The RTC unit is a programmable real-time clock module, with integrated HYM8563 low-power CMOS real-time clock/calendar chip, using a I2C communication interface, a full-coverage case can effectively protect the circuit making its operation more stable. Lithium Battery Shipping: Due to courier restrictions, this product can only be shipped within the United Kingdom. With this item in your cart, your shipping options will be limited and may cost more than our usual rates. Why? Features * 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 Package Contents * 1x Unit RTC * 1x Coin cell battery (38mAh) * 1x HY2.0-4P cable Specifications 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 Resources * Documents https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2023-03-07 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2023-12-27 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2024-09-19 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2024-11-29 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2024-11-30 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2025-04-29 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2025-11-28 https://elecena.pl/product/22723531/m5stack-real-time-clock-rtc-unit-hym8563 2025-11-29