Writing "Hello World" to a USB to serial converter
From Rxtx
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This example shows how write a Java program to write out "Hello World" to a USB to serial converter connected to a Windows XP computer. | This example shows how write a Java program to write out "Hello World" to a USB to serial converter connected to a Windows XP computer. | ||
| - | Firstly the USB to serial converter in installed using the manufacturer's instructions. Select My Computer->Properties->Hardware->Device Manager->Ports(COM&LPT)->USB - Serial Comm Port (COM4). This shows | + | Firstly the USB to serial converter in installed using the manufacturer's instructions. Select My Computer->Properties->Hardware->Device Manager->Ports(COM&LPT)->USB - Serial Comm Port (COM4). This shows a COM port to which the device was installed - in this case COM4. |
Then install Sun's Java software (JDK6 Update 3). The JDK files are placed at C:\Program Files\Java\jdk1.6.0_03\ and the runtime files are placed at C:\Program Files\Java\jre1.6.0_03\. Ensure the System Variable "path" (held in My Computer->properties->Advanced->Environment Varables->System Variables) includes ";C:\Program Files\Java\jdk1.6.0_03\bin" at the end. | Then install Sun's Java software (JDK6 Update 3). The JDK files are placed at C:\Program Files\Java\jdk1.6.0_03\ and the runtime files are placed at C:\Program Files\Java\jre1.6.0_03\. Ensure the System Variable "path" (held in My Computer->properties->Advanced->Environment Varables->System Variables) includes ";C:\Program Files\Java\jdk1.6.0_03\bin" at the end. | ||
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Copy the SimpleWrite java program from here: [http://java.sun.com/developer/releases/javacomm/SimpleWrite.java]. Edit the file as follows: | Copy the SimpleWrite java program from here: [http://java.sun.com/developer/releases/javacomm/SimpleWrite.java]. Edit the file as follows: | ||
| - | Change the third import statement "import javax.comm.*;" to read "import gnu.io.*;" | + | *Change the third import statement "import javax.comm.*;" to read "import gnu.io.*;" |
| - | + | *Change the line "String defaultPort = "/dev/term/a";" to read "String defaultPort = "COM4";" (or to whichever port the USB to serial converter is installed) | |
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| - | Change the line "String defaultPort = "/dev/term/a";" to read "String defaultPort = "COM4" | + | |
This Java program can be compiled and run by typing the following at the Command Prompt: | This Java program can be compiled and run by typing the following at the Command Prompt: | ||
Revision as of 20:15, 29 October 2007
This example shows how write a Java program to write out "Hello World" to a USB to serial converter connected to a Windows XP computer.
Firstly the USB to serial converter in installed using the manufacturer's instructions. Select My Computer->Properties->Hardware->Device Manager->Ports(COM&LPT)->USB - Serial Comm Port (COM4). This shows a COM port to which the device was installed - in this case COM4.
Then install Sun's Java software (JDK6 Update 3). The JDK files are placed at C:\Program Files\Java\jdk1.6.0_03\ and the runtime files are placed at C:\Program Files\Java\jre1.6.0_03\. Ensure the System Variable "path" (held in My Computer->properties->Advanced->Environment Varables->System Variables) includes ";C:\Program Files\Java\jdk1.6.0_03\bin" at the end.
Install RxTx. This involves placing rxtxSerial.dll and rxtxParallell.dll in both C:\Program Files\Java\jdk1.6.0_03\jre\bin and C:\Program Files\Java\jre1.6.0_03\bin. It also involves placing RXTXcomm.jar in both C:\Program Files\Java\jdk1.6.0_03\jre\lib\ext and C:\Program Files\Java\jre1.6.0_03\lib\ext.
Copy the SimpleWrite java program from here: [1]. Edit the file as follows:
- Change the third import statement "import javax.comm.*;" to read "import gnu.io.*;"
- Change the line "String defaultPort = "/dev/term/a";" to read "String defaultPort = "COM4";" (or to whichever port the USB to serial converter is installed)
This Java program can be compiled and run by typing the following at the Command Prompt:
javac SimpleWrite.java java SimpleWrite
"Hello World" should then appear on the device connected to the serial port, assuming that it has been set up to receive a 9600 baud rate, 8 data bits, 1 stop bit, no parity and no handshaking.
