HD44780 not working - maybe blew it...

**kaine** · 05-22-2004, 09:59 PM

Okay I have a HD44780 LCD screen. I just got finished soldering it to the female end of a M/F 8-bit parallel cable. All the solder is okay, and the wire is tight, and doesnt move or anything. I set up my home pc to run it. I installed and configured the Winamp plugin and I know that works cuz I can get the onscreen test working. But whenever i set the plugin to output to the HD44780 lcd screen I get nothing. No pixles no lines nothing. I am afraid I mighta fried it from not grounding myself or somethin. I keep getting the error: "Error accessing LCD". What else could be the problem? (besides the lcd is fried, cuz Ill be screwed no matter what then).

**Q_gamelogic** · 05-22-2004, 10:12 PM

so it works , but doesnt when you use a winamp visual?

sounds like a resolution , refresh rate or (if its not VGA .. an output problem)

**dignome** · 05-22-2004, 10:13 PM

I realise the error message probably is not a good thing and is most likely the source of the problem, but just for a quick question, what are you using to control the contrast on the lcd? Are you doing the potentiometer method or crossing pins? Or maybe something else?

**Q_gamelogic** · 05-22-2004, 10:32 PM

you can use the computer's video card to control that ....

i dont know about THAT screen specifically .. but doesnt it have that thing like brightness and contrast settings inbuilt??? (when you press menu or whatever? )

**dignome** · 05-22-2004, 10:38 PM

He's talking about something entirely different. The hd44780 based liquid crystal display module is a character based display, meaning it will show ascii character text and possibly other symbols. You measure these in lines, not pixels ;p

http://www.overclockers.com.au/~mwp/...44780-40x4.htm

http://www.moddershq.net/guides.asp?guideid=13

Some of them have backlights and whatnot.

**kaine** · 05-22-2004, 10:57 PM

wow thanks for the responces, Ive messed with the contrast controls in the winamp plugin, but it had no effect. There was a blacklight option but it required extra wiring i think. Like i said it is interfaced on an 8-bit parallel port. I have not seen it turn on at all.

**Q_gamelogic** · 05-22-2004, 11:08 PM

ahhhhh yes yes ,,,, ooopsy LOL

**Marsupial** · 05-25-2004, 10:32 AM

Kaine: when you apply power to the HD44780 - without plugging it to the computer. Do you get test blocks?

also, how do you power it?

**Superduck** · 05-26-2004, 03:05 AM

Providing you did get the test blocks, did you install the Port I/O driver? I seemed to always have problems getting everything set up properly to drive the LCD's. I messed with settings and drivers then suddenly it just worked.

Again, if you don't even get the blocks on the screen, then you've got to go back to checking all your connections. You'll have to methodically test each connection with a mulitmeter, probably. I only just started wiring up my second LCD, a 20x4. My first one was an 8x2 which seemed almost useless for what I wanted it for, so I sold it. I've got all the different programs and drivers that I downloaded to make it work, if you need them. Otherwise they're all available online.

Let us know how it goes.

Regards,

Kris

**Meltz014** · 03-11-2005, 05:53 PM

Providing you did get the test blocks, did you install the Port I/O driver? I seemed to always have problems getting everything set up properly to drive the LCD's. I messed with settings and drivers then suddenly it just worked.

what is this Port I/O driver you speak of. I can get the test blocks and whatnot, but i cant get past that. i think the problem is with the drivers on my lpt port