SH7706 Datasheet, PDF (438/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

Section 14 Serial Communication Interface (SCI)
14.4 Operation
For serial communication, the SCI has an asynchronous mode in which characters are
synchronized individually, and a clock synchronous mode in which communication is
synchronized with clock pulses. Asynchronous/clock synchronous mode and the transmission
format are selected in SCSMR, as listed in table 14.8. The SCI clock source is selected by the
combination of the C/A bit in SCSMR and the CKE1 and CKE0 bits in SCSCR, as listed in table
14.9.
Asynchronous Mode:
• Data length is selectable: seven or eight bits.
• Parity and multiprocessor bits are selectable. So is the stop bit length (one or two bits). The
combination of the preceding selections constitutes the communication format and character
length.
• In receiving, it is possible to detect framing errors, parity errors, overrun errors and breaks.
• An internal or external clock can be selected as the SCI clock source.
 When an internal clock is selected, the SCI operates on the clock of the on-chip baud rate
generator, and can output a serial clock signal with a frequency matching the bit rate.
 When an external clock is selected, the external clock input must have a frequency 16 times
the bit rate. (The on-chip baud rate generator is not used.)
Clock Synchronous Mode:
• The transmission/reception format has a fixed eight-bit data length.
• In receiving, it is possible to detect overrun errors.
• An internal or external clock can be selected as the SCI clock source.
 When an internal clock is selected, the SCI operates on the clock of the on-chip baud rate
generator, and outputs a synchronous clock signal to external devices.
 When an external clock is selected, the SCI operates on the input synchronous clock. The
on-chip baud rate generator is not used.
Rev. 5.00 May 29, 2006 page 390 of 698
REJ09B0146-0500