The RC522 is a 13.56MHz RFID module that is based on the MFRC522 controller from NXP semiconductors. The module can supports I2C, SPI and UART and normally is shipped with a RFID card and key fob. It is commonly used in attendance systems and other person/object identification applications. #RFID #Module

Production-Ready ESP32 Bulk Dialer PCB with Triple SIM800L, MFRC522 RFID, SPI Storage, and Robust Power Management

Industrial 2-layer ESP32 RFID access controller with 12V input, LM2596 5V rail, 3.3V logic, MFRC522 RFID, I2C LCD, relay output, buzzer, buttons, and debug/test headers.

Datasheet-driven MFRC522 RFID reader PCB intended to replicate RC522 module behavior at 13.56 MHz with a 3.3 V nominal supply, 2.5 V to 3.3 V operating range, and RC522-style 8-pin host header compatibility. The MFRC522 datasheet is the authoritative source for pin usage, power rail relationships, oscillator requirements, reset/IRQ handling, and antenna interface topology. AVDD, DVDD, and TVDD must be tied to the same 3.3 V rail; PVDD must be equal to or lower than DVDD; unused MFIN must be tied to SVDD or PVSS; SVDD must be tied to a valid supply if not used independently. The design must use a 27.12 MHz crystal meeting CL 10 pF and ESR <= 100 ohms, local 100 nF decoupling on each MFRC522 supply grouping plus bulk capacitance, and an RF front-end based on the MFRC522 application diagram and reference reader matching/tuning network. PCB priorities are short crystal and RF connections, compact placement of decoupling capacitors at supply pins, solid ground reference, and protected antenna region with minimal digital routing through the RF area.

MFRC522 module I2C