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LCD help

turboEK2000turboEK2000 Posts: 18
edited 2006-04-08 02:11 in BASIC Stamp
Hello I just bought a bastic stamp a few weeks ago and I·can't stop·playing with it ever since.... anyway

I just got this emerging displays technologies LCD screen with the same hitachi driver as the parallax one on the back and the pins and everything are also setup the exact same way.. I'v tried about 3 different example programs to try and get this this to say something but I·CANNOT get this thing to work, I wired it·about 5 differnt times, i used the program and scematic in the Stamps In Class thing and it still dosen't work, is there anyway I can get like 1 character or dot to light to see if this thing works???

Thanks
Mike

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-07 03:02
    Mike,

    Can you post a link to the technical information to the LCD you have?

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    Jon Williams
    Applications Engineer, Parallax
  • turboEK2000turboEK2000 Posts: 18
    edited 2006-04-07 03:05
    I got it from·ALL electronics...

    heres the link to the pdf file

    http://www.allelectronics.com/spec/LCD-97.pdf
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-07 03:08
    Do you have the contrast input setup correctly?

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    Jon Williams
    Applications Engineer, Parallax
  • turboEK2000turboEK2000 Posts: 18
    edited 2006-04-07 03:26
    I have a 10k resistor connected to Vdd and VO which is the "lcd contrast for logic circuit" and still nothing...
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-07 03:43
    I have to pop by All Electronics tomorrow, anyway, so I'll pick up an LCD and give it a try.

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    Jon Williams
    Applications Engineer, Parallax
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-07 04:24
    turboEK2000 said...
    I have a 10k resistor connected to Vdd and VO which is the "lcd contrast for logic circuit" and still nothing...
    This is most likely your problem.· The "pot" needs to be connected to ground as well.· You're basically pulling Vo high (vdd), which will give you the least amount of contrast.· The more towards 0 volts the more contrast, so you need to also add a resistor to Vss to provide a ground reference.· It wants to see about 1.5V at Vo and you're basically providing 5V.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • turboEK2000turboEK2000 Posts: 18
    edited 2006-04-07 16:39
    wow THANKS I just got it to work, this crappy scematic that came with the lcd was screwing me up

    It said recommended resistor R: VDD- VO greater then or = to 1.5V

    I get it now so, I could just ground it and it will be on all the time correct???
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-04-07 16:42
    You shouldn't do that -- keep the pot in so that you can adjust contrast as needed.

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    Jon Williams
    Applications Engineer, Parallax
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-07 19:22
    On some LCD Modules you can connect the Vo line to Vss and everything will work fine since that is usually maximum contrast, however your datasheet specifically describes a minimum voltage.· Tying it to ground would violate that recommendation.· When in doubt follow the datasheet.· On top of that having the contrast pot installed is always a good idea because variations in each module and temperature can affect the contrast setting.· In many cases that can cause blocks on the screen and you won't be able to read the text.


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com


    Post Edited (Chris Savage (Parallax)) : 4/7/2006 7:27:37 PM GMT
  • turboEK2000turboEK2000 Posts: 18
    edited 2006-04-08 02:07
    yea I have the pot setup anyway, thanks, does anyone have a peice of code that I can use to start off with, like something really simple, because I'm trying to modify some code I got from the Stams in class site, but its to complicated, so I can build on it and make my own projects
    thanks
    Mike
  • SSteveSSteve Posts: 808
    edited 2006-04-08 02:11
    There are a couple examples in the StampWorks manual. They were very helpful for me.

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