MAX7219 8X8 not working

Hi,
i have the MAX7219 and 8X8 display,
i tried to connect it but i get static output
Pictures of the problem
Someone know the problem? has my hardware ok?
this is my code http://pastebin.com/ccLX1UV5
if you need anything more to solve the problem tell me :smiley:
thanks for reading


Could it be you have your anodes and cathodes swapped?

Have you tried an example sketch from a 7219 library to be sure everything is wired correctly?

Double check your wiring.
I don't see any de-coupling, do not omit them !

johnwasser:
Could it be you have your anodes and cathodes swapped?

No, there would be no display at all.

johnwasser:
Have you tried an example sketch from a 7219 library to be sure everything is wired correctly?

That is what he posted; I have tested it and it working here just fine.

OK, we need to know what happens at various steps.

Unplug the USB cable and plug it in again. What does the display show immediately? What does it show after a couple of seconds? Does it change thereafter?

Press the Reset button - does anything change?

Open the Serial Monitor - what do you see?

It would really help if you posted a focused photograph of your setup. As best I can see it amidst all that blur,
However, I think I can see the problem (with great difficulty!)

Pin 10 of the Arduino is going to pin 1 on the 7219 - data in.
Pin 11 of the Arduino is going to pin 24 on the 7219 - data out
Pin 12 of the Arduino is going to pin 12 on the 7219 - load

That isn't going to work.

Pin 10 of the Arduino must go to pin 12 on the 7219 - load
Pin 11 of the Arduino must go to pin 13 on the 7219 - clock
Pin 13 of the Arduino must go to pin 1 on the 7219 - data in.

And you should have a 22k resistor pulling pin 12 of the 7219, high, to avoid spurious data being loaded before the Arduino initialises.

Paul__B:

johnwasser:
Could it be you have your anodes and cathodes swapped?

No, there would be no display at all.

johnwasser:
Have you tried an example sketch from a 7219 library to be sure everything is wired correctly?

That is what he posted; I have tested it and it working here just fine.

OK, we need to know what happens at various steps.

Unplug the USB cable and plug it in again. What does the display show immediately? What does it show after a couple of seconds? Does it change thereafter?

Press the Reset button - does anything change?

Open the Serial Monitor - what do you see?

It would really help if you posted a focused photograph of your setup. As best I can see it amidst all that blur,
However, I think I can see the problem (with great difficulty!)

Pin 10 of the Arduino is going to pin 1 on the 7219 - data in.
Pin 11 of the Arduino is going to pin 24 on the 7219 - data out
Pin 12 of the Arduino is going to pin 12 on the 7219 - load

That isn't going to work.

Pin 10 of the Arduino must go to pin 12 on the 7219 - load
Pin 11 of the Arduino must go to pin 13 on the 7219 - clock
Pin 13 of the Arduino must go to pin 1 on the 7219 - data in.

And you should have a 22k resistor pulling pin 12 of the 7219, high, to avoid spurious data being loaded before the Arduino initialises.

Unplug and plug nothing change

Serial Monitor says
Setup
LED0: 0 0
LED0: 0 7
LED0: 7 0
LED0: 7 7
LED0: 0 0 off
LED0: 0 7 off
LED0: 7 0 off
LED0: 7 7 off

Reset button nothing change

it is connected as you say
Pin 10 of the Arduino must go to pin 12 on the 7219 - load
Pin 11 of the Arduino must go to pin 13 on the 7219 - clock
Pin 13 of the Arduino must go to pin 1 on the 7219 - data in.

i dont have any 22k resistor i have only 220,10,1

What do you mean by "220,10,1" ?

220R or 10R or 1R or 1K would be way too low. 220K would be way too high. 10K should be ok.

Paul

i add the 10K resistor nothing changed

hyuval1511:
it is connected as you say
Pin 10 of the Arduino must go to pin 12 on the 7219 - load
Pin 11 of the Arduino must go to pin 13 on the 7219 - clock
Pin 13 of the Arduino must go to pin 1 on the 7219 - data in.

Well, it certainly does not look as if it is connected that way in your blurry photograph.

Can we have a focused photograph of the Arduino and the breadboard(s) please? Hint: Use the maximum zoom on the camera and hold it at least a metre away in good daylight. If the answer to the following question is "Yes", then it does not need to be powered up for a photograph.

Does the matrix always show the same pattern? If so, that proves the wiring is wrong.

Paul__B:

hyuval1511:
it is connected as you say
Pin 10 of the Arduino must go to pin 12 on the 7219 - load
Pin 11 of the Arduino must go to pin 13 on the 7219 - clock
Pin 13 of the Arduino must go to pin 1 on the 7219 - data in.

Well, it certainly does not look as if it is connected that way in your blurry photograph.

Can we have a focused photograph of the Arduino and the breadboard(s) please? Hint: Use the maximum zoom on the camera and hold it at least a metre away in good daylight. If the answer to the following question is "Yes", then it does not need to be powered up for a photograph.

Does the matrix always show the same pattern? If so, that proves the wiring is wrong.

you will not able to see nothing if i will take a photo
the matrix always show the same pattern can you give me a good datasheet for this so i can check if my wiring is wrong

Paul__B:

johnwasser:
Could it be you have your anodes and cathodes swapped?

No, there would be no display at all.

Are you sure on that?

Per the datasheet:

When the MAX7219 is in shutdown mode, the scan oscil-
lator is halted, all segment current sources are pulled to
ground, and all digit drivers are pulled to V+, thereby
blanking the display.

On initial power-up, all control registers are reset, the
display is blanked, and the MAX7219/MAX7221 enter
shutdown mode.

So my guess is that on a Common Anode, weird LEDs work. My further guess is that sending the all segments on command would blank the display if it were Common Anode.