Are you using the RGB Matrix Backpack board? It sounds like you are using an Arduino and an IDC cable. This is the forum for the nootropic design backpack board. For help with the panel, I suggest the Adafruit forum: http://forums.adafruit.com/viewforum.php?f=47
I put the cable on order so – for now – I had to use the Uno.
It’s all good – I got it working and it’s a phenomenal LED board – I wrote several cool, simple & easy programs that look great (IMO – ha).
It looks like the cable will be here mid-week and I’ll be able to use my RGB Matrix Backpack. I was able to solder the RGB matrix backpack together correctly – the demo worked great. 🙂