The MAX2112 has a 7-bit slave address that must be sent to the device following a START condition to initiate communication. The slave address is internally programmed to 1100 000 The write/read address is C0/C1 if ADDR pin is connected to ground. The write/read address is C2/C3 if ADDR pin is connected to VCC.​ The first 6 bits of the address are fixed (1100 00) while the seventh bit can be 0 or 1 depending upon if ADD is connected to GND or Vcc as follows ADD pin is connected to GND The 7 bit slave address will be 1100 000 so a RD address will be 1100 0000 = 0xC0 similarly a WT address will be 1100 0001 = 0 xC1 ADD pin is connected to Vcc The 7 bit slave address will be 1100 001 ​so a RD address will be 1100 0010 = 0xC2 similarly a WT address will be 1100 0011 = 0xC3