Adafruit
Adafruit PiRTC - PCF8523 Real Time Clock for Raspberry Pi
The Adafruit PiRTC is a battery-backed real-time clock that plugs directly onto your Raspberry Pi's GPIO header, letting your Pi keep accurate time even when...
The Adafruit PiRTC is a battery-backed real-time clock that plugs directly onto your Raspberry Pi's GPIO header, letting your Pi keep accurate time even when powered off. Built around the PCF8523 RTC with native Linux kernel support, it's ideal for data logging, time-stamping, alarms, and any project that needs reliable timekeeping.
The board comes fully assembled and tested — no soldering required. Just plug it in, pop in a CR1220 coin cell, and configure the RTC using the included tutorial. With a coin cell installed, it will keep time for 5 years or more.
Key Features
- PCF8523 Real-Time Clock – I2C interface with native Raspberry Pi kernel driver support
- Plug-and-Play – Fully assembled; plugs directly onto the Pi GPIO header with no soldering
- Battery Backup – CR1220 coin cell slot keeps time through power loss for 5+ years
- Broad Compatibility – Works with any Raspberry Pi with a GPIO header (Pi 1, 2, 3, 4, 5, Zero, A+, B+)
Ideal For
- Data logging with accurate timestamps
- Clock and alarm projects
- Offline Raspberry Pi setups without network time (NTP)
- Scheduled tasks and timed automation
Package Contents
- 1× Adafruit PiRTC PCF8523 (fully assembled)
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- GPIO
- General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- RTC
- A Real-Time Clock keeps track of time even when the main processor is asleep or powered down, usually with a small backup battery. It matters for data logging and tracking projects that need accurate timestamps.
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Raspberry Pi
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