Vishay lcd initialization help

Discussion in 'General Electronics Chat' started by geekoftheweek, May 8, 2016.

  1. geekoftheweek

    Thread Starter Member

    Oct 6, 2013
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    2
    Hello all. I am attempting to get a Vishay 020n004a lcd character display going. https://www.vishay.com/docs/37312/lcd020n004ab.pdf I've tried to use the initialization I found on their datasheet for a 016n001 display, I've tried a couple different versions I've found for the ST7066 controller, and I've tried the Hitachi initialization (I know it works since I've used Hitachi based ones before).

    The datasheet claims it uses a ST7066 (or equivalent) so my question is does anyone know for sure what works to get this one going?
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,058
    3,820
    The ST7066 is cross-compatible ithe the hitachi driver. It just has some extra capabilities.

    The ST7066 has pin function compatibility with the HD44780, KS0066U and SED1278 that allows the user to easily replace it with an ST7066.

    https://www.sparkfun.com/datasheets/LCD/st7066.pdf
     
  3. dannyf

    Well-Known Member

    Sep 13, 2015
    1,819
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    If vushay says so, it must use a st7066, a Hitachi clone

    A gazillion things could have gone wrong here. Without you helping others help you, no one can help you
     
  4. geekoftheweek

    Thread Starter Member

    Oct 6, 2013
    42
    2
    Thanks Gopher. I checked it out again and still can't seem to get it to work. I'll be checking my connections again to make sure I have things wired up the way I think I do. I have to be missing something obvious!!
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Can you post your code?

    John
     
  6. ElectronicMotor

    Member

    May 1, 2016
    53
    6
    Yea, I've just been messing around with these. This got me going.
    LCD Matrix - HD4478U.jpg
    Also, there is a contrast pin, labeled Vo on my device. Tie this to ground through a 4k7 resistor or you wont see anything. I fell backwards when I realized it was working all along, I just couldn't see it !
    Here's the full data sheet.
     
    Last edited: May 9, 2016
  7. dannyf

    Well-Known Member

    Sep 13, 2015
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    The nice thing about those devices is that even when they are not working, they still give you clues as to why.
     
  8. ElectronicMotor

    Member

    May 1, 2016
    53
    6
    Here's another data sheet closer to my module.
    My jump off point. These modules, whether they be in Cordless Phones, Video Players, or whatever, seem to have a pretty standard pin-out and programming algorithm, possibly because Hitachi are one of very few who make these controllers.

    o_O
     
  9. geekoftheweek

    Thread Starter Member

    Oct 6, 2013
    42
    2
    Thanks again all for the comments. I have a feeling this is going to be one of those things that if I leave it sit for a couple days and come back to it I'll see the problem. Sometimes I just need to take a break and everything falls into place.
     
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