HP82143 Processor details

[blackjetrock]

(09-25-2023 03:15 PM)brouhaha Wrote:  If the difference at the end is only in the bytes from addresses 0xfc0 through0xfff, it could be that your boric chip, his, or both, are actually MK3870/n2 chips, in which those addresses are extra RAM rather than ROM. The RAM is NOT mirrored at lower addresses on e.g. the MK3870/22.

That is an interesting idea. I have written some code and run it on both ICs and it looks like the top few bytes are ROM, as I can't change the value stored there. That's assuming that the code I wrote is correct, it's small and simple so I'd think it was OK. So I still don't know what those values are or why they are different to Sean's file.

Andrew