Real Time Clock (RTC) Unit (HYM8563)

by M5Stack

UNIT RTC is a programmable real-time clock module

The integrated HYM8563 low-power CMOS real-time clock/calendar chip, using I2C communication interface, full-coverage case can effectively protect the circuit, making its operation more stable. Applicable to a variety of embedded devices, instruments and instruments as a system clock.

Role of RTC

Most MCUs are built-in timers, which usually start working automatically when the hardware is powered on, and reset when the hardware is powered off. The built-in timer can handle some simple timing tasks, but if we want to implement data timestamp recording, clock, alarm clock and other time-span functions, a system power-independent clock RTC is the best choice.


  • Support second/minute/hour/day/month/year. time data reading and writing
  • 32.768kHz high-precision clock crystal, greatly reducing the time error
  • Low power consumption, coin battery can work continuously for years
  • With century mark
  • I2C communication interface


  • 1x Unit RTC
  • 1x Coin cell battery (38mAh)
  • 1x HY2.0-4P cable


Specifications Parameters
Clock chip HYM8563
Crystal Frequency 32.768kHz
Communication interface I2C, addr: 0x51, bus max speed 400Kbps
Power supply voltage 5V DC
Net weight 4.1g
Gross Weight 8.3g
Product Dimensions 48 x 24 x 8mm
Package Size 67 x 53 x 12mm