How to debug NFC APDUs

[Mik]

Hi, we have implemented the experimental_writeable_ndef_msg example from SDK12.2 with Nordic NRF52 on a custom board. Reading the NDEF Message works fine with smartphones (Android and IOS11 with Iphone 7). We have used NFC in previous Projects together with a PC Smartcard Reader with PC/SC interface. Unfortunatly the Cardreader from Identive (uTrust3700F) can't read the NRF52. Sending the Application select APDU (00 A4 04 00 07 D2 76 00 00 85 01 01) results in the response 69 82 (even with adding the Le byte 00 at the end of the APDU). We do have an other PC/SC NFC Card Reader (ACR122) and sending the APDU works fine. I would like to find out the diffreneces in sending the APDUs. How can i change the logging in NRF52 to get the received APDUs and the send responses (e.g. as seen in this question [...])(devzone.nordicsemi.com/.../) It's very important for us to get the Identiv reader working, as we have many readers sold to customers. Thanks in advance!

[Hung Bui]

Hi Mik,

You mean you want to see deeper log level like the "HAL_NFC:DEBUG: 02 00 A4 04 00 07 D2 76 00 00 85 01 01 " in the other case ?

You should first enable logging in the sdk_config file, remember to enable logging in both nRF_LOG and nRF_NFC. Change the default logging level to DEBUG instead of Info. Logging with RTT is suggested as I found that when I enable logging with UART i have problem communicate with NFC, could be some timing issue.

Then you can print out the RX data (m_nfc_rx_buffer) when you receive RX event (look for the place where we print "Rx fend" in hal_nfc_t4t.c

[Mik]

Hi Hung Bui, thanks for the comment and it worked fine to get the rx_buffer. I've just added the NRF_LOG_HEXDUMP_DEBUG() at the suggested line and i can see the difference between the two readers. I would also like to see the tx, but there is no m_nfc_tx_buffer. What would you suggest?

[Hung Bui]

For TX, you can try adding log in hal_nfc_send(), the buffer is in p_data with data_length. But I would assume it is exactly what the application provides.