Waveshare PCF8563 RTC module - real-time clock, I2C, 3.3 V

Product Overview

• Real-time clock for microcontroller boards
• Automatically counts seconds, minutes, hours, days, months, and years
• Communicates via the I2C bus using just two connection pins
• 3.3 V operating voltage, also works with 5 V boards when used with a level shifter
• Integrated backup battery keeps the time during extended power outages
• Small form factor, fits on breadboards and in tight assemblies

Product Description

A real-time clock module maintains the accurate time even when the main board has no power. The PCF8563 communicates via the I2C bus, which connects multiple sensors and modules using two shared data lines, significantly reducing the number of connection cables required. The internal backup battery powers the timekeeping function even when the microcontroller board is switched off. The module then automatically synchronizes with the system values the next time it starts.

The 3.3 V operating voltage enables direct connection to compatible boards such as Raspberry Pi and ESP-32 variants. When working with 5 V boards, a level shifter is required for the I2C lines to protect the module from excessive voltage. Accuracy is typically better than one minute of deviation per month.

These modules are used wherever accurate time is essential without relying on external network access. A data logger must record every measurement with a timestamp, a temperature controller must follow programmed switching times, and a smart home station must operate independently of the internet and router. The module only requires I2C drivers in the programming environment and a small CR2032 backup battery, which must be purchased separately.

Safety Notice

This module is intended exclusively for building prototypes and for testing and development purposes. It must not be installed in the household electrical circuit. When working near household electrical installations, consult a qualified electrician before commissioning the device.

Scope of Delivery

• 1x Waveshare PCF8563 - RTC Module for Arduino