Friday, March 18, 2011

Project 21 - LED Dot Matrix Display - Scrolling Message FIXED

This project's been driving me crazy... the code makes total sense and I couldn't find any errors with my wiring.

So I just knew it had to be a bad chip or a bad 8x8 display... because there's simply no way it could be my mistake, right?

Well, if I'd looked at the very small writing on the side of the 8x8 display I would have seen the letters TA15... on the other 8x8 are the letters TC15... I wonder what those letters mean?

This project calls for a Common Cathode... with a C. Earlier projects used a Common Anode 8x8... with an A. Hand. Hits. Head. Hard.

So, here it is... with the proper 8x8 display installed... and working fine.

I'm going to go to bed early tonight.


  1. Hi Jim,
    Glad you've got it sorted now, the video is lacking sound in the middle, just something to note

  2. Nice Job James,
    Those kind of mistakes happen´s all the time with me.
    I sometimes blow up some capacitors with wrong polarization... :)
    Thank´s for sharing your experiments, evolution and problems....

  3. Hello James,

    Great Work

    Can you share the program with us?


  4. can anybody show the program for 8x8 matrix display

  5. The author's code does not work with version 1.0.3; it does work with 0023. I'll see if I can send this as errata. Unfortunately I don't have a fix..if I find one that closely resembles his code then I will post it. With that being said, I'm not sure if this code helps you to understand the LedControl library all that much honestly, but I can say that I appreciate those who create the Libraries to make functions much easier.