I am having a little trouble with a Max 7219 controlling an 8 x 8 LED matrix. I have previously constructed one as a hardwired cicuit so I know that the code and circuit schematic (Nick Gammons) are good.
I am now trying to cascade two 7219's and have built a second circuit on a breadboard to connect up to the aforementioned hardwired circuit but the problem that I am having is that when I upload a sketch to the breadboard circuit (which at this stage is a standalone circuit) it displays the first character perfectly (so the matrix is correctly wired) and then nothing unless I press reset or upload the code again. I have checked my wiring ,and that the one polarised 10 mf cap is correct etc but cannot find a problem. Any clues would be appreciated,
Pedro.
Update - now the problem gets more Gremlinesque 
one two char sketch is displaying correctly but others are still reacting as initially described ?