HD64F3048F16 Datasheet, PDF (527/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 13 Serial Communication Interface
13.3.4 Synchronous Operation
In synchronous mode, the SCI transmits and receives data in synchronization with clock pulses.
This mode is suitable for high-speed serial communication.
The SCI transmitter and receiver share the same clock but are otherwise independent, so full
duplex communication is possible. The transmitter and receiver are also double buffered, so
continuous transmitting or receiving is possible by reading or writing data while transmitting or
receiving is in progress.
Figure 13.14 shows the general format in synchronous serial communication.
*
Serial clock
Serial data
One unit (character or frame) of serial data
*
LSB
Bit 0
Bit 1 Bit 2
Bit 3 Bit 4
MSB
Bit 5 Bit 6 Bit 7
Don’t care
Note: * High except in continuous transmitting or receiving
Don’t care
Figure 13.14 Data Format in Synchronous Communication
In synchronous serial communication, each data bit is placed on the communication line from one
falling edge of the serial clock to the next. Data is guaranteed valid at the rise of the serial clock.
In each character, the serial data bits are transmitted in order from LSB (first) to MSB (last). After
output of the MSB, the communication line remains in the state of the MSB. In synchronous mode
the SCI receives data by synchronizing with the rise of the serial clock.
Communication Format
The data length is fixed at 8 bits. No parity bit or multiprocessor bit can be added.
Rev. 3.00 Sep 27, 2006 page 499 of 872
REJ09B0325-0300