RV-3028 real-time clock breakout with ESP32

Supply 3.3 V Bus I2C I2C address 0x52 Measures time

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
GND	Ground	GND
3V3	Power	3V3
SDA	I2C data (SDA)	D21
SCL	I2C clock (SCL)	D22
INT	Interrupt	D35	Alarm / timer interrupt, optional
CLK	Not wired to the ESP32	—	Clock output, not needed
EVI	Not wired to the ESP32	—	Event input (timestamp), optional

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x52);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "RV-3028 real-time clock breakout found at 0x52" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Micro Crystal RV-3028-C7 application manual, I2C address 1010010 (0x52); supply 1.1 to 5.5 V; 45 nA timekeeping
SparkFun Real Time Clock Module RV-3028 (Qwiic) hookup guide, Pins GND, 3.3V, SDA, SCL, INT, CLK, EVI. Check the silkscreen

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.

RV-3028 real-time clock breakout with ESP32

Pins and ESP32 wiring

Starter code (Arduino)

Sources

Try it in 3D in BoardPilot

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