Question

I don’t know much about this, so this is going to be a pretty basic question.

I have a nifty little USB thing which emulates a COM port. It’s a simply switch, to which I can send three different signals: ON, OFF and GET STATUS

I’ve tested it using a terminal program called RealTerm. In this, I can open the port at the set baud rate and other options, and then send bin files to the port. When I got the thing, I also downloaded three different .bin files – one for ON, one for BREAK and one for GET STATUS. This works like a charm, and the port returns the corresponding codes etc.

Now, I’d like to try this in Java (first, then possibly C/C++). So I got a library called JSSC (v0.9), which makes this pretty easy. This is what I do:

public static void main(String[] args) {
    String[] portNames = SerialPortList.getPortNames();

    for(int i = 0; i < portNames.length; i++){
        System.out.println(portNames[i]);
    }

    SerialPort serialPort = new SerialPort("COM10");

    try {
        serialPort.openPort();//Open serial port
        serialPort.setParams(SerialPort.BAUDRATE_9600, 
                             SerialPort.DATABITS_8,
                             SerialPort.STOPBITS_1,
                             SerialPort.PARITY_NONE);

        serialPort.writeBytes("0x55 01 01 02 00 00 00 59".getBytes());
        serialPort.closePort();
    }
    catch (SerialPortException ex) {
        System.out.println(ex);
    }
}

The baud rate, data and stop bits are the correct ones. When I plug in the device, the system.out.prinln lists the port, so it looks like the device is detected.

Now, the device has the following code words:

Make:         0x55 01 01 02 00 00 00 59
Break:        0x55 01 01 01 00 00 00 58
Check status: 0x55 01 01 00 00 00 00 57

Should I then just be able to pass those hex strings to the device in the java program, and get/observe the result(s)? If so, how do I do it? Just writeBytes() or writeString() like above doesn’t do anything. (I hear a click from the device when the MAKE or BREAK signal works).

Or is there a way to pass these .bin files to the port, like I do in RealTerm?

Also, does anyone know exactly what kind of files these .bin files might be? The guy I bought it from (cheaply) is not very informative, and doesn’t want to help with things or answer questions not direcly related to the device (which is understandable, of course).

I don’t need to delve into microprocessor programming or similar topics here, since I’m really just trying to accomplish some basic operations. But some insight or overview is of course necessary.

Answer 1

It seems to me, that those codes:

Make:         0x55 01 01 02 00 00 00 59
Break:        0x55 01 01 01 00 00 00 58
Check status: 0x55 01 01 00 00 00 00 57

you have to send like byte-arrays. They look like hex numbers, so try to do this:

byte[] mike = new byte[]{0x55, 0x01, 0x01, 0x02, 0x00, 0x00, 0x00, 0x59};
serialPort.writeBytes(mike);
serialPort.flush(); // is this method available? I think you should invoke it, if it is present
serialPort.closePort();