This module has a DALLAS DS1307 chip for Real Time Clock (RTC) and ATMEL 24C32 EEPROM (4Kbytes) This module is compatible with any micro-controller-based system via the I²C bus.
It works with a rechargeable lithium battery LIR2032 with a charging circuit But it is possible to use a 3V CR2032 Lithium battery, making a modification: Remove resistors R4 / R5 / R6 and diode D1 Replace the resistance R6 with a strap Replace the LIR2032 battery with a CR2032 battery.
The address of the EEPROM memory can not be modified because there are no coding jumpers Pins A0, A1, A2 are connected to 0v. The binary address is therefore fixed at 1010000X (ie $ A0 in hexadecimal), where X is the R / W bit. The location of the resistance R7 (polarization of quartz in pin 2) is empty, it is normal and the module works perfectly like this The slot for U1 is empty, it can accommodate a temperature sensor (not delivered) "One-Wire" as a DALLAS DS1820 or DS18B20, etc ...
Fully charged, the battery can power the DS1307 to provide time (date and time) for 1 year. The module can obviously be cascaded with other I²C devices, provided that we respect the addresses of each (no duplicate addresses ...).