With this talk of CC and CA displays, I'd like to share a technique I've used and found very useful.

I like to design PCBs that would work with CA as well as CC displays; the only hardware difference between the two is whether to tie the emitters of the driver transistors to +5 or ground, depending on the display.

So, provide for a jumper that lets you select between the two.

AND, use this signal as an input to the PIC to tell it what kind of display is being used. Keep 2 lookup tables in the code, one for CA and the other for CC; depending on the state of the jumpered signal, the code uses the corresponding lookup.

During production time, then, it becomes easier as one could use either CA or CC, without having to change the code; just connect the common line to +5 or Gnd, and it will work.

Regards,

Anand