LCD do display - but pins check out


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  1. #1
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    Default Re: Confirmation

    Thanks for the suggestion, but I've tried taking pin 3 to grnd and +5 but it still makes no difference. I've tried wiring the LCd direct to the pins, but still no joy, so I'm at a loss, other than break all the tracks between the PIC and it's header for the LCD, but if there is an issue with the board's through hole plating or something similar then the fault could still be there

  2. #2
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    Default Re: Confirmation

    What LCD are you using?
    Regards,
    TABSoft

  3. #3
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    Default Re: LCD do display - but pins check out

    What was the board designed in...?

    Can you post the project artwork / gerbers at least ?

  4. #4
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    Default Re: LCD do display - but pins check out

    The E line should pulse Positive.

    If you were to send an "H" $48 to an LCD with a 4bit interface, you should see something like this.
    Name:  LCDOUT_2.jpg
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    Regards,
    TABSoft

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    Default Re: LCD do display - but pins check out

    Thanks for the further info guys.

    @Tabsoft - it's a 4 line 20 chr back lit display. I use them in all my projects and like I mentioned, works fine on the development board do something is screwed on the board, something that is taking the lines high or low and stopping the signals getting through.

    I've traced out the schematic and compared it to the board and there are quite a few mistakes, not with the LCD part as that pings out but some nets were missed in the PCB layout module when the schematic was converted, but this was with a custom part, so that might of been human error on my part. I'm going to redraw the schematic, and re-work the PCB layout and check everything three times before sending the gerbers off. Still I have some posh new green and white coasters to put my cup of tea on so I guess all was not wasted

    Thanks again for every ones contributions

  6. #6
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    Default Re: LCD do display - but pins check out

    Good luck there, sir.
    Nothing like PCB Coasters! I have a few myself.

    BTW what Schematic/PCB software are you using?
    Regards,
    TABSoft

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    Default Re: LCD do display - but pins check out

    I use DipTrace. Up until now it's been excellent and I've produced several working boards from it.

    To be honest I think it's 50:50 human error / software error The nets show up for the custom part in the schematic, but were missing in the layout... still having spent two days now trying to sort this I think it's passed debugging and time to start from scratch

  8. #8
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    Default Re: LCD do display - but pins check out

    Quote Originally Posted by Tabsoft View Post
    Good luck there, sir.
    Nothing like PCB Coasters! I have a few myself.
    I get some of that green felt from the fabric store and glue it on the back so they don't scratch the coffee table......
    "I have noticed that even those who assert that everything is predestined and that
    we can change nothing about it still look both ways before they cross the street"


    -Stephen Hawking

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