Technical information

2-31

3800 GROUP USER’S MANUAL

APPLICATION

2.3 Serial I/O

2.3.5 Serial I/O application examples

(1) Communication using a clock synchronous serial I/O (transmit/receive)

Outline : 2-byte data is transmitted and received through the clock synchronous serial I/O. The SRDY

signal is used for communication control.

Figure 2.3.13 shows a connection diagram, and Figure 2.3.14 shows a timing chart.

Fig. 2.3.13 Connection diagram [Communication using a clock synchronous serial I/O]

Specifications : • The Serial I/O is used (clock synchronous serial I/O is selected)

• Synchronous clock frequency : 125 kHz (f(X

IN) = 4 MHz is divided by 32)

• The SRDY (receivable signal) is used.

• The receiving side outputs the SRDY signal at intervals of 2 ms (generated by

timer), and 2-byte data is transferred from the transmitting side to the receiving

side.

P42/INT0

SCLK1

TXD

3800 group

SRDY

SCLK

RXD

3800 group

Transmitting side Receiving side

Fig. 2.3.14 Timing chart [Communication using a clock synchronous serial I/O]

• • • •

D0 D4D2D1 D6D5 D7D3 D0 D4D2D1 D6D5 D7D3 D0 D1

• • • •

TXD

CLK

SRDY

2 ms