Years late, but found this thread while struggling with 8 x 8 LED matrices and MAX7221.
This subject has to be one of the most confusing. References to common anodes/cathodes, column anodes/cathodes. Common anode/cathode makes no sense with discrete LED matrices. Common row anode/cathode makes sense. Common cathode on 7-segment displays makes sense as well.
I tried a commercial (Kingbright TC15-11CGKWA ) 8 x 8 "common cathode" matrix (rows are anodes, columns are cathodes). Carefully wired it up to match the MD_MAX72xx Parola hardware scheme (columns as cathodes). Fired it up and it worked fine, but 90-degrees away from the result expected from the datasheet. MD uses a "common anode" 1088B that looks like a common column anode arrangement that might be part of the problem.
I still don't understand why it was wrong, so will be unsoldering and starting again, but for what it's worth, the Kingbright display has the part number printed on one side that looks like the bottom of the display if it was stood up vertically. Wrong -the part number needs to be on the left and Kingbright pin 1 is top left looking at the display side, pins behind.
I'm not going to try and understand why it was wrong to start with, turning it 90-degrees is a lot easier.
The MD_MAX72xx Hardware Mapper sketch helped a lot
I know this is an old thread but it's the closest match I've found for what I would like to build.
Just looking for some info to see if my idea will even fly.
I would like to build a 5 digit 7 segment display using 3mm leds. 11 leds in each segment. From what I've read, the current will be WAY too high for the MAX7219 even if I use a seperate MAX7219 for each digit.
Are their other options for me or should I see about trimming down some of the leds?