The DS3231 is a low cost, high precision I2C real time clock () with integrated temperature compensated crystal oscillator (TCXO) and crystal. The device includes a battery input that maintains accurate timing when the mains supply is disconnected. The integrated crystal oscillator increases the long-term accuracy of the device and reduces the number of components in the production line. The DS3231 is available in both commercial and industrial temperature ranges and is available in a 16-pin 300 SO package. The saves seconds, minutes, hours, weeks, dates, months, and years. For months less than 31 , the date of the month will be automatically adjusted, including the correction for the . The working format of the clock can be 24 hours or a 12-hour format with /AM/PM indication. Two configurable calendar alarms and a configurable square wave output are available. The address and data are transmitted serially via the I2C bidirectional bus. Working voltage: 3.3--5.5V Clock chip: high precision clock chip DS3231 Clock accuracy: 0-40 C, accuracy 2ppm, annual error of about 1 minute With 2 calendar alarm clocks Programmable square wave output The real-time clock generates seconds, minutes, hours, weeks, dates, months, and years, and provides compensation valid until 2100 The chip has its own temperature sensor with an accuracy of +/- 3C. Memory chip: AT24C32 (storage capacity 32K) 11.IIC bus interface, the maximum transmission speed is 400KHz (when the working voltage is 5V) Other IIC devices can be cascaded. The 24C32 address can be modified by short-circuiting A0/A1/A2. The default address is 0x57. With battery CR2032 (without battery), after the system is powered off, the clock will still move normally. Wiring instructions (take for r3 as an example): SCLA5 SDAA4 VCC5V GNDGND Colour: blue Material: ABS Size: 38x22x14mm Package Contents: 5 * DS3231 AT24C32 clock module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.