I built my own mini LED matrix. One with a common anode and one with common cathode. The common cathode works brilliantly, the common anode, well I can't get it to work at all. Attached is the schematic for what works and doesn't. So it looks like I can get either a new set of LED matrix's or the 7221's. I can't think of a way to get this to work any other way...
I don't know what I have to do,
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16