M5Stack Unit RFID2 MakeCode Extension

Event-driven MFRC522 (I2C) driver to read card UIDs with namespace m5rfid. Supports both 4-byte (MIFARE Classic) and 7-byte (NTAG) UIDs.

Blocks

Main Blocks

• init RFID: initialize the reader (uses default I2C address 0x28)
• on RFID tag detected: event handler that runs when a tag is detected, receives UID as parameter

Advanced Blocks

• is new RFID card present: checks for a new card in the field
• read RFID UID: reads the UID via anti-collision and select (supports cascade levels for 7-byte UIDs)
• RFID UID (hex): returns the UID as a colon-separated hex string (e.g., "04:A1:B2:C3:D4:E5:F6")
• RFID UID bytes: returns the UID as byte array
• RFID type name: returns a simple card type name based on SAK (supports MIFARE and NTAG types)
• get antenna gain: returns the current receiver gain value (0-7)
• set antenna gain to: sets the receiver gain value (0-7)

Example

Event-driven approach (recommended):

m5rfid.init()

m5rfid.onTagDetected(function (uid) {
    serial.writeLine("UID: " + uid)
    serial.writeLine("Type: " + m5rfid.typeName())
    basic.showString("OK")
})

Manual polling approach:

m5rfid.init()

basic.forever(function () {
    if (m5rfid.isNewCardPresent() && m5rfid.readUid()) {
        const uid = m5rfid.getUidHex()
        const typ = m5rfid.typeName()
        serial.writeLine("PICC type: " + typ)
        serial.writeLine("UID: " + uid)
        basic.showString("OK")
        basic.pause(500)
    }
})

Antenna Gain

The antenna gain can be adjusted to improve reading performance at different distances. Valid values are 0-7:

• 0 = 18dB
• 1 = 23dB
• 2 = 18dB
• 3 = 23dB
• 4 = 33dB (default)
• 5 = 38dB
• 6 = 43dB
• 7 = 48dB (maximum)

Notes

• This driver supports 4-byte UIDs (MIFARE Classic) and 7-byte UIDs (NTAG).
• Implements proper cascade level handling for multi-level UIDs.
• I2C address defaults to 0x28 per M5Stack Unit RFID2.
• No external dependencies - uses only built-in MakeCode APIs.

Credits

This implementation is based on MFRC522_I2C by kkloesener.