max7219cng and 8x8 matrix

Other Hardware LEDs and Multiplexing
1

I am having some trouble wiring up a max7219cng and 8x8 matrix.

I am using the code and partial schematic from here Tutorial – Arduino and the MAX7219 LED Display Driver IC | tronixstuff.com .

The matrix i am using is the same as this one http://www.vcc2gnd.com/2014/04/dot-matrix-led-8x8-dots07-red-light.html .

It is difficult to say how the display is wrong but it is definitely not what the video of the sample code looks like running.

The only time i got it to display half correctly was when i wired it directly to my arduino and used the dot scanning code with two potentiometers but was left with a 2 or the rows/ columns that would not work.

I have about 4 max7219cng's and ten led 8x8 matrixes. I tried swapping out the matrix for another one and the same thing happened. I also manually wired the rows and columns to make sure the pinout and led's worked properly. I have swapped for another max chip also with no help.

I have not tried changing the pins in code for others in the thought of one of my arduino pins not working right or hooking up my oscilloscope to check that it is sending pulses.

2

I would say your wiring is incorrect then. There's only the 16 wires - 8 to anodes, 8 to cathodes. More than likely you have a pair of anode wires swapped, or a pair cathode wires swapped.
I would turn on 1 LED in one row using no-decode node, make sure the one you want on is on. Then go to 1 in the next row. Confirm all 8, then work your way up a column.