Chapter 12Serial interface 0 and 1Operation XII - 1112.3 Operation12.3.1 OperationSerial interface 0 and 1 can be used for both clock synchronous and duplex UART serial interfaces.12.3.2 Clock Synchronous Serial Interface■ Activation Factor for CommunicationTable: 12.3.1 shows activation factors for communication. At master communication, the transfer clock is gener-ated by setting data to the serial transmission register SCnTB.Table:12.3.1 Synchronous Serial Interface Activation Factor■ Transmission Data BufferThe transmission data buffer, SCnTB is a buffer of reserve that stores data to load to the internal shift register.Data to be transferred should be set to the transmission data buffer, SCnTB, to be loaded to the internal shift reg-ister automatically.■ Reception Data BufferThe reception data buffer, SCnRB is a buffer of reserve that pushes the received data in the internal shift register.After the communication complete interrupt SCnTIRQ is generated, all data stored in the internal shift register arestored to the reception data buffer SCnRB automatically. SCnRB can store data up to 1 byte. SCnRB is rewrittenin every time when communication is completed, so read out data of SCnRB till the next reception is completed.The reception data flag SCAnRXA is set to “1” after SCnTIRQ is generated. SCAnEXA flag is cleared to “0”after SCnRB is read out...If a start condition is fed and activation restarts during communication, the transmission datais invalid. Set the transmission data to SCnTB again to retransmit data.....SCnRB is rewritten every time when communication is completed. Data of SCnRB should beread out until the next reception is completed for continuous communication...Activation factorTransmission Reception Transmission/ReceptionMaster communication Set transmission data Set dummy data Set transmission dataSlave communication Input clock after transmissiondata is setInput clock Input clock after transmissiondata is set
