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Interfacing Colour Lcd to Parallel port

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sgboi

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i only tried interfacing Dot Matrix Character Lcd b4.. Anyone knows whether colour lcd can be interface through parallel port? how can i go about doing it?
 

crust

Member
If that is the popular sony display, you can interface it with the parallel port. That display uses 9 bits for each pixel (3 ea, RGB) and a few other lines to strobe the horizontal and vertical refresh. However, unlike many LCDs, there is no built in character generator. You have to do all of that in your own software. I suspect you could probably bit-bang the parallel port to control the display -- though I have never tried it with that display myself.
 

sgboi

New Member
have u tried any display b4, which i can look as example? also i found a colour lcd panel but i could not identify where its from, am i able to interface it the pc as well? actually, i just want to make it changes colour when my pc reaches certain temperature so i think there will be no need for the character generator..


Thanks Again!!! :)
 

crust

Member
I have used the regular monochrome LCDs as well as a couple of VFD displays. Most of the displays I have used to not do graphics, though I have used a Noritake VFD that had its own character generator (which means that you tell it "A" and it knows how to light up the elements to form the letter) as well allowing you to address any individual pixel. When I first looked at the Sony display, it seemed like a TV or image sensor. Basically, you give it signals to indicate the start of frame and start of line, then clock in each pixel individually. This means that to make a change to the display you have to redraw everything. On some LCDs you can just say "change the character at position 4 to an X" (I am oversimplifying).
 

sgboi

New Member
Thanks for the info.. But do i need a character generater if i only want to change the colour of the whole lcd? and also, what is the pinout of a colour lcd panel(no driver and controller)? i mean wat are the pin of the colour lcd panel are for(like some control certain pixel, any that controls the colour or any other pins that do other things)?

sorry for poor language
 

3dluvr

Member
I have two of those displays, though I havent got a chance to connect them to anything yet (work is keeping me busy). They are "plain" RGB+H/Vsync displays and as someone noted above, 512 colours (3 bit per component R/G/B).

So you will need to feed it RGB signal along with H/V sync with appropriate timings. Since the spec sheet is available and includes all timings, my plan is to get it connected via a PIC or AVR (a faster one mind you) that will generate an output image with perhaps composite video as an input or some other source (maybe internal character generator program inside the PIC/AVR).

Personally, connecting them to the parallel port would be a waste and not too portable, especially when you need a whole computer to drive it. I'm not sure if parallel port can push enough bits to generate the full size image on the display without the use of a frame buffer circuit and what not, so there's more circuitry invovled.

I feel that using an AVR or PIC circuit can replace the frame buffer and parallel port. But that's yet to be done (at least here), perhaps someone else has already done it, thought in all my search of the Web I havent found any similar projects to draw any ideas from.
 

sgboi

New Member
im using lcd so that i will be able to change it for other uses in future(like displaying winamp or something).

im using parallel port because i dun have to get a pic and i dun need to be portable as it is for my computer.

Thanks for all the info.

But since i have not bought the colour lcd(with module), im thinking of direct driving the a colour lcd panel that i have. Can anyone teach me how to do so?
 
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