RRHFOEM04 Python Library

A Python Library for interfacing with the RRHFOEM04 RFID Reader.

CRC Calculation

The protocol uses CRC-16 for error detection with the following specifications:

• Initial value (CRC_INIT): 0xFFFF
• Polynomial (CRC_POLY): 0x1021
• Width: 16 bits
• Final XOR value: CRC is inverted (~CRC)
• Calculation covers all bytes from Command Code to any custom data

The algorithm works as follows:

1. Initialize CRC to 0xFFFF
2. For each byte in the data:
   • XOR the byte with the CRC
   • For each bit (8 times):
     • If CRC & 0x8000 is set:
       • Shift CRC left by 1 and XOR with 0x1021
     • Else:
       • Shift CRC left by 1
     • Keep only lower 16 bits (AND with 0xFFFF)
3. Invert the final CRC value

Command Reference

Get Reader Information

• Command code: 0xF000
• Request format:
  • Frame length: 0x03
  • Command code: [0xF0, 0x00]
  • CRC: 2 bytes
• Response format:
  • Frame length: Variable
  • Command code: [0xF0, 0x00]
  • Error code: 2 bytes (0x0000 = success)
  • Serial number: 16 bytes
  • Data: Model, version, and additional info
  • CRC: 2 bytes

Sound Buzzer

• Command code: 0xF001
• Request format:
  • Frame length: 0x03
  • Command code: [0xF0, 0x01]
  • CRC: 2 bytes
• Response format:
  • Frame length: 0x05
  • Command code: [0xF0, 0x01]
  • Error code: 2 bytes
  • CRC: 2 bytes

ISO15693 Operations

Inventory (Single Slot)

• Command code: 0x1001
• Request format options:
  1. With AFI:
     • Frame length: 0x05
     • Command code: [0x10, 0x01]
     • Flags: 0x36 (Data rate + AFI)
     • AFI value: 1 byte
     • CRC: 2 bytes
  2. Without AFI:
     • Frame length: 0x04
     • Command code: [0x10, 0x01]
     • Flags: 0x26 (Data rate only)
     • CRC: 2 bytes
• Response format:
  • Frame length: Variable
  • Command code: [0x10, 0x01]
  • Error code: 2 bytes
  • Number of cards: 1 byte
  • Card UIDs: 8 bytes per card
  • CRC: 2 bytes

Read Single Block

• Command code: 0x1006
• Request format:
  • Frame length: 0x06
  • Command code: [0x10, 0x06]
  • Flags: 0x02/0x42 (Data rate, optional high-speed)
  • Block length: 1 byte
  • Block number: 1 byte
  • CRC: 2 bytes
• Response format:
  • Frame length: Variable
  • Command code: [0x10, 0x06]
  • Error code: 2 bytes
  • Response flag: 1 byte
  • Block security status: 1 byte (if option flag set)
  • Block data: Variable length
  • CRC: 2 bytes

Write Single Block

• Command code: 0x1007
• Request format:
  • Frame length: Variable (6 + data length)
  • Command code: [0x10, 0x07]
  • Flags: 0x02/0x42
  • Block length: 1 byte
  • Block number: 1 byte
  • Data: Variable length
  • CRC: 2 bytes
• Response format:
  • Frame length: 0x05
  • Command code: [0x10, 0x07]
  • Error code: 2 bytes
  • CRC: 2 bytes

AFI Operations

Write AFI

• Command code: 0x100A
• Request format:
  • Frame length: 0x05
  • Command code: [0x10, 0x0A]
  • Flags: 0x02/0x42
  • AFI value: 1 byte
  • CRC: 2 bytes
• Response format:
  • Frame length: 0x05
  • Command code: [0x10, 0x0A]
  • Error code: 2 bytes
  • CRC: 2 bytes

ISO14443A Operations

Inventory

• Command code: 0x2F01
• Request format:
  • Frame length: 0x03
  • Command code: [0x2F, 0x01]
  • CRC: 2 bytes
• Response format:
  • Frame length: Variable
  • Command code: [0x2F, 0x01]
  • Error code: 2 bytes
  • UID length: 1 byte (4/7/10)
  • UID: Variable length
  • CRC: 2 bytes

Read Block (Mifare)

• Command code: 0x2102
• Request format:
  • Frame length: 0x04
  • Command code: [0x21, 0x02]
  • Block number: 1 byte
  • CRC: 2 bytes
• Response format:
  • Frame length: 0x14
  • Command code: [0x21, 0x02]
  • Error code: 2 bytes
  • Block data: 16 bytes
  • CRC: 2 bytes

Write Block (Mifare)

• Command code: 0x2103
• Request format:
  • Frame length: 0x14
  • Command code: [0x21, 0x03]
  • Block number: 1 byte
  • Data: 16 bytes
  • CRC: 2 bytes
• Response format:
  • Frame length: 0x05
  • Command code: [0x21, 0x03]
  • Error code: 2 bytes
  • CRC: 2 bytes

Key notes for all commands:

• All multi-byte values are in big-endian format
• Error code 0x0000 indicates success
• Frame length includes all fields except itself
• CRC is calculated over all fields except frame length and CRC itself
• Response data validity should be checked via error code and CRC verification

License

This project is licensed under the MIT License - see the LICENSE file for details.