SH7041A datasheet(539/923 Pages) RENESAS

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14.3

Operation

14.3.1

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 (SMR), as shown in table 14.8. The SCI clock

source is selected by the C/

A bit in the serial mode register (SMR) and the CKE1 and CKE0 bits

in the serial control register (SCR), as shown in table 14.9.

Asynchronous Mode:

• Data length is selectable: seven or eight bits.

• Parity and multiprocessor bits are selectable, as well as the stop bit length (one or two bits).

These selections determine the transmit/receive format and character length.

• In receiving, it is possible to detect framing errors (FER), parity errors (PER), overrun errors

(ORER), and the break state.

• 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

clock, and can output a clock 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 communication format has a fixed 8-bit data length.

• In receiving, it is possible to detect overrun errors (ORER).

• 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

clock, 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.

SH7041A Datasheet(PDF) 539 Page - Renesas Technology Corp