RE: NFC Callback Event Payload Details

Mark J — Tue, 19 Jan 2021 16:53:06 GMT

Thanks for the reply. The Android dev links may provide some good info. I will start by logging the payload for NFC events (NFC_T2T_EVENT_DATA_READ and NFC_T2T_EVENT_STOPPED) using the Nordic example (nfc_url_record) and look for distinguishing and repeatable payload components when swapping reader devices (ie Smartphones). I will use my nrf52 DK for this. This might be the fastest option to determining if there is something that we can (possibly) use. If the payload contents look promising, I can dig further into protocol details.

Thanks,

Mark J

RE: NFC Callback Event Payload Details

Jørgen Holmefjord — Tue, 19 Jan 2021 16:16:27 GMT

Hi,

There is some information in nfc_t4t_event_t and nfc_t2t_event_t about the events and available parameters.

[quote user=""]We would like to understand if there is any distinguishing Id for the reading/scanning device that can be read so that we can setup an NDEF payload based on the reader/scanner Id. Ideally - this info is available for the NFC_T2T_EVENT_FIELD_ON orNFC_T4T_EVENT_FIELD_ON events.[/quote]

I cannot find any information about any point that the NFC reader/initiator will send its own ID to the tag during the selection procedure. If this is received at all, I think that it will only be available inside the closed-source NDEF library, and not to the application. The FIELD_ON events are generated when the tag detects a field. This happens before any data is exchanged, so there are certainly no ID available at this stage. I think that the initiator must write its own ID implicitly to the tag if this should work as you want, but I can check with the developers tomorrow if they have any other suggestions.

You can find some information about the NFC-A commands here, and the command flow here.

Best regards,
Jørgen