Can ST25RFAL002 rfalListenStart handle 10 bytes NFCID?

[lMa.1]

I'm using `rfalListenStart` in ST25RFAL002 with ST25R3916 to emulate an ISO 14443 Type A card with 10 bytes long UID. I've noticed that `rfalNfcDiscover` can work with 10 bytes long UID, but `rfalListenStart` cannot as the code goes:

    switch(confA->nfcidLen) {
 
    case RFAL_LM_NFCID_LEN_04:
 
      st25r3916ChangeRegisterBits(
 
        ST25R3916_REG_AUX, ST25R3916_REG_AUX_nfc_id_mask, ST25R3916_REG_AUX_nfc_id_4bytes);
 
      break;
 
 
 
    case RFAL_LM_NFCID_LEN_07:
 
      st25r3916ChangeRegisterBits(
 
        ST25R3916_REG_AUX, ST25R3916_REG_AUX_nfc_id_mask, ST25R3916_REG_AUX_nfc_id_7bytes);
 
      break;
 
 
 
    default:
 
      return ERR_PARAM;
 
    }

and the Auxiliary definition register in the datasheet shows only 4 bytes/7 bytes/RFU are available. I'm a little confused, is there some limitation on emulating 10 bytes long UID, or i'm misusing it? 😳 

[Ulysses HERNIOSUS · Accepted solution]

Hello,

ST25R3916 and ST25R3916B cannot emulate 10 byte UIDs with their built-in automatics. Theoretically software could do such using lower level frame interface but it will be quite a challenge to meet the required timings: As software would need to handle

• Read the interrupt status
• Read the FIFO
• Inspect the bytes, prepare an answer.
• Write the answer into FIFO
• Trigger transmit command

And all that in less than ~86us.

There is no requirement for a listener to support a specific NFCID1 size. But as a poller one needs to be able to handle any NFCID1 size.

In reality I have never seen an NFCID1 of 10 bytes (except for NFCID1s created by test tools). What is your interest in 10 bytes UIDs?

Best Regards, Ulysses

[lMa.1]

Thanks for the explanation. I've encountered some car keys in real life using NFCID1 of 10 bytes, sorry I can't share more information with you.