Operation In Synchronous Mode - Renesas H8S/2319 series Hardware Manual

12.3.4

Operation in Synchronous Mode

In synchronous mode, data is transmitted or received in synchronization with clock pulses, making
it suitable for high-speed serial communication.
Inside the SCI, the transmitter and receiver are independent units, enabling full-duplex
communication by use of a common clock. Both the transmitter and the receiver also have a
double-buffered structure, so that data can be read or written during transmission or reception,
enabling continuous data transfer.
Figure 12-14 shows the general format for synchronous serial communication.
*
Serial
clock
Serial
data
Don't care
Note: * High except in continuous transfer
Figure 12-14 Data Format in Synchronous Communication
In synchronous serial communication, data on the communication line is output from one falling
edge of the serial clock to the next. Data confirmation is guaranteed at the rising edge of the serial
clock.
In synchronous serial communication, one character consists of data output starting with the LSB
and ending with the MSB. After the MSB is output, the communication line holds the MSB state.
In synchronous mode, the SCI receives data in synchronization with the rising edge of the serial
clock.
Data Transfer Format: A fixed 8-bit data format is used.
No parity or multiprocessor bits are added.
Rev. 5.00, 12/03, page 470 of 1088
One unit of transfer data (character or frame)
LSB
Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5
*
MSB
Bit 6 Bit 7
Don't care