I am working with an OSD module which displays GPS info in a video stream. It uses a 16F819 and is being clocked externally at about 28 MHz. Since this is outside of spec for this chip (it has worked fine on a dozen chips so far), I'd like to upgrade to a 18F1320. Here's the problem...It's written in assembly, and uses some bank switching and table lookups with indirect addressing. In looking over the 18F manual, it is confusing where the physical start of the RAM is, and what type of bank switching, if any, will be necessary. Has anyone re written a 16F ML program for a 18F series and what will I need to look out for?

Thanks,
Ron