Master transmitter:-[Write_RTC]
 1.  START condition transmitted.
                case SMB_START:    	//0x08
 2.   Slave address + WRITE transmitted.  ACK received.
                 case SMB_MTADDACK:   	//0x18
3.    Data byte transmitted.  ACK received.
                 case SMB_MTDBACK:    	//0x28
4.    Idle state                        //0xF8
Master Receiver:-[Read_RTC]
1.  START condition transmitted.
                case SMB_START:    	//0x08
 2.   Slave address + WRITE transmitted.  ACK received.
                case SMB_MTADDACK:   	//0x18
3.    Data byte transmitted.  ACK received.
                case SMB_MTDBACK:    	//0x28
4.    Repeated START condition transmitted.
          case SMB_RP_START:     	//0x10  
5.    Slave address + READ transmitted.  ACK received.
               case SMB_MRADDACK:    	//0x40
6.     Data byte received.  NACK transmitted.
                case SMB_MRDBNACK:    	//0x58
7.    Idle state                        //0xF8