The DS3231 is a low-cost, high-precision I2C real-time clock (RTC) with integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device includes a battery input to maintain timing when main power is removed. Integrated crystals improve accuracy and reduce component count in production. The DS3231 is available in commercial and industrial temperature ranges and comes in a 16-pin, 300-mil SO package. It stores seconds, minutes, hours, day of the week, date, month, and year. Months with fewer than 31 days are automatically adjusted, including leap year corrections. The clock operates in either 24-hour or 12-hour format with AM/PM indication. It features two programmable calendar alarms and a programmable square wave output. Address and data are transmitted serially via the I2C bidirectional bus. A temperature-compensated voltage reference and comparator monitor VCC status, detect power supply failures, provide a reset output, and automatically switch to backup power when necessary. The RST pin can be used as a manual input to generate a microprocessor reset. In addition to high timing accuracy, the DS3231 integrates a digital temperature sensor accessible via the I2C interface (in addition to time data). The temperature sensor accuracy is ±3°C. On-chip control circuitry enables automatic power supply detection and manages switching between primary and backup power (e.g., low-voltage battery). If main power is lost, the device continues to provide accurate timing and temperature readings. An on-chip reset function restarts the system microprocessor when main power is restored or voltage returns to the acceptable range. 1. Other I2C devices can be cascaded. The AT24C32 address can be modified by connecting A0/A1/A2. Default address is 0x57. 2. Required battery model: CR2032, ensuring the clock continues operation after system power-off. 3. Operating voltage: 3.3–5.5 V. 4. Clock chip: High-precision DS3231 RTC. 5. Clock accuracy: ±2 ppm within 0°C to +40°C, resulting in approximately 1 minute annual error. 6. Calendar alarm function included. 7. Programmable square wave output. 8. Real-time clock provides seconds, minutes, hours, day of the week, date, month, and year, with leap-year compensation valid until 2100. 9. Integrated temperature sensor with ±3°C accuracy. 10. Memory chip: AT24C32 (32 Kbit storage capacity). 11. I2C bus interface, supports up to 400 kHz transmission speed (at 5 V operating voltage). Wiring instructions (example for Arduino Uno): SCL → A5 SDA → A4 VCC → 5 V GND → GND Note: Product appearance, color, and printed markings may vary slightly between batches without affecting functionality. Color: As shown. Material: PCB. Package contents: 1 × DS3231 module Other products are not included. Note: Lighting conditions and display settings may cause slight color variation between images and the actual item. Measurement tolerance: ±1–3 cm.