led dot matrix urgent

Discussion in 'Homework Help' started by inzaghi, Dec 18, 2006.

  1. inzaghi

    Thread Starter New Member

    Dec 17, 2006
    1
    0
    Hi every one:D ;
    i am new to this forum and i am currently undertakin an electrical engineering degree and i thought it would be a good idea to join.
    I have a problem to program the pic 18f4620 to control the led dot matrix. Actually I have to design the led billboard just like display at outdoor. Firstly, I just wanna to learn how to control the led dot matrix 7x5(juz 1 frame for 1 character)..but its not success. For ur information Im using pic18f4620 and shift register(74hc595) to shift the data(spi concept)..i also using MicroC compiler to write my program(c programming)..
    For example I want to display the character R and it will scrolling (moving to the left).i already attach fail for discription about my project.anybody can help me??
     
  2. itsahc

    New Member

    Feb 3, 2008
    1
    0
    can you help me by explain how to coding the programme to show capital letter 'A' .Maybe u can tell me the concept how its work
     
  3. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    Usually, billboards use a column select, then activate the rows in order to display a single line (part of a letter). Then, the column is incremented, then another line is displayed. This is done quickly and is part of a loop structure. You need look-up tables to create the letters out of individual lines.

    Your method is a bit confusing. It seems a bit more tailored to using large displays, since you're using 3 outputs from your microcontroller, plus a lot of unnecessary complexity, to achieve what you can do easily with two more outputs.

    You need to do this line by line. So, write a single column, send the serial data to write a 00000001. Write the next column, send 00000010, etc. Try to find an elegant way to do this in a loop structure, so that you can use it for larger arrays of letters.

    goodluck,

    steve
     
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