Mike said:
Yes, the NPN transistors are turned on with an "active high" signal required for Charlieplexing columns with common anodes...
The reason I asked is a NPN can never be turned fully ON in this configuration and you might not be able to pulse a lot of current into the column.
A PNP transistor, on the other hand, can be easily turned fully ON(saturate) with a LOW on the PIC pin. That's why some 90% of multiplex display scheme use PNP transistors for CA column drive.
I have also noticed that you use PNP transistors to ground for CC LEDs on your designs and it too suffer the same problem as NPN in this case.