Technical information
APPLICATION
2.3 Serial I/O
2-43
3800 GROUP USER’S MANUAL
(4) Communication (transmit/receive) using an asynchronous serial I/O (UART)
Point : 2-byte data is transmitted and received through an asynchronous serial I/O.
The port P4
0 is used for communication control.
Figure 2.3.29 shows a connection diagram, and Figure 2.3.30 shows a timing chart.
Fig. 2.3.29 Connection diagram [Communication using UART]
Specifications : • The Serial I/O is used (UART is selected).
• Transfer bit rate : 9600 bps (f(X
IN) = 4.9152 MHz is divided by 512)
• Communication control using port P4
0
(The output level of the port P40 is controlled by softoware.)
• 2-byte data is transferred from the transmitting side to the receiving side at inter-
vals of 10 ms (generated by timer).
Fig. 2.3.30 Timing chart [Communication using UART]
Transmitting side
P40
3800 group
P40
3800 group
Receiving side
TXD XD
P4
0
T
X
D
10 ms
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
SP(2)
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
ST
SP(2)
D
0
ST
R