Chapter 12Serial interface 0 and 1Operation XII - 13■ Setting ClockThe SCnCKS1 to 0 of the SIFCLK register selects a clock source from the internal clock (clock master), or theSBTn pins selects it from the external clock (clock slave) by .Table:12.3.3 Synchronous Serial Interface Clock Source■ Setting Data Input/Output Pins3-channel type (clock pin (SBTn pin), data output pin (SBOn pin), and data input pin (SBIn pin) ) is used for com-munication...The transfer rate should be up to 3.0 Mbps. If the transfer rate is over 3.0 Mbps, the transmis-sion data may not be sent correctly...■ Reception Data Flag OperationAfter reception is completed (communication complete interrupt SCnTIRQ), data is automatically stored toSCnRB from the internal shift register and the reception data flag SCAnRXA of the SCnSTR register is set to “1”.The SCAnRXA flag is cleared to “0” by reading data from SCnRB.■ Reception BUSY Flag OperationIf data is set to the SCnTB or a start condition is recognized with setting SCAnREN flag of the SCnCTR registerto “enable”, the reception status flag SCAnRBSY of the SCnSTR register is set to “1”. The SCAnRBSY flag iscleared when the communication complete interrupt SCnTIRQ is generated.■ Transmission BUSY Flag OperationIf data is set to SCnTB or a start condition is recognized with setting the SCAnTEN flag of the SCnCTR registerto “enable”, the reception status flag SCAnTBSY of the SCnSTR register is set to “1”. The SCAnTBSY flag iscleared when the communication complete interrupt SCnTIRQ is generated.■ Overrun Error OperationAfter reception is completed, if the next data has been already received before reading out of the data of the recep-tion data buffer SCnRB, overrun error is generated and the SCAnOE flag of the SCnSTR register is set to “1”.The SCAnOE flag is not cleared till the next communication interrupt SCnTIRQ is generated after loading data ofthe SCnRB. These error flags have no effects on communication operation.■ Continuous CommutationThis serial has no continuous transfer function. Do not set data in the transmission data buffer SCnTB duringcommunication.Clock source Serial interfaces 0 and 1Internal clock1/2 of timer 14 underflow1/16 of timer 14 underflow1/2 of timer 15 underflow1/16 of timer 15 underflow1/2 of timer 16 underflow1/16 of timer 16 underflowExternal clock SBTn pin
