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RTC (PCF8523)

RTC (PCF8523)

SKU:AX22-0051

Keep accurate time even when your project powers down with this battery-backed RTC module. Built around the PCF8523, it maintains date and time with a coin cell backup so you never lose track of when events happen. Perfect for data logging, scheduling tasks, timestamping sensor readings, or any project that needs to know the current time. The module includes STEMMA QT connectors for easy I²C daisy-chaining and generates an interrupt signal for alarm functions or periodic timing events. The onboard crystal provides accurate timekeeping, while the battery ensures your clock keeps running through power cycles. Drop it into any AX22 backplane and access reliable timekeeping with Arduino IDE, MicroPython, or MicroBlocks.
$7.49
$7.49
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Technical details

  • 22 mm × 22 mm square
  • 4× ⌀2.7 mm Mounting Holes
  • Battery backup slot (CR1216 3V coin cell, bottom layer)
  • I²C interface
  • 2× STEMMA QT
  • 3.3 V, 5.0 V
  • Arduino IDE Compatible
  • MicroPython Compatible
  • MicroBlocks Compatible
Component datasheet

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Pinout & connections

Pinout & connections

Technical Resources

RTC (PCF8523) - (AX22-0051)
Circuit Schematic 3D Model
PCB FRONT
RTC (PCF8523) — PCB FRONT
PCB BACK
RTC (PCF8523) — PCB BACK

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Arduino example

ax22-0051.ino 
#include "RTClib.h"

RTC_PCF8523 rtc;

void setup() {
  Serial.begin(115200);

  if (!rtc.begin()) {
    Serial.println("RTC not found");
    while (1) delay(10);
  }

  if (!rtc.initialized() || rtc.lostPower()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  rtc.start();
}

void loop() {
  DateTime now = rtc.now();

  Serial.printf("%04d/%02d/%02d %02d:%02d:%02d\n",
                now.year(), now.month(), now.day(),
                now.hour(), now.minute(), now.second());

  delay(1000);
}