Renesas SH7145F Benutzerhandbuch

REJ06B0357-0100O/Rev.1.00

March 2004

Page 3 of 17

In this task example the SCI (Serial Communication Interface) is used to perform asynchronous
serial data transmission/reception. Figure 2 shows a block diagram of channel 1 (ch1) of the SCI
module. The functions of the elements shown in figure 2 are described below.

TEI_1

TXI_1

RXI_1

ERI_1

SCI1 clock I/O pin 
(SCK1)

SCI1 transmit data   
output pin 
(TXD1)

SCI1 receive data 
input pin
(RXD1)

SCI0 synchronous serial transfer function block

Baud rate generator

Bit rate register 1

(BRR_1)

Clock

Transmit/receive operation control settings

Transfer rate generator

Serial mode register 1

(SMR_1)

Serial control register 1

(SCR_1)

Serial status register 1

(SSR_1)

Serial direction control register 1

(SDCR_1)

Transmit/receive 

control circuit

Interrupt
requests

Transmit data control

Transmit shift register 1

(TSR_1)

Transmit data register 1

(TDR_1)

Receive data control

Receive shift register 1

(RSR_1)

Receive data register 1

(RDR_1)

External 
clock

P

φ

/128

P

φ

/32

P

φ

/8

P

φ

1

On-chip 
peripheral clock

•

Asynchronous Mode

Serial data communication is performed using synchronization by character unit. This allows
serial communication with a standard dedicated asynchronous communication chip such as a
Universal Asynchronous Receiver/Transmitter (UART) or Asynchronous Communication
Interface Adapter (ACIA). In addition, the asynchronous mode supports serial communication
among multiple processors (multiprocessor communication function).