Renesas SH7781 用户手册

21.   Serial Communication Interface with FIFO (SCIF) 

Rev.1.00  Jan. 10, 2008  Page 1085 of 1658 

REJ09B0261-0100 

 

Clocked synchronous mode, in which data is transmitted or received in synchronization with clock 
pulses, is suitable for fast serial communication. 

Since the transmitter and receiver are independent units in the SCIF, full-duplex communication 
can be performed by sharing the clock. Both the transmitter and receiver have a 64-stage FIFO 
buffer structure, so that data can be read or written during transmission or reception, enabling 
continuous data transmission or reception. 

Figure 21.15 shows the general format for clocked synchronous communication.  

One unit of transfer data (character or frame)

*

*

Bit 0

Bit 1

Bit 2

Bit 3

Bit 4

Bit 5

Bit 6

Bit 7

Don't care

Don't care

LSB

MSB

Synchronization 
clock

Serial data

Note: *  High except in continuous transfer

 

In clocked synchronous serial communication, data on the communication line is output from one 
fall of the synchronization clock to the next fall. Data is guaranteed to be accurate at the start of 
the synchronization clock. 

In serial communication, each character is output starting with the LSB and ending with the MSB. 
After the MSB is output, the communication line remains in the state of the last data. 

In clocked synchronous mode, the SCIF receives data in synchronization with the rise of the 
synchronization clock.