Scrambled display

Store Forums Digit Shield Bugs/Problems Scrambled display

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  • #462
    gibbs
    Member

    Hello,

    Ive have attempted to make the digitshield on a breadboard to do some testing before ordering one. I have followed the schematic with the only difference being I am not using the same display (I have one 4 digit display) and I am not using any decimal points.

    I have it working partially but I am getting some strange behaviour.

    Here us my sketch

    #include 

    void setup() {
    DigitShield.begin();
    }

    void loop() {

    int n = 8888;

    DigitShield.setPrecision(0);
    DigitShield.setValue(n);


    }

    and here are my results (- = digit not on)

    Variable N Output
    8888 8888
    1 -111
    2 -222
    3 to 9 exhibit the same behaviour as 1 and 2
    10 1000
    11 1111
    12 12 backwards 6 backwards 6
    13 1333
    14 1444
    15 1599
    16 1688
    17 1777
    18 1888
    19 1999
    20 2088
    21 21 backwards 6 backwards 6
    22 2222
    23 23 backwards 6 backwards 6
    24 2488
    25 2588
    100 0000
    1000 0000

    Any help would be great

    14 1444

    #932
    Michael
    Keymaster

    Are you changing the value of n in your sketch somewhere? I don’t see any change…

    I guess all I can ask is “are you sure you have it wired correctly?” because if you’re using different display hardware, it will have a different pinout… Is it common anode display?

    #935
    gibbs
    Member

    Hi Michael,

    Sorry I was changing N manually and then re-uploading the sketch. I am using a common anode display with 12 pins (7 segments, colon and 4 digits) and have got each digit displaying correctly in at least one case so I think it might be a software rather than hardware issue (I have double checked the wiring but I will have another look!)
    I will have a poke about the library and see if its something to do with precision or the lack of decimal points.
    One think that is really confusing me is the Backwards 6 (lighting up all segments except the top-left vertical) is this used anywhere as an error code?

    Thanks for you help

    Dave

    #1079
    Michael
    Keymaster

    The library is designed to work with the Digit Shield hardware, so if your circuit doesn’t work, then it’s because your circuit/hardware is different from the Digit Shield somehow. How can it be a “software problem”? Obviously the software is working with the Digit Shield — it’s been on the market for almost a year. I’m not sure what you are trying to accomplish with your testing — are you unsure whether the library will work with the Digit Shield? It does!

    It’s not possible to display a backwards 6 with a properly connected 74LS247 chip, so I have no idea how that is being displayed. Have you consulted the datasheet?
    http://www.datasheetcatalog.org/datasheets/480/337938_DS.pdf

    #1081
    gibbs
    Member

    Hi Michael,

    I apologise, I wasnt suggesting your library was at fault merely that perhaps my hardware modifications were incompatible with your library due to the lack of decimal points.

    Ive had a look at the data sheet and I agree a backwards 6 should be impossible so I will continue looking for a mistake in my wiring.

    thanks for you help

    #2160

    I downloaded the DigitShield zip file and installed the library in my main Arduino libraries folder. When I open the “SetDirectExample” and compile, I receive the following error:

    #2157
    Michael
    Keymaster

    what error? I don’t see anything in your post.

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