Saturday, July 6, 2024

Custom RDM6300 firmware RFID reader/writter for EM4100, T5577 ICs

So I bought an RDM6300 RFID card/tag reader and realized that it cannot write tags. Thus, I have decided to add writing capability and to include support for other RFID chips. Original firmware supports only chips that uses the EM4100 protocol but by replacing it with a custom firmware, new protocols can be added.

RDM6300 v2 uses the C8051F330 microcontroller from Silabs which is quite old and has only ~7.5kB of program memory that limits how much the functionality can be expanded. If there is interest, I might make a custom board with a more modern microcontroller and also include a PCB coil to reduce the cost of the RFID module.


RFID frequency: 125kHz
RFID mode: read/write
Supported ICs:
  • EM4100
  • T55xx (e.g. T5577, Blue Trinket tags)
Bit rates: RF/16, RF/32, RF/64
Supported encoding: Manchester
Supported Sequence Terminators (ST):
  • Default (ST bit=0)
  • ST bit=1 and X-Mode=0
  • ST bit=1 and X-Mode=1: not supported as it didn't provide reliable results
 Interface: UART, 115200, 8-bit