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

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

    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 ( 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,

  • #2
    I'm having the same EXACT problem, but mines 40x4. Heres a bump for ya.
    Silver 1999 Nissan Pathfinder!
    Completion: [*********-] 90%
    Everything working! Mobile MP3s ROCK!
    LEFT TO DO: Improve power on circuit, fix slow boot time

    - 550mhz PIII on Abit BH6
    - 128MB RAM
    - 40x4 Backlit Character LCD
    - 17 key numeric keypad - Repainted buttons
    - 2.1GB laptop drive for OS
    - 4.3GB drive for MP3s Redesigned, new pics!


    • #3
      most common problem is wiring mistakes! Double check with continuity checker...
      1999 voyager pontoon boat
      (soon to be computerized)


      • #4

        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)


        • #5
          do you have a link to the wiring diagram you are using?
          1999 voyager pontoon boat
          (soon to be computerized)


          • #6
            I first tried this one : 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!


            • #7
              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?


              • #8
                you need resistors


                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.


                Raas - The Netherlands
                ME: VIA epia m10000, lilliput 7', opus 150w, 80gb<br>
                GF: IBM Thinkpad 380, ext. 3.5 80gb, 40x4, PB-IR


                • #9
                  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?


                  • #10
                    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.
                    (=========-) 99% complete
                    AMD K6/2 500 @ 450mhz to keep heat and power usage down, 64Mb, slim CDrom drive, 64mb USB pendrive for MP3 transfer, 10Gb 2.5" drive for MP3, USB>RS232
                    All jammed in external CDROM drive case.
                    Kenwood KVC-1000r In-Dash LCD. x-10 MouseRemote. Destinator V2 Gps. DC-DC with onboard Shutdown controller.


                    • #11
                      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
                      1999 voyager pontoon boat
                      (soon to be computerized)