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CHAPTER 20 LIN-UART
■ Inter-CPU Connection Method
External Clock One-to-one connection (normal mode) and master-slave connection (multiprocessor mode)
can be selected. For either connection method, the data length, whether to enable parity, and the
synchronization method must be common to all CPUs. Select an operation mode as follows:
• In the one-to-one connection method, operation mode 0 or 2 must be used in the two CPUs. Select
operation mode 0 for asynchronous transfer mode and operation mode 2 for synchronous transfer mode.
Note, that one CPU has to set to the master and the other to the slave in synchronous mode 2.
• Select operation mode 1 for the master-slave connection method and use it either for the master or slave
system.
■ Synchronization Methods
In asynchronous operation, LIN-UART reception clock is automatically synchronized to the falling edge of
a received start bit.
In synchronous mode, the synchronization is performed either by the clock signal of the master device or
by LIN-UART itself if operating as master.
■ Signal Mode
LIN-UART can treat data only in non-return to zero (NRZ) format.
■ Operation Enable Bit
LIN-UART controls both transmission and reception using the operation enable bit for transmission (SCR:
TXE) and reception (SCR: RXE).
• If reception operation is disabled during reception (data is input to the reception shift register), finish
frame reception and read the received data of the reception data register (RDR). Then stop the reception
operation.
• If the transmission operation is disabled during transmission (data is output from the transmission shift
register), wait until there is no data in the transmission data register (TDR) before stopping the
transmission operation.