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Use 16f877a open as an old Z80

PostPosted: Sat Oct 21, 2017 5:01 pm
by ErBo
Hi,
In 2008 very good experiences with 16f877a in JAL-language from Bert van Dam's book and his Wisp648 programmer via ser port and all kinds of returns on PC-terminal and pin out-in-puts.
No big problems, even am not good with math, could code simple with good results.
But,
in 1980 the Tandy TRS80 Z80 1MHz 16K RAM was totally open: poke via simple BASIC into any addresses in RAM or SCREEN or even in no connected addresses to catch bytes on the motherboard-connector. Never had such clear open thing since!
So,
what odds using 16f887a same way???
Theoretically:
from PC via Velleman interface K8055N to some 74hct595 ser-in par-out to reach to any address from the 16f877a in icsp and/or parrallel without JAL or C or MATLAB or anything?
1. - - Probably needs faster interface?
Dont know anything about the timing and the kind of signals needed to write or read addresses from and to the 16f877a.
2. - - Has someone done this before? (who ?)
3. - - Where to find info about all the programming signals?
4. - - Is this a known issue with a name?
( hope do same thing in AVR )
Thanks,
ErBo.