H8S-2633 Datasheet, PDF (820/1487 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer

Section 16 Serial Communication Interface (SCI, IrDA) (The H8S/2695 is not equipped with an IrDA function)
16.3.4 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 16.14 shows the general format for clocked synchronous serial communication.
*
Serial
clock
Serial
data
Don’t care
LSB
Bit 0
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 16.14 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.
Rev. 5.00 Mar 28, 2005 page 758 of 1422
REJ09B0234-0500