[fowlerm]

The two PICs in the RC are 18F8520 80-pin devices The Microchip C18 compiler can build for the 452's so the code that does your calculation shouldn't have to be rewritten (if it's in C). You will need to create a new project in MPLAB from scratch and use a linker file for the 452 instead of the 8520. There is no need to include RC specific code in your new project, but you may want to look at ifi_aliases.h and ifi_picdefs.h to get an idea of how to define aliases for the hardware registers. Keep in mind that the 452 doesn't have all of the hardware that the 8520 has, so you may want to look at the 452's spec sheet to make sure you haven't aliased a register that doesn't exist. You can reuse some of the IFI code, like the serial driver, this may save you some time in getting you project up and running.