LCD Newbie needs help!

[Sneakzee]

Hello,
I have this cool project in process that involves hooking a C.F.
16x2 Character LCD to my parallel port. I have hooked it up and I get the "boxes" on the LCD to light up upon powerup.
The problem is that the lit up boxes don't go away.
I can see the display is recieving what I am sending it, but ever so faintly as the boxes dominate the screen. Its almost as if the "test pattern" is staying on, not allowing the message to have the nice contrast that it should have, making it nearly unreadable. Any suggestions?

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[moi]

adjust your contrast

 

[Sneakzee]

3rd pin grounded

I read the 3rd pin being grounded is suppose to give greatest contrast. I have mine grounded, do I need to adjust voltage to this pin to try different contrasts? I will verify tonight that the ground is good. Any other tips on contrast would be great,
Thanks.

 

[Sneakzee]

Snoopin around

Well the more snoopin around I am doing the more it looks like I need to wire up a 10K pot. to the contrast line. If any of you out there with morew LCD experience think I'm on the right/wrong track let me know.

 

[coolguy982]

did you get this resolved?

I'm having a similar problem. Did you ever get your problem figured out? Did you ground the 3rd pin or give it a certain voltage?

 

[CF Support]

Good wiring guides for HD44780 compatible LCD's can be found:

http://www.myrolypoly.com/lcd_project/lcd_project.html

http://www.icehw.net/article.asp?id=104

http://www.geocities.com/ResearchTriangle/1495/ee_lcd.html

http://www.overclockers.com.au/techstuff/a_diy_lcd/

http://www.hardforum.com/showthread.php?threadid=248302

You can also go to http://forums.bit-tech.net/showthread.php?threadid=5582 and search for "assuming alphanumeric" and you will find a short Q/A post on parallel displays.