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The BV4239 is a very small low cost RTC with battery back up based on the DS1307. This device also has about 50 bytes of none volatile memory for general purpose storage. The time is kept in 8 registers 0 to 7 and the device address is 0xd0 (8 bit). also on the same PCB is a 24c32 EEPROM that is organised as 4096 x 8, the address of this is 0xa0 (8 bit). Both are accessed via the I2C bus.

Data Sheet There is no data sheet for the PCB as all of the connections are marked on the pcb so its not necessary, there are however data sheets for the two individual devices.

[EEPROM Data sheet for the 24c32 EEPROM
[RTC Data sheet for the DS1307 RTC


The VCC,GND,SDA and SCL pads are on both sides of the PCB, only one of the set need connecting as they are internally connected together. The DS and SQ pins are explained in the appropriate data sheet.


The ByPic software can be found here. This is in the I2C section and there is an example for the RTC and EEPROM.