Features: 1. The PCF8563 RTC Board provides the real-time clock/calendar function, which can be driven by a battery on board and works independently even when the MCU is turned off. 2. Low-cost, extremely accurate I2C real-time clock (RTC). 3. More steady and precise than DS1302 or DS1307 4. Support I2C bus cascade (by pin, row seat docking method, which can use multiple I2C module) 5. All the possible elicitations: In addition to the necessary interfaces for SDA and SCL, the INT and COT that may be used are also elicited. 6. Spare battery: When the system is powered off, the backup battery supplies power to the PCF8563 chip. The low power consumption of the PCF8563 ensures that the battery can be powered normally for ten years. 7. Crystal oscillator: The new original crystal oscillator ensures the stable and accurate travel time of the chip PCF8563. Specification: Condition: 100% Brand New Item Type: Real Time Clock Module Wide Voltage Range: 1.0-5.5V Typical Value: 0.25uA Output Frequency: 32.768KHz, 1024Hz, 32Hz, 1Hz Battery: CR1220 3V Button Battery Board Size: Approx. 4.2 * 1.7cm / 1.7 * 0.7in Package List: 1 * Real Time Clock Module 1 * Pin Header 1 * Button Battery Notes: 1. The yellow pin shall be attached to the customer during delivery, but not welded to the board; The customer can weld pin or not weld or weld other connectors according to his own needs. 2. The attached program is tested and passed on STC89C52. KEIL compilation environment only provides reference and theoretical technical support, but does not provide debugging and reading service.