OG_MU-4-434_v10e Circuit Design, Inc.
6
OPERATION GUIDE
1.3 Example of the Control Method
The VCC terminal of the MU-4 is connected directly to the power source of the mounted CPU. Ensure that the
voltage of the power supply is regulated to within DC +3.0 v to +5.0 v.
Basically the MU-4 uses hardware flow control with RTS or CTS, however 3-line control can be used without the
hardware flow control. In this case, set the CTS terminal to Low level. In addition, care is required with the timing of
transmitting and receiving.
Example 1 and Example 2 are basically the same methods except for the difference in control voltage.
1.3.1 Example 1: Controlling the MU-4 with the on-board CPU
It is possible to interface the MU-4 directly using the UART interface of the on-board CPU.
1.3.2 Example 2: Controlling the MU-4 via RS232C
1. Using the RS232 port of your computer, you can develop a new program for OS’s such as Windows and the like.
In this case, use an RS232C transceiver. (The program for existing system equipment will not work.)
2. By supplying power to the MU-4 with a cable, you can also isolate the radio component from your system and
locate it in the most suitable environment. The distance can be extended by 15 m to 50 m, but the exact distance
should be confirmed through experiments.
* To use the Evaluation Software Program, the DSR signal line should be set to High level.
* When hardware flow control is not used, connect the RTS and CTS at RS232C level.
RXD
TXD
CTS(Port)
RTS(Port)
Port
User CPU
With UART
Peripheral
Antenna
DC +3.0v to +
5.0v
Regulator
+
-
+
3.0v to +
5.0v
DC Power
Tx,
Rx Indicator
MU
-4
TXD 1
RXD 2
RTS 3
CTS 4
MOD 5
INI 6
RST 7
RXM 8
RF
14 GND
13 VCC
12 RXL
11 TXL
10 DO
9 DI
User
RS232 system
1
RXD
2
TXD
3
DTR
4
GND
5
DSR
6
RTS
7
CTS
8
9
1
2
RXD
3
TXD
4
DTR
5
GND
6
DSR
7
RTS
8
CTS
9
D-Sub 9pin
D
-Sub 9
pin
Straight
cable
RS232
transceiver
Regulator
+
-
DC +3.0v to +
5.0v
DC Power
+
3.0v to +
5.0v
MU-4
Antenna
Tx,Rx Indicator
TXD 1
RXD 2
RTS 3
CTS 4
MOD 5
INI 6
RST 7
RXM 8
RF
14 GND
13 VCC
12 RXL
11 TXL
10 DO
9 DI
