Description Unit RTC is a programmable real-time clock module based on the HYM8563 low-power CMOS real-time clock/calendar chip. It uses the I2C communication interface and is designed to provide reliable timekeeping for embedded devices, instruments, clocks, alarms, and power-off time synchronization applications. The module supports reading and writing seconds, minutes, hours, day of the week, day, month, and year. It integrates a 32.768kHz high-precision clock crystal oscillator to reduce time error, and its fully enclosed shell helps protect the circuit for more stable operation. Features HYM8563 RTC chip: integrates the HYM8563 low-power CMOS real-time clock/calendar chip. I2C communication: uses I2C communication at address 0x51. Time and date access: supports reading and writing seconds, minutes, hours, day of the week, day, month, and year. 32.768kHz crystal: high-precision clock crystal oscillator helps reduce time error. Low power consumption: powered by a button battery for long-term timekeeping. Century flag: includes century flag support. Protected enclosure: fully enclosed shell helps protect the circuit and improve operation stability. Specifications Product Unit RTC SKU U126 Clock Chip HYM8563 Crystal Frequency 32.768kHz Communication Interface I2C @ 0x51, maximum bus speed 400Kbps Power Supply DC 5V Product Size 48.0 x 24.0 x 8.0mm Product Weight 7.4g Package Size 138.0 x 93.0 x 9.0mm Gross Weight 12.8g Protocol Protocol Type I2C I2C Address 0x51 Maximum Bus Speed 400Kbps Readable / Writable Data Seconds, minutes, hours, day of the week, day, month, and year Clock Reference 32.768kHz crystal oscillator Applications Clocks and alarms. Power-off time synchronization. Embedded device system clock. Instrument timekeeping. Product List 1 Unit RTC 1 HY2.0-4P Grove Cable (20cm) Other Content Timekeeping function: Unit RTC can keep date and time information for embedded systems. Power-off synchronization: the low-power RTC design helps maintain time information when the main system is powered off. Stable operation: the enclosed shell helps protect the circuit during use. Resources Official Documents HYM8563 Datasheet Unit RTC Example for M5Series Unit RTC Example for M5Atom Unit RTC Example for M5Core Unit RTC Example for M5StickC Unit RTC Official Video FAQ What is Unit RTC used for? It is used as a real-time clock module for clocks, alarms, power-off time synchronization, embedded devices, and instruments. Which RTC chip does it use? It uses the HYM8563 low-power CMOS real-time clock/calendar chip. Which communication interface does it use? It uses I2C communication at address 0x51. What is the maximum I2C bus speed? The official specification lists a maximum bus speed of 400Kbps. What time and date fields can be accessed? It supports reading and writing seconds, minutes, hours, day of the week, day, month, and year. What crystal frequency does it use? It uses a 32.768kHz high-precision clock crystal oscillator. What is included in the package? The package includes 1 Unit RTC and 1 HY2.0-4P Grove Cable (20cm).
