D12320VF25V Datasheet, PDF (494/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 12 Serial Communication Interface (SCI)
12.3 Operation
12.3.1 Overview
The SCI can carry out serial communication in two modes: asynchronous mode in which
synchronization is achieved character by character, and synchronous mode in which
synchronization is achieved with clock pulses.
Selection of asynchronous or synchronous mode and the transmission format is made using SMR
as shown in table 12.8. The SCI clock is determined by a combination of the C/A bit in SMR and
the CKE1 and CKE0 bits in SCR, as shown in table 12.9.
Asynchronous Mode
• Data length: Choice of 7 or 8 bits
• Choice of parity addition, multiprocessor bit addition, and addition of 1 or 2 stop bits (the
combination of these parameters determines the transfer format and character length)
• Detection of framing, parity, and overrun errors, and breaks, during reception
• Choice of internal or external clock as SCI clock source
⎯ When internal clock is selected:
The SCI operates on the baud rate generator clock and a clock with the same frequency as
the bit rate can be output
⎯ When external clock is selected:
A clock with a frequency of 16 times the bit rate must be input (the built-in baud rate
generator is not used)
Synchronous Mode
• Transfer format: Fixed 8-bit data
• Detection of overrun errors during reception
• Choice of internal or external clock as SCI clock source
⎯ When internal clock is selected:
The SCI operates on the baud rate generator clock and a serial clock is output off-chip
⎯ When external clock is selected:
The built-in baud rate generator is not used, and the SCI operates on the input serial clock
Rev.7.00 Feb. 14, 2007 page 460 of 1108
REJ09B0089-0700