Has anyone simulated a Character LCD?

[reid21]

I would like to capture the signals (d0-7, RS, R/W, E) that drive a character LCD using a daq and then simulate the dislay in LabView, anyone done this?  This is for a test fixture.

[Wiebe@CARYA]

Easiest is to install (drop in the windows\font directory) an LCD font. That
way, you can simply draw your characters in a string control.

See http://www.spinwardstars.com/scrfonts/lcd.html

Regards,

Wiebe.

[reid21]

Thanks but I am not talking about a graphics display, I don't care what font is used.  I have a PCB which drives among other things a LCD module.  I want to test this PCB in a test fixture by connecting up to a DAQ instead of the LCD module.  I want to use the electronic signals that drive the LCD Module and display what the LCD would display on the screen using Labview.  I am about 50% done writing it now.  I will post it when I am done.  Being the hack that I am I am sure that there is a better way but whatever works.

Thanks 

[Troy]

reid, One idea quickly pops to mind that may or may not work.  Have you considered a 2-d array of the round LED indicators?  Make them small, loose the lables, and make a sub VI to load the array based on the data you capture.  Not the fastest thing in the world but might achieve the desired effect.  I am not sure what you need for resolution of the display.  

[RavensFan]

I don't think is problem is how things appear on his front panel.  (Though a display that graphically looks like a real LCD screen might be desirable).  I think his problem is how to capture the various digital lines in hardware, and decode them to what they mean.  Essentially decoding the protocol of those digital lines.

I can't help with this as I don't know the communication protocol and have never worked with LCD panels before.  I don't know how the other control lines affect the display.  I imagine if you are able to capture all 8 digital lines at once (I guess they behave like a parallel interface), the reading of the digital lines could occur as a port and be converted to a numeric value  (does the LCD behave like an ASCII protocol?)  Perhaps the other control lines could go into other digital ports and be treated as triggers for when to capture.

If you are already 50% done, it sounds like you are making pretty good progress.  I wish you luck on the completion of your program.

Message Edited by Ravens Fan on 10-24-2007 10:15 PM

[reid21]

Yes you are correct.  There are actualy 11 lines to decode.  I will just keep hacking away till it works.  I will post it when I am done and I am sure someone can tell me how to do it better.

Thanks, Reid

[Wayne.C]

Reid,

Do you have a part # for the display you are trying to simulate? 

[lmtis]

reid,

do you have the code that you drive the display with (in LV 8 or earlier)?

[reid21]

Just a generic 20x2 character display using a Hitatchi 44780 or equivalant chipset.  I attached a data sheet.

[reid21]

The display is driven by a circuit board.