M16C User Manual.pdf

UARTMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER(4) How to deal with an errorWhen receiving data, read an error flag and reception data simultaneously to determine which errorhas occurred. If the data read is erroneous, initialize the error flag and the UARTi receive bufferregister, then receive the data again.To initialize the UARTi receive buffer register1. Set the receive enable bit to “0” (disable reception).2. Set the receive enable bit to “1” again (enable reception).To transmit data again due to an error on the reception side, set the UARTi transmit buffer registeragain, then transmit the data again.To set the UARTi transmit buffer register again1. Set the serial I/O mode select bits to “0002” (invalidate serial I/O).2. Set the serial I/O mode select bits again.3. Set the transmit enable bit to “1” (enable transmission), then set transmission data in the UARTitransmit buffer register.(5) Functions selectionIn operating UART, the following functions can be used:_______ _______(a) CTS/RTS function_______CTS function is a function in which an external IC can start transmission/reception by means of______________inputting an “L” level to the CTS pin. The CTS pin input level is detected when transmission/receptionstarts, so if the level is gone to“ H” while transmission/reception is in progress, transmission/receptionstops at the next data.______________RTS function is a function to inform an external IC that RTS pin output level has changed to “L” when_______reception is ready. RTS regoes to “H” at the falling edge of the transfer clock._______ _______When using clock-asynchronous serial I/O, choose one of four types of CTS/RTS functions._______ ______________ _______• CTS/RTS functions disabledCTS/RTS pin is a programmable I/O port.______________ ______________• CTS function only enabledCTS/RTS pin performs the CTS function._______• RTS function only enabled_______ _______• CTS/RTS separation function_______ ______________CTS/RTS pin performs the RTS function._______P60 pin performs the RTS function, and P64 pin per-______________ _______forms the CTS function. When CTS/RTS separation_______ _______function is selected, CTS/RTS function cannot selectsimultaneously.(b) Sleep modeSleep mode is a mode in which data is transferred to a particular microcomputer among those connectedby use of clock-asynchronous serial I/O devices.(c) Data logic select functionThis function is to reserve data when writing to transmit buffer register or reading from receive bufferregister.(d) TxD, RxD I/O polarity reverse functionThis function receive a polarity of TxD port output level and a polarity of RxD port input level.350