HD64F2638F20J Datasheet, PDF (544/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 13 Serial Communication Interface (SCI)
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
13.3.4 Operation in Clocked Synchronous Mode
In clocked 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 13-14 shows the general format for clocked synchronous serial communication.
*
Serial
clock
Serial
data
LSB
Bit 0
Don’t care
One unit of transfer data (character or frame)
Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6
*
MSB
Bit 7
Don’t care
Note: * High except in continuous transfer
Figure 13-14 Data Format in Synchronous Communication
In clocked synchronous serial communication, data on the transmission 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 clocked serial communication, one character consists of data output starting with the LSB and
ending with the MSB. After the MSB is output, the transmission line holds the MSB state.
In clocked synchronous mode, the SCI receives data in synchronization with the rising edge of the
serial clock.
Page 494 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010