23 May
2000
23 May
'00
7:06 p.m.
ard(a)p850ug1.demon.co.uk (Tony Duell) wrote:
Now that's interesting. When I got my (second-hand) Intellec MCS8i, it
didn't work. One of the faults was soon traced to an 8205 chip on (IIRC)
one of the memory boards.
At the time I'd never heard of this device (and didn't have a suitable
Intel databook), but from the schematics in the manual it appeared to
have the same pinout as an 74LS138. So I stuck one of those in and of
course it worked fine (and still works AFAIK).
I wondered at the time what the difference was between an 8205 and a
74LS138. Now I know...
-tony
Hi Tony
As I recall, the difference was that the Intel parts could
stand a much lower negative voltage ( -10V? ) than the general purpose
TTL. This made is compatible with the 8080's. Also, as
I recall, the 8205 were also Schottky's.
Dwight