Quote Originally Posted by Ron Marcus View Post
I guess this is a bit of a gripe, but maybe there is a legit answer to this question. I seem to be working with more and more pins on a single processor these days. Why do they split some of the ports? Fer instance, on the 18F4520 in the TQFP, ports C and D are split right down the middle. Is there a legit reason for this, or more convenient in the die fabrication?
Ron
Ever noticed how you can ALMOST put a 28 pin DIP PIC into a 40 pin DIP PIC socket? Or for that matter, you could (again ALMOST) put an 18 pin PIC into a 40 pin PIC socket.
Same thing for the TQFP. With the 18F672x (64pin TQFP) and the 18F872x (80pin TQFP), everything is in the same place except for the 16 corners pins. I used that to make my 64/80 TQFP adapter board, which has a 40 pin IDC ribbon cable header to plug a 672x/872x into a socket previously occupied by 877, 452, and a 4620, but with loads more memory. And I use another header holding the rest of the pins to run another PCB.