag content should include Connection Handover messages and records, which contain the data required to initiate pairing, including the Bluetooth LE address of the peripheral device.
After reading the tag or exchanging data over TNEP (Tag NDEF Exchange Protocol), the central device starts scanning for the specific Bluetooth LE address obtained from the tag.
Once the advertising device with the matching address is found, the central device initiates the pairing process.

Our initial correspondence was around nfc_tnep_poller_svc_select potentially hanging up and wanting to add logs to the poller implementation. Looking at the log you sent earlier, maybe it’s not getting hung up where I originally thought it was, digging into the library could be an XY problem.

Do any callbacks in the connection handover service struct you init ever get called in your application? Are you getting the OoB data across to apply to the central’s scan filter?

I see the capability container being scanned, but I’m not seeing any logs that would be in the application space beyond just reading/parsing the capability container.

The simplified flow should be:

Detect and read the NFC tag
Read and parse the Capability Container
Read the NDEF file
Parse the NDEF message for Connection Handover records
Extract OOB data (including the Bluetooth LE address, and a key to use in place of a pin code)
Use the Connection Handover service to process this data and initiate Bluetooth pairing

(More info at NFC TNEP Connection Handover)

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

Kenneth — Wed, 26 Feb 2025 15:21:37 GMT

Sorry no. Some background: The main reason we introduced support for an NFC reader/writer chip was to verify our NFC Tag solution. It provide a complimentary sample for the NFC tag samples available in the SDK. The ST25R3911B was chosen because it supports all the modes that were required for testing the Nordic Tag. So unfortunately we have very little information about the reader/writer in this case.

Kenneth

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

dBest — Tue, 25 Feb 2025 22:39:56 GMT

Do you have any documentation or block diagrams on the Nordic implementation of the TNEP API (beyond what is already on the link I posted)?

RE: Bluetooth Sample central_nfc_pairing with PN7160 NFC Controller

Kenneth — Tue, 25 Feb 2025 13:01:19 GMT

Hello,

Unfortunately I am not much at help on this one. I wanted to take a look at the application note from NFC forum, which describes how the exchange is occurring, but it's behind a paywall, so not able to look into the details there either: https://nfc-forum.org/build/specifications/bluetooth-secure-simple-pairing-using-nfc/

Likely getting a board with the ST25R3911B is a good idea for comparison :
https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/libraries/others/st25r3911b_nfc.html#st25r3911b-nfc-readme

Kenneth