20 Sep
2012
20 Sep
'12
11:59 a.m.
Interesting, very interesting...
The address is on its way.
Making an EPROM module fo rthe HP9800s is one of htose things htat looks
quite easy on paper -- the only oddity is the enable signal -- but
spriisngly hard when you come ot do it. Particualrly in the HP9810/20,
where the ROM moduel backpalen is wired up on a horrble bundle of wires
which have signficatnt inductance. Decoupling well is essential, even
then it;s not as easy as it looks...
Put it is worththe effort. I noww have DataComm 1 for the HP9830, so I
cna finally make use fo the 11284 interface I have. I have C1 nd PC2 for
the HP(810, so I can get that machine talking to a serial port, etc. Alas
PC1 for the HP9820 doesn't allow the sort of low-level access I'd like,
which is why I'd like PC2...
-tony