The I2C slave address of the DS3902 depends on the state of the ADD_SEL pin. If this pin is low, then the slave address is A2h and can‘t be changed through software. If the ADD_SEL pin is high, then
the slave address is determined by the value stored in EEPROM at address 00h. Refer to the Memory Map to see the factory default of the slave address. The seven most significant bits are used (the LSB is not used because it is in the bit position of the R/W bit) to allow the slave address to be programmed to one of 128 possible addresses.