So I cant get my simple LCD to work... :(

sirhotalot · 08-15-2002, 10:31 AM

Yes this has been asked before, I just couldnt find a suitable responce that fit my condition. I have a 24x2 lcd that I cant get to print. It is hooked up to my pararlel port using the pop. pinout diagram. This should be correctly references as I double checked it to my port pinout that came with the display. Anyway when I power it up I get the standard go signal, black boxes accross the top- but I cant get my computer to do anything on it. Not even produce garbage. Ive been trying to use lcdprint. I boot to 98 type command: lcdprint 378 it then says that my port is there. THen I type lcdprint 378 24 2 mytext.txt (i mae a textfile and placed it in my home directory, it just returns me to the dos prompt with no responce from the screen, am I missing something here? the other person who got this display (http://www.allelectronics.com/cgi-bi...-74&type=store) seemed to be doing the same thing I am and got it working! So am I missing anything? Is this a software problem or should I try and rewire? Thanks for helping me out,
Eben

bombboyer · 08-15-2002, 02:03 PM

I'm having the same EXACT problem, but mines 40x4. Heres a bump for ya.

mikeinsanmarcos · 08-15-2002, 02:41 PM

most common problem is wiring mistakes! Double check with continuity checker...

sirhotalot · 08-15-2002, 05:43 PM

Still no luck... I checke dall the connections, three times over at three different sititngs (just in case of brain fog) I cant find any soulution! The only thing I dont have insatlled are the two resistors (ones a variable 10k and the other is a fixed 100k but its for pin 16 that i don thave anyways so I dont know on that one. ) So am I stuck? Where else should I look? I know someone from that website apparently got this up and runnignwithno trouble.

Ive got all night so im up for any suggestions (no matter how timely)
Thanks!!
E

mikeinsanmarcos · 08-15-2002, 05:45 PM

do you have a link to the wiring diagram you are using?

sirhotalot · 08-15-2002, 06:05 PM

I first tried this one : http://lorty.mp3car.com/lcdcorrect_eio.jpg but that didnt seem to work since my display has fewer connectors so I switched to a similier one that wires port 1 to port 6(e) and the other sequentially from that. Reflecting on that it doesnt really mkae sence since theseprogarms must be based on the same general wireing- im going to go and try to wire it up using the one i just posted!Thanks ill be back ina sec!
E

sirhotalot · 08-15-2002, 06:11 PM

well it turns out they hook up the same. Pin 1 for me is just Vss. and my data channel starts at pin 6 (e) so it lines up straight accross....and yet my display will not respond. Sigh. Any other thoughts?

Raas · 08-16-2002, 04:22 AM

Hi,

i once was having these probs on my 4x40 too.
Seems you have to turn the contrast all the way up in order to see anything on the display..
I had the same symptoms.. triple checked everthing, and again and again, but everything seemed right.. untill I started to play with the resistor for the contrast.
suddenly, the characters became visible on the lcd.. and is working great since then.

hope this helps you out.

Greetz,

Raas

sirhotalot · 08-16-2002, 10:48 AM

Thank you! IM anxious to try this though I cant till later this weekend. Would this contrast thing still apply since I see black boxes on the toprow?

phil.45 · 08-16-2002, 11:21 AM

No, sorry. The black boxes are the equivelent of characters being displayed. If you can see them, you will be able to see other output as well.

mikeinsanmarcos · 08-16-2002, 11:57 AM

Do you have it wired like this?

lcd pin 1 = gnd (lpt pins 18-25)
lcd pin 2 = +5
lcd pin 3 = 10K pot (hooked between gnd & 5v)
lcd pin 4 = lpt pin 16
lcd pin 5 = lpt pin 14
lcd pin 6 = lpt pin 1
lcd pin 7 = lpt pin 2
lcd pin 8 = lpt pin 3
lcd pin 9 = lpt pin 4
lcd pin 10 = lpt pin 5
lcd pin 11 = lpt pin 6
lcd pin 12 = lpt pin 7
lcd pin 13 = lpt pin 8
lcd pin 14 = lpt pin 9