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just can't get the matrix to work. (Read 11294 times)
04/01/07 at 18:27:53

palDAU   Offline
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ok, i am not an electrical engineer.  just an architecture student.  for the life of me, i can't get the matrix to work with the maxim7219.  i've tried it with both the arduino and the wiring board.  i can get it to light up, i can get it to change.  but there does not seem to be any rhyme or reason to any changes that i make.

i have tried the simple matrix and sprite libraries.  they do stuff, but not what i think they are intended to do.  they pretty much freak out and flash(not in a good way) or just blink the entire matrix on or off. 

is it possible that i have fried the maxim chips?  i have been playing around with different power levels from none(just whatever gets there from being plugged into the datain, load, and clock) to 5v in the V+ and 10k RS +5V in the ISET.  it obviously gets brighter when i have it hooked up to the 5V, to the point where is is always on and seems not to change at all.

any help would be greatly appreciated.  i am probably just missing something stupid here.  and i do believe the matrix is built properly.  i can get every individual light to go on on its own without the use of the maxim.
 
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Reply #1 - 04/01/07 at 19:03:14

barragan   Offline
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Please post pictures of your connections and code to help you better.
 
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Reply #2 - 04/01/07 at 19:56:20

palDAU   Offline
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i am just using the simple matrix and sprite code from the built in libraries.  they do different things, for sure.  the delays seem to work(meaning they will blink faster), but i don't seem to have any control over brightness control or changing the srpite in any meaningful way. 

for example, am i wrong in assuming that:
myMatrix.write(1, 5, HIGH);
means that the pixel in the first column and five rows down will be turned on, etc.

also, i don't seem to have the option(or don't know how) to upload pictures at this point, sorry.


Matrix myMatrix = Matrix(0, 2, 1);

void setup()
{
  myMatrix.setBrightness(15);
}

void loop()
{
  myMatrix.clear(); // clear display

  delay(100);

  // turn some pixels on
  myMatrix.write(1, 5, HIGH);
  myMatrix.write(2, 2, HIGH);
  myMatrix.write(2, 6, HIGH);
  myMatrix.write(3, 6, HIGH);
  myMatrix.write(4, 6, HIGH);
  myMatrix.write(5, 2, HIGH);
  myMatrix.write(5, 6, HIGH);
  myMatrix.write(6, 5, HIGH);

  delay(100);
}
 
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Reply #3 - 04/02/07 at 05:17:19

barragan   Offline
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hi, there is a small button in the bar when you're posting a message in the forum, actually it is the third button for inserting images, when you press it it includes in the text a couple of tags, put a valid url containing the picture in between the tags, and that's it. You can point in this way to any URL where you upload the picture.
Yeah that's the Matrix example code, Wires ging from wiring pins 0, 2 and 1
for Matrix(data, load, clock) meaning 0 goes to the data pin in the controller, 2 goes to the load pin and wiring pin 1 goes to controller clock pin.
Yes the pixels are specified in x (column) y (row).

 
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Reply #4 - 04/02/07 at 17:05:24

palDAU   Offline
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ok.  Thanks.  here's the photos of my setup.
...
...
...

i do not have extra 5V going to this setup.  just the ground.  i've tried switching the 1 and 2 pins.  there seems to be some discrepency between the library code and the code in the samples built in to wiring as to whether load or clock is 1 or 2.  bur, regardless, i've tried both ways without consistent results.

is it possible that the chips are shot?  i've tried 2 chips with the same code and i get different results...but still results that don't seem to correspond to changes in the code.

thanks man.  any help here is greatly appreciated.

andy
 
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Reply #5 - 04/03/07 at 03:56:55

barragan   Offline
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hi Andy, wow it's difficult to see the connections from the pics, is it possible for you te take a picture from the top of the breadboard? or maybe draw a diagram of what you have connected or still better draw on top a picture if the case. In the meantime I'll get a chip and will draw a nice diagram for the page, wiring style diagram Smiley like those in the examples.
 
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Reply #6 - 04/03/07 at 18:21:07

palDAU   Offline
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hey,
this is what i've got going.  i've tried with the additional 5V(and 10k RS) and without.  with the additional it seems to be too much power, i think.  the whole grid lights up bright and does not even go off during a reset.  without the additional power i can get it to blink and such, just not with any reasoning.

thanks for looking into this.  much appreciated.

andy

...
...
 
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Reply #7 - 04/04/07 at 23:34:43

barragan   Offline
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hi, sorry for the delay, I'll be working on your diagram tonight. Smiley
 
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Reply #8 - 04/05/07 at 00:41:22

palDAU   Offline
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no problem.  at your leisure.

if it makes a difference in the power consumption, i am using the following LED's

http://www.vishay.com/docs/83028/83028.pdf

thanks.

andy
 
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Reply #9 - 04/05/07 at 05:02:19

barragan   Offline
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hi Andy, please tell me what led matrix are you using. Anyway, here is a diagram, I'll re-check it out tomorrow. http://wiring.org.co/learning/examples/hello_matrix.html
« Last Edit: 04/05/07 at 07:48:15 by barragan »  
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Reply #10 - 04/05/07 at 05:37:58

palDAU   Offline
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i built my own.  i am quite sure that it works(famous last words).  i have tested each individual LED per row and column (cross reference without the use of the maxim chip).  just plugged them in as you would any LED. 

looks similar to this...
http://www.alexcicciu.com/blog/lightmatrix3.html
although this is not mine.  just don't have a picture handy right now.
 
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Reply #11 - 04/05/07 at 16:14:33

palDAU   Offline
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wow!  thanks man.  that looks great.  i realized i'm was missing the 2nd resistor on the load side.  it seems to be working, kind of.  the patterns seem to be in order from the libraries.  the only problem is that the LEDs that are supposed to be off are only at about half power.  the ones making the patterning are at full luminosity.

i suspect there is a power issue still.

...(ten mintures later)

it's not a power issue.  i had the rows and columns backwards!  i'm an idiot.

man, this is great!.  thank you so much.

you will be credited clearly in my project for this semester.  i can't thank you enough.


andy
 
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Reply #12 - 04/06/07 at 04:44:56

barragan   Offline
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hey Andy, I am very glad things worked out for you, let me know about your project, it would be great to have it on the exhibition section. Smiley
 
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