ST25R3916B Read NFC-A Tags Custom Firmware

[joeyhk2020]

Hi,

So for my custom application I am currently testing with the NFC08A1 board and need to write my own firmware to manage the ST25R3916B IC's on the board. I have been able to implement AP2P between two boards but have not been able to get the board to read NFC-A/any tags yet. Memory is currently setup as in the attached image (I have attempted to set the required registers, but these may be incorrect/I may be missing some). My implementation currently attempts to read by first resetting RX gain, turning NFC initial field on (and wait for the relevant IRQ), clear FIFO, then Transmit REQA.

I have tried dissecting the RFAL library but this would take too long so I was wondering if anyone had a working solution.

Thanks in advance!

[Brian TIDAL]

Hi,

ready to use demos are available inside the ST25 embedded NFC library package (including a peer 2 peer demo). I would recommand to base your custom application on one of those demo.

Rgds

BT

[joeyhk2020]

Hi Brian,

The resource isn't available for the ST25R3916B chip on the NFC08A1 board. Would appreciate help directly working with the IC and what I'm missing in my setup/execution. My code for P2P is already working, but the issue is that I am currently unable to get the device to read NFC-A type (or any) tags.

[Brian TIDAL]

Hi,

STSW-ST25R016 package in ST25 embedded NFC library supports both ST25R3916 and ST25R3916B.

Which NFC-A tag do you use (manufacturer an model)?

Rgds

BT

[joeyhk2020]

Hi Brian,

Actually since my original posting I had managed to have my reader read NFC-A type tags. However, I'm having an issue now where when I attempt to use another reader in card emulation mode (Currently both using NFC08A1 boards for the initiator and target), the target is able to receive a message but the reader is not able to detect a response back. My application in the end will not be following NFC protocols/standards so I am not utilizing the RFAL library for this purpose. 

Once the target receives message, my current attempt at responding is to: Clear FIFO, load response into FIFO (and set FIFO TX length), turn on NFC response field, and then transmit with CRC. However, even with experimenting with different register configurations I have not had success in responding back to the reader so far.

(Also not sure if I should start a new thread for this)

Thanks,

Joey

[Brian TIDAL · Accepted solution]

Hi Joey,

if I understand well:

• you are not using the Card Emulation mode but rather the Active Peer to Peer (AP2P) mode where the field is alterning between the initiator and the target
• you don't need the full communication stack (LLCP, SNEP, etc.)

The ap2p_proprietary project from  ST25 embedded NFC library (STSW-ST25R016 package) provides an example of AP2P communication between 2 X-NUCLEO-NFC08A1 boards. It uses only the NFC-DEP Data Exchange Protocol but no LLCP/SNEP etc. You can either use it directly in your project or simply spy the SPI transactions to see how the registers are configured during a data transceive.

Rgds

BT