M5Stack U126 UNIT Real Time Clock (RTC)

m5Stack U126 UNIT Real-Time Clock (RTC) is a programmable real-time clock module, integrated HYM8563 low-power CMOS real-time clock/calendar chip. The device uses an I2C communication interface and has a full-coverage case that can effectively protect the circuit, making its operation more stable. Applicable to a variety of embedded devices, instruments, and instruments as a system clock.

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 m5Stack U126 UNIT RTC can handle some simple timing tasks. If the user wants to implement data timestamp recording, alarm clock, and other time-span functions, a system power-independent clock RTC is a great choice.


  • Supports 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
  • Includes century mark
  • I2C communication interface


  • Clock chip - HYM8563
  • 32.768kHz crystal frequency
  • Communication interface - I2C, address: 0x51, bus max speed 400Kbps
  • 5V DC power supply voltage
  • Net weight (4.1g)
  • Gross weight (8.3g)
  • 48mm x 24mm x 8mm product dimensions
  • 67mm x 53mm x 12mm package size

Kit Contents

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


  • Clock, alarm clock
  • Power downtime synchronization
Published: 2021-10-27 | Updated: 2022-03-11