The issue is NOT whether to use the Atmega. It is already in use. The issue is that I have about 27 like products with a '51 derivative and this one was brought in with a purchase. For timing issues (48 displays of 16*160 bits every 10mS) the time critical code is in assembler. I can go on and maintain two different products, but would rather not. If no 'pin equivalent' can be found, I will redesign the board.

To the Atmega fans:
If I had 27 products with an Atmega and one with a '51, the issue would be the reverse, it is just easier to redesign one than 27.

Erik