HD64F2149YV datasheet(482/1075 Pages) RENESAS

482 / 1075 page

Section 15 Serial Communication Interface (SCI, IrDA)

Rev. 3.00 Jan 18, 2006 page 454 of 1044

REJ09B0280-0300

15.3

Operation

15.3.1

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 15.8. 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 15.9.

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

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