ISO14443-4(RATS) in mifare desfire

0
votes

I'm trying to initial mifare desfire ev1 with my mfrc522 based reader.ISO14443-3 is done successfully and I select PICC successfully and read 7 byte UID and SAK correctly.As I know after completing anti-collision and select processes and receiving valid SAK(0x20) I must perform ISO14443-4 commands.Then I send RATS command to the PICC:

PCD->PICC RATS:  '0xE0','0x50','CRC_MSB','CRC_LSB'

but PICC does not answer with SAK(I receive nothing),actually seems buffer is not big enough.

1
cnfcsmartcardrfidmifare
For RATS command you will receive an ATS, while SAK is the response for the selection request - Paul Bastian

1 Answers

1
votes

ISO 14443-3 CRC_A is transmitted least-significant-byte-first (little-endian) -- see Annex B.

The correct RATS should be:

PCD->PICC RATS:  '0xE0','0x50','CRC_LSB','CRC_MSB'

Which means:

PCD->PICC RATS:  '0xE0','0x50','0xBC','0xA5'

for your particular FSDI/CID.

Good luck!