Adafruit ST25DV16K I2C RFID EEPROM Breakout - STEMMA QT / Qwiic

This RFID tag is unique: it works with mobile phones just like other RFID tags, but you can reprogram it over I2C. The tag shows up as an ISO/IEC 15693 (13.56MHz) chip, readable by phones and tablets, allowing dynamic rewriting when connected to a controller. For example, different URLs can be written and detected by mobile phones sequentially.

Note that popular hobby RFID reader/writer chips such as the PN532 do not support ISO15693, so they cannot read the ST25DV tag once programmed. Both Apple and Android phones successfully read the tags.

The breakout features the ST25DV04 chip, support circuitry, a PCB trace antenna, and 0.100”/2.54mm pitch headers for breadboard use. It also includes Stemma QT connectors compatible with SparkFun Qwiic, allowing easy plug-and-play connectivity. (STEMMA QT cable not included.)

Features

• Two-wire I2C serial interface supporting 1MHz protocol
• Multiple I2C addresses: 0x2D, 0x53 (user memory), 0x57 (system memory)
• Single supply voltage: 1.8V to 5.5V
• Multiple byte write programming (up to 256 bytes)
• Based on ISO/IEC 15693 standard
• NFC Forum Type 5 tag certified
• Supports all ISO/IEC 15693 modulations, coding, sub-carrier modes, and data rates
• Custom fast read access up to 53 Kbit/s
• 16-kbits EEPROM memory with 40-year data retention and high write cycle endurance
• Fast data transfer between I2C and RF interfaces with half-duplex 256-byte buffer
• Analog output pin for energy harvesting to power external components
• User and system memory protected by configurable passwords
• Compact breakout size: 31.7mm x 25.3mm x 4.6mm

As of November 1, 2023, the PCB was updated with Adafruit Pinguin for a more legible silkscreen. Both new and older versions are identical except for silkscreen style.