RGB 16x32 Panel
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RGB 16x32 Panel

by Mk- on Thu Dec 06, 2012 1:11 pm

Hey there, i recently bought a 16x32 RGB LED panel from adafruit for a project. with the tutorial and libraries posted I had it up and running in like 30 minutes (excellent btw!)

However, several days later after I was working on some of my own code to run on the panel, everything seemed to die. It was working fine, then the next time I uploaded code everything just seemed to go awry.

First every other row of the panel was not lighting up, but if I fiddled with the crimp connector between my breadboard and the arduino, the rows that were off would come back on a bit, though still not the right colors or consistently. I figured maybe something was wrong with that so I recrimped the wires and retried.

The problem seemed to manifest itself differently with the pixels on the rows being offset from where they should be. I rebuilt the circuit entirely and with a new arduino and the same problem existed.

I am wondering if there is something wrong with the controller itself at this point?

Any suggestions for further troubleshooting? also do you happen to have a schematic of the circuit so I can try to isolate where the problem is exactly?

Any other suggestions on what I could try? I'm wondering at this

edit- just to make it clear, I am still using an unchanged version of the adafruit libraries used to run things, and running the basic built-in examples to test.
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Re: RGB 16x32 Panel

by pburgess on Thu Dec 06, 2012 1:18 pm

If you can post photos of the wiring and the display artifacts, we might be able to better diagnose the trouble.

Sounds like an intermittent connection in the row address select wires.
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Re: RGB 16x32 Panel

by Mk- on Thu Dec 06, 2012 1:34 pm

The wiring is the same as the tutorial, I just changed the latch to D13 in order to utilize 5 concurrent pins on the C port to read some inputs.

That is updated in the examples before I upload them

Code: Select all | TOGGLE FULL SIZE
#define CLK 8  // MUST be on PORTB!
#define LAT 13
#define OE  9
#define A   A0
#define B   A1
#define C   A2
// Last parameter = 'true' enables double-buffering, for flicker-free,
// buttery smooth animation.  Note that NOTHING WILL SHOW ON THE DISPLAY
// until the first call to swapBuffers().  This is normal.
RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, true);



The picture below is the draw shapes example, it should be an X across the screen
https://www.dropbox.com/s/azf2550yg2j3coz/2012-12-06%2013.26.03.jpg

(too large to upload)

And the address indeterminacy is what I was thinking as well. (that or clock possibly?)
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Re: RGB 16x32 Panel

by pburgess on Thu Dec 06, 2012 2:08 pm

I've had a couple of ribbon cables where the IDC connector wasn't crimped on quite right, from the factory. If you have a meter available, might want to check these lines for continuity.

Also, to confirm, your changed wiring (with LAT on pin 13) did function at least temporarily?
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Re: RGB 16x32 Panel

by Mk- on Thu Dec 06, 2012 2:33 pm

Yea, I thought the same thing about the IDC connectors, I pulled them off and recrimped them further down the cable and then hotglued the connectors back in place (the plastic was not meant to be uncrimped, got 1 without the plastic part on the side breaking, but not the other)

I verified all the pins and all made good connection.


Changing the pins did work just fine for a few days, so i cannot imagine that could have messed anything up now.


I'll try and redownload the libraries in a bit and see if I possibly could have overwritten anything when I was reading through the code that drove them. Other than that and one of the arduino pins being bad i really dont know what else it could be. I'll be checking the pins next to make sure they all write out correctly.

Any other ideas?
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Re: RGB 16x32 Panel

by pburgess on Thu Dec 06, 2012 3:03 pm

Please test one of the example sketches with it (changing the latch pin, obviously, but keeping the rest the same). Thanks!
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