M38002M4 Datasheet, PDF (79/173 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

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.
Transmitting side
Receiving side
P42/INT0
SCLK1
TXD
3800 group
SRDY
SCLK
RXD
3800 group
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(XIN) = 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.
SRDY
SCLK
TXD
D0 D1 D2 D3 D4 D5 D6 D7
D0 D1 D2 D3 D4 D5 D6 D7
2 ms
••••
••••
D0 D1 • • • •
Fig. 2.3.14 Timing chart [Communication using a clock synchronous serial I/O]
3800 GROUP USER’S MANUAL
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