Code for led matrix

Discussion in 'Programmer's Corner' started by Aklem, Sep 11, 2009.

  1. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    How do you define letters, scroll the words or patterns on a 7x5 display?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    The same way you would using a pencil and a 7x5 grid on paper.
     
  3. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    Wow thats deep... But i want a code example not a post that tells me the concept. I know you use arrys but i want to see the code
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    Google the word charlieplexing.

    hgmjr
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    What code? It's dependent on the array, the interfacing, and the outputting device - not to mention the language used. All these are mysteries at this point.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    I matrix the data using one byte to hold 7bits for the vertical 7 pixels on the 5x7 displays.
    Then scrolling left is performed by moving all the bytes left one space.

    So if you have a 5 digit 5x7 display it needs 25 bytes to hold the display data.

    I "define letters" using a lookup table, and write the letter to a "scratchpad" of 5 bytes which is not visible but is basically just the same as the other 25 bytes.

    Then the new letter is automatically shifted onto the visible display the next time it is shifted left one pixel.

    Hope that helps, it's a start. If anyone has a better system maybe they can mention it?
     
  7. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    I get the first part of your post, to answer your questions:
    im using a arduino
    using the arduino ide
    using a 8x8 led matrix display

    i need to have the above post clarified to fit this description, more easy to understand.
     
  8. hgmjr

    Moderator

    Jan 28, 2005
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  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Charlieplexing is very different to multiplexing. Multiplexing has only 2 dimensions and usually one is the "common" and the other is the "bits". Charlieplexing only lights one pixel at a time and has an unknown number of dimensions based on the number of pins in the charlieplexed mesh.

    Aklem, I know there are lots of Arduino examples out there on the internet doing multiplexing, i'm not sure about 8x8 displays but you can easily find 5x7 display projects.
     
  10. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    i want the code, not the technique....
    sorry but i figured it out my self....


    LOL
     
  11. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    If you know the technique the code is easy.

    It sounds like you just wanted someone else to do all the work for you because you are lazy. Or maybe you can post your code so we see how you did it and we can see that you are not lazy?
     
  12. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    Im not lazy i just am new to arrays (bit of a noob)
    im 13 and have no time to learn this fully!
    Im doing a project tbat i will have to save up for months and now im going to use a serial display.
     
  13. auri_z

    New Member

    Feb 5, 2009
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  14. Aklem

    Thread Starter Active Member

    Jun 18, 2009
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    Talkin bout code not hardware, im going to use 4 74hc595's which only needs 4 or 3 pins
     
  15. BMorse

    Senior Member

    Sep 26, 2009
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    I use a Pic16F84 and 2 4017 Johnson counters to control an 8x20 LED matrix scrolling display...... using only 9 pins total from the uc :rolleyes:.
     
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