IAP is more convenient from the hardware standpoint, but in some admittedly rare cases, for example where there isn't time to wait for the IAP to timing, the approach with the FRAM or, even the much less appealing BBRAM, is quick enough to get the job done without a multi-millisecond time window for the IAP.

I only mention this because it's the way I've most recently addressed this problem, but in the O/P's case, it does offer a fairly straightforward approach. The fact that problems exist that can actually be addressed in this way is, I suppose, purely incidental. In my particular case, I required an external memory considerably larger than what one would normally associate with 805x, and that particular size was available in FRAM. Further, since the FRAM in question was accessible in bytes AND in words, I was able to capitalize on the word access in order to make "3rd-paty" (external logic) access via DMA take some of the load off the MCU.

There are, of course, MCU's that actually have FRAM on board, so perhaps that's another approach that should be examined in order to minimize the associated pain.

Yes, IAP is a convenient feature, but there's a multi-millisecond-per-page penalty for using it. If you have to transfer multiple pages at a time INTO nonvolatile memory within a short time window, you might find yourself in this position. If you haven't got sufficient time budget to use IAP, it might as well not be available.

RE