PIC18F4550 to 18F4553 Comm Issue?

[Demon]

http://www.microchip.com/wwwproducts/en/PIC18F4553

At quick glance, they both use the same pins for EUSART, so that's a good thing.

Check out this funky register on the 4553: DEVID1. EDIT: never mind, The Device ID registers are “read-only” registers

Don't look for more pages in a 4553 datasheet, there are none:

This document is supplemented by the “PIC18F2455/2550/4455/4550 Data Sheet”

It is compatible with the 4550, so you're missing something very small if you already have it working between two 4550.

Hmm, very dumb question: have you changed the model when you compile?

Robert