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2 by 16 lcd problem — Parallax Forums

2 by 16 lcd problem

cwaugh18cwaugh18 Posts: 4
edited 2010-01-30 03:18 in BASIC Stamp
Hey- I just bought a new bs2 and 2 by 16 backlit lcd. I am currently having a problem though, it's kinda weird- here is what happens:

I turn on the lcd and it shows dashes and numbers in random spots and sometimes squares blink on and off. However if I unplug the lcd and reconnect it, the dash moves over the left hand corner. Then I do a reset on the BOE and the LCD works perfect. But then randomly as I am working with it, it will suddenly dim off and then go back to the numbers.

Sometimes I have to keep redoing process number one for it to work again. And sometimes it will work perfect until I power off the BOE and repower it on.

Any idea of what's happening? Could it be a short in extension cord causing the RX not to be reliable? Let me know if you want a pic of the LCD with the weird symbols and numbers.

-Chris

Comments

  • FranklinFranklin Posts: 4,747
    edited 2010-01-03 05:31
    Check the power to the LCD. I don't think the stamp can power it from it's regulator. You may need to power the LCD from it's own source.

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    - Stephen
  • cwaugh18cwaugh18 Posts: 4
    edited 2010-01-03 05:34
    It used to power from the regulator just fine until that one burned out from an electric surge. This is a brand new one causing me problems. But I can check the power... any other ideas?
    -chris
  • cwaugh18cwaugh18 Posts: 4
    edited 2010-01-04 00:22
    Okay- Tried changing the power source and it made no difference- any other ideas? I really want to get this fixed...
    -chris
  • Tony B.Tony B. Posts: 356
    edited 2010-01-04 17:02
    Chris,

    You need to provide some more information for forum members to be better able to help you. How do you have the LCD connected to BOE? What are your baud rate DIP switch settings on the back of the LCD? What code are you trying to run? You can save your code in the Basic Stamp Editor as a file and attach it to a post.

    What is your power supply and what have you tried? Have you verified that the power pin to the LCD is a 5v?

    I have a BS2 on a BOE connected to a 2 x 16 Backlit LCD through the servo connectors (X4) pin 15. This configuration works well. Have not run with backlight on but don't see why that would be a problem because the LCD with backlight on only draws 80mA (page two of manual) and the BOE regulator can supply 1A.

    I suspect you problem may be that the the stamp is sending the serial data before the LCD is initialized. When you unplug the LCD and then plug it back in it works because it is initialized and ready to recieve serial data. If this is the case a short pause (pause 2000) at the beginning of your code will give the LCD time to initialize.

    Hope this helps
  • cwaugh18cwaugh18 Posts: 4
    edited 2010-01-28 23:34
    Hey- I tried that and it still didn't work... it doens't always work when I unplug it and plug it in.... sometimes it does though... it seems when it finally works it works until the boe is reset... any other ideas?

    I have 1 set to off and 2 on... and the baud rate is 84... i think that is 9600

    Again, the LCD is brand new so i can't see it being wrecked... could it be a short in the extension header cable? I don't have another one too test it...

    -chris
  • Tony B.Tony B. Posts: 356
    edited 2010-01-30 03:18
    Chris,

    Could you please post your code as I described above. It would really help to see what your trying to run.

    What does the LCD display show when you set the dips to both off for test mode and apply power through your extension cable? Look at page 5 of the LCD manual.

    Is the extension cable the ones sold by Parallax?

    Tony
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