M16C/62 Group DATASHEET

Clock asynchronous serial I/O (UART) modeMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER• Example of transmit timing when transfer data is 8 bits long (parity enabled, one stop bit)TcThe transfer clock stops momentarily as CTS is “H” when the stop bit is checked.The transfer clock starts as the transfer starts immediately CTS changes to “L”.Transfer clockTransmit enablebit(TE)Transmit bufferempty flag(TI)CTSiTxDiTransmit registerempty flag (TXEPT)“1”“0”“1”“0”“H”“L”“1”“0”StartbitData is set in UARTi transmit buffer register.Transferred from UARTi transmit buffer register to UARTi transmit registerParitybitStopbitStopped pulsing because transmit enable bit = “0”ST D0 D1 D2 D3 D4 D5 D6 D7 P SP ST D0 D1 D2 D3 D4 D5 D6 D7 P SP ST D0 D1Transmit interrupt “1”request bit (IR) “0”Shown in ( ) are bit symbols.The above timing applies to the following settings :• Parity is enabled.• One stop bit.• CTS function is selected.• Transmit interrupt cause select bit = “1”.Cleared to “0” when interrupt request is accepted, or cleared by softwareTc = 16 (n + 1) / fi or 16 (n + 1) / fEXTfi : frequency of BRGi count source (f1, f8, f32)fEXT : frequency of BRGi count source (external clock)n : value set to BRGi• Example of transmit timing when transfer data is 9 bits long (parity disabled, two stop bits)TcTransfer clockTransmit enablebit(TE)Transmit bufferempty flag(TI)TxDi“1”“0”“1”“0”Data is set in UARTi transmit buffer registerStartbitSTD0 D1 D2 D3 D4 D5 D6 D7Transferred from UARTi transmit buffer register to UARTi transmit registerStopbitStopbitD8 SP SP ST D0 D1 D2 D3 D4 D5 D6 D7 D8 SPSP ST D0 D1Transmit registerempty flag (TXEPT)“1”“0”Transmit interruptrequest bit (IR)“1”“0”Shown in ( ) are bit symbols.Cleared to “0” when interrupt request is accepted, or cleared by softwareThe above timing applies to the following settings :• Parity is disabled.• Two stop bits.• CTS function is disabled.• Transmit interrupt cause select bit = “0”.Tc = 16 (n + 1) / fi or 16 (n + 1) / fEXTfi : frequency of BRGi count source (f1, f8, f32)fEXT : frequency of BRGi count source (external clock)n : value set to BRGiFigure 1.19.16. Typical transmit timings in UART mode(UART0,UART1)132