HD6417727BP160CV Datasheet, PDF (567/1098 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/ SH7700 Series

Section 17 Serial Communication Interface (SCI)
17.3 Operation
17.3.1 Overview
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 the serial
mode register (SCSMR), as listed in table 17.9. The SCI clock source is selected by the
combination of the C/A bit in the serial mode register (SCSMR) and the CKE1 and CKE0 bits in
the serial control register (SCSCR), as listed in table 17.10.
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 using 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 using 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.6.00 Mar. 27, 2009 Page 509 of 1036
REJ09B0254-0600