Programming a 634 USB LCD 20x4 in windows


New member

I just ordered a 634 USB LCD 20x4 USB kit with the cable of course... and I was wondering, is there any documentation on createing software for this USB device? how does the USB device function. Does it emulate a COM port or just show up as a USB LCD device that has special commands to work with it. are there any API's out there for it or documents on how I could write programs for the USB version in C++, VB.NET, or C# (I need to be able to write programs in Windows 2000/XP environment only, not the older ones) Thank you!
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CF Tech

By default, they will emulate a COM port. This method is by far the easiest to work with and retains compatibility with going to RS-232 if you ever desire.

If you wanted to, there is an alternate driver that will talk do the USB converter directly--but there is not real benefit to that method and it is more difficult.


New member
so basicly just the same method as programming as the standard comm port programming the display... is there any way or tutorials on how to program windows xp to directly talk to the comm ports? I know there are a lot of problems with that in xp because they are protected ports now... but how do the people who write drivers for the lcd do it? any info would be great, thanks!


New member
I have attatched a zip with some source code in it to this message, it's a serial port class I wrote a while ago, it works fine with my 633 USB module, so I can't see any problems with a 634, or any other serial device either!

Feel free to pick it to pieces, or use it as-is, the class should be fairly simple to use. It was written in C++ and works under WinXP fine.

Robert 'Heffo' Heffernan


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