Overview：

With compact design, the board can integrate the real-time clock module DS1307, EEPROM memory AT24C32 and digital temperature sensor DS18B20 (not supplied on the board) which are connected via I2C bus together on a 27mm*28mm*8.4mm board.

DS1307 is a low-power real-time clock chip with 56 bytes of non-volatile RAM, full BCD code clock and calendar. The address and data will be transmitted via a two-wire bidirectional serial bus, and the chip can provide information such as seconds, minutes, hours, etc., and the number of days in each month can be automatically adjusted. Besides, there is a compensation function for leap year. AM / PM flag is to determine whether the clock operates in 24-hour or 12-hour mode, and there is a built-in power-sense circuit in the chip with powering down detecting and battery switching functions.

AT24Cxx series of EEPROM are produced by Microchip, a U.S. company. Among which, those of 1-512K-bit support serial CMOS E2PROM with I2C bus data transfer protocol, which are electrically erasable, programmable for self-timed writing cycle (including auto erase time of no more than 10ms, typical time of 5ms) . AT24C32, memory bit of which is 32K bit, can store 8K (8192) bytes. It supports 1.8V to 5V power supply, which can be erased for one million times, and the data can be kept for 100 years. When using a 5V power supply, the clock can reach 400 KHz.