RC522 RFID with ESP32-S3-DevKitC-1

Wiring for the RC522 RFID reader (13.56 MHz) on the ESP32-S3-DevKitC-1 (ESP32-S3, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

RC522 RFID pin	Role	ESP32-S3-DevKitC-1 pin	Notes
SDA	SPI chip select	10	This is the SPI chip select (CS), despite the SDA label
SCK	SPI clock	12
MOSI	SPI MOSI	11
MISO	SPI MISO	13
IRQ	Interrupt	39	Interrupt, optional. Leave unconnected
GND	Ground	G
RST	Input to the part	4	Reset, active LOW
3.3V	Power	3V3	3.3 V only. Never 5 V

Check before you power it on

Supply: 3.3 V from the 3V3 pin.

Test code (Arduino)

// Library: MFRC522 (miguelbalboa)
#include <SPI.h>
#include <MFRC522.h>

MFRC522 rfid(10, 4);  // SDA is the SPI chip select

void setup() {
  Serial.begin(115200);
  SPI.begin();
  rfid.PCD_Init();
  rfid.PCD_DumpVersionToSerial();  // 0x91 or 0x92 means the reader answers
}

void loop() {
  if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial()) return;
  for (byte i = 0; i < rfid.uid.size; i++) Serial.print(rfid.uid.uidByte[i], HEX);
  Serial.println();
  rfid.PICC_HaltA();
}

Arduino board: esp32:esp32:esp32s3. Use the port labelled UART. If uploading does not start, hold BOOT, press and release RESET, then release BOOT.

Questions

Which ESP32-S3-DevKitC-1 pins do I use for the RC522 RFID?

SDA → 10, SCK → 12, MOSI → 11, MISO → 13, IRQ → 39, GND → G, RST → 4, 3.3V → 3V3.

Does the RC522 RFID work with the ESP32-S3-DevKitC-1 at 3.3 V?

Yes: the RC522 RFID runs at 3.3 V and the ESP32-S3-DevKitC-1 uses 3.3 V signals, so no level shifting is needed.

BoardPilot checks this wiring in 3D as you build it, and finds crossed or missing wires on the real board.

Download BoardPilot

Full ESP32-S3-DevKitC-1 pinout · RC522 RFID reader (13.56 MHz): all pins and data

The RC522 RFID on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico Teensy 4.1

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