> Would you please consider the advantages of a design in which a clean, flat > 256- or 512-byte RAM array lies ``under'' the special-function registers, > which would be accessible via the INDF0 and INDF1 indrect registers? Sounds something like the 8x51 memory mapping. This approach is nice for just about anything EXCEPT a "PIC-Basic" style application, which would require a jump-table to handle loads/stores of arbitrary function registers. This limitation would be slight, however, compared with the many advantages this approach would give: > A data-transfer loop exploiting the auto-increment features of the FSRs > could really scream, if we wouldn't have to test every iteration, ``Oops, > have we wrapped around to non-RAM addresses now?'' Not only that, but the likelihood of an errant PIC program thrashing its port pins would be greatly reduced if only instructions which are hardcoded as accessing a port could alter that port, and also allow the amount of address space dedicated to I/O to be larger (thereby eliminating the horendous amount of bank-switching that is required in some apps like open-collector emulation). > I would suggest a ``mode'' bit, in the BSR, to select compatibility in cases > where anyone still wants INDF0/1 to walk through the SFRs. Probably not a bad idea. > I have a complete paper with more details on this idea, in case anyone cares > to look at it more closely. Anyone who wants to see a PIC17CXX REALLY scream! I don't know how many layers of lawyers you would have to go through for Microchip to be able to really look at something like that. Corporations have to be very careful when accepting outside ideas, because of the risk that you might, e.g., have stolen the idea from someone else, or might have thought of something they're already doing (in which case they'd naturally not want to pay you), etc. Personally, I have some ideas I'd like to see them implement with regard to serial memory devices. But for now at least I can only dream (maybe if I won the lottery I could make the chips myself and allow Microchip to buy me out--dream dream). PS--To everyone who complained about WINMAIL.DAT--It should be **GONE, KAPUT, FINISHED, OUTA HERE, BYE BYE MS EXCHANGE! **