| Feature | Details |
| RTC Chip | Maxim DS3231SN |
| Accuracy | ±2ppm (approx. 1 minute per year) |
| EEPROM | AT24C32 (32K bits / 4KB storage) |
| Interface | I2C (Serial Data and Clock) |
| Operating Voltage | 3.3V to 5.5V DC |
| Battery Type | CR2032 (Not included) |
Product Description The DS3231 RTC Module is a low-cost, extremely accurate I2C real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. Unlike cheaper RTCs like the DS1307, the DS3231 maintains highly accurate timekeeping even when the ambient temperature fluctuates, preventing the "time drift" common in standard clocks. It also includes an AT24C32 EEPROM, providing 4KB of non-volatile memory to store alarm settings or small amounts of data. At Robogears, we recommend this module for data loggers, school bell systems, and automated timers where precision is non-negotiable.
Key Highlights
Temperature Compensation: The internal sensor adjusts the frequency of the crystal to compensate for temperature changes, ensuring the clock stays accurate across a wide range of environments.
Dual Programmable Alarms: Features two time-of-day alarms that can trigger an interrupt signal on the SQW pin to "wake up" a sleeping microcontroller.
Battery Backup Support: When the main power is lost, the module automatically switches to a coin cell battery (CR2032) to maintain time for years without external power.
Integrated EEPROM: The onboard AT24C32 chip allows you to save user-defined parameters or log timestamps without needing an external SD card module.
Leap Year & Calendar Support: Automatically handles seconds, minutes, hours, day, date, month, and year information with leap-year compensation valid up to the year 2100.
Technical Specifications
Temperature Sensor Accuracy: ±3°C
I2C Speed: Standard 100kHz and Fast 400kHz modes
Clock Output: 1Hz and 32.768kHz programmable square wave
Dimensions: 38mm x 22mm x 14mm
I2C Addresses: 0x68 (RTC) and 0x57 (EEPROM)
Installation Tip from Robogears: This module is designed for CR2032 (non-rechargeable) batteries. However, some versions of this board have a simple "charging circuit" meant for LIR2032 (rechargeable) batteries. If you are using a standard CR2032, it is highly recommended to disable this circuit by removing the diode or resistor near the battery holder to prevent the coin cell from overheating. For software, use the "RTClib" by Adafruit or the "DS3232RTC" library for advanced features like alarm interrupts.
Note: This product is the DS3231 Module ONLY. The CR2032 battery is not included. Product images are for illustration purposes only.