How to sniff RFID reader to ISO 14443 tag data transmission using OpenPICC

1. configure OpenPCD to send data continuously

• connect USB debug cable to RS232_CMOS connector on OpenPCD - black wire is Pin 1
• cu -l/dev/ttyUSB0 -s115200 (debug terminal - where ttyUSB0 is the debug cable. You can find 'cu' in the uucp packet. Make sure that your current user is also in the group 'uucp' to use this software )
• power cycle OpenPCD again - OpenPCD boot message appear
• press 'A' on debug terminal to enable continuous long packet transmission by OpenPCD - green LED turns on continuously in return

2. compile openpcd_test:

• mkdir openpicc
• cd openpicc
• svn co http://svn.openpcd.org/trunk/host/
• svn co http://svn.openpcd.org/trunk/firmware/
• cd host
• make opcd_test
• mv opcd_test opicc_test
• plug OpenPICC into USB port
• sudo ./opicc_test -L

3. Configure OpenPICC via USB debug cable:

• plug the debug cable into OpenPICC - black wire towards jumper socket in top right
• press '}` several times to decrease the sampling clock divider to the lowest value
• press 'd' till SSC-Mode is set to '5'
• press 's' to start sampling
• press 'a' to stop sampling
• analyse /tmp/opcd_samples for sampled data (see example file)

4. Decode the sniffed data:

• wget http://www.openpcd.org/dl/openpicc/decode_openpicc.c
• gcc -O2 -o decode decode_openpicc.c
• ./decode /tmp/opcd_samples
• Example output:

  Y
  Z[07]0 Z[07]0 Z[07]0 Z[07]0 Z[07]0 Z[07]0 Z[07]0 Z[00]0  [11]1   ==0x00
  X[07]1 X[07]1 X[07]1 X[07]1 X[07]1 X[07]1 X[07]1 X[07]1 X[07]1   ==0xFF
  X[07]1 X[11]0 Z[07]0 Z[00]0  [11]1 X[11]0 Z[07]0 Z[00]0  [12]1   ==0x11
  X[00]0  [14]1 X[11]0 Z[07]0 Z[00]0  [11]1 X[11]0 Z[00]0  [11]1   ==0x22
  X[07]1 X[07]1 X[11]0 Z[00]0  [11]1 X[07]1 X[11]0 Z[00]0  [11]1   ==0x33
  X[12]0 Z[00]0  [10]1 X[11]0 Z[07]0 Z[00]0  [11]1 X[00]0  [16]1   ==0x44
  X[06]1 X[00]0  [15]1 X[00]0  [16]1 X[00]0  [14]1 X[00]0  [15]1   ==0x55
  X[00]0  [16]1 X[06]1 X[12]0 Z[00]0  [11]1 X[06]1 X[00]0  [15]1   ==0x66
  X[00]0  [16]1 X[00]0  [14]1 X[11]0 Z[00]0  [12]1 X[10]0 Z[08]0   ==0x4A
  Z[07]0 Z[00]0  [11]1 X[07]1 X[11]0 Z[00]0  [11]1 X[10]0 Z[08]0   ==0x4C
  CRC OK