DUE and the MAX7219

Hi guys,

I'm trying to drive 4-digit 7-segment display with it. I'm having problems running a code with the default LedControl library on DUE.

The code works on UNO/MEGA, but fails to do so on DUE. There's a little flash of the number, but nothing more.

I'm defining it like:

LedControl lc=LedControl(8,9,10,1);

...

lc.setDigit(0,3,0,false);

And then just setting a number. This works on UNO, but not on DUE. I'm powering the MAX7219 from 5v (tried both from DUE and external 5v, without success.

I'm thinking, if the levels are low (3.3v) on CLK, DIN and CS? Is it possible? I saw some guys had success on this. My RSet = 9.4k

Please, help!

A little update:

  1. 3.3->5v voltage level shifter did not help.
  2. Numbers 1, 4, 7 DO display correctly. All the others do not :frowning: The same code still works perfectly in UNO/MEGA ...

Okay, I finally found the problem. It turns out that I was missing 100nF capacitor between 5V and GND near display. When it was far from it, it failed. When I moved it close to the display, it's working perfectly and stable.