5 Dec
2014
5 Dec
'14
12:12 p.m.
-----Oorspronkelijk bericht-----
Van: cctalk [mailto:cctalk-bounces at classiccmp.org] Namens tony duell
Verzonden: vrijdag 5 december 2014 19:26
Aan: General Discussion: On-Topic and Off-Topic Posts
Onderwerp: RE: HP9830 memory / was Re: Still looking for Infotek MX-30 RAM
that
takes
> I assume you're jsut going to be
plugging into the HP9830 I/O slot
Yes. I'm considering putting the mass storage
ROM on the I/O slot card
also (similarly to how the sector buffer works), but since that ROM is
hard-addressed, that won't actually free up the ROM slot it would
normally occupy.
I don't really see the point. It's fairly easy to make a ROM cartridge EPROMS (IIRC 2 EPROMs, a 74x00 and a couple of
transistors (to convert the
12V selects back to 5V). Such a board (hand wired) was shown at HPCC a
couple
of years ago.
If you do make your own Mass Memory ROM module, figure out a way to have
a switch to disable it. The Mass Memory ROM intercepts all sorts of BASIC
commands, to the extent that DISP and PRINT (at least) fail unless there
is a
working disk drive connected too. Continually plugging
and unplugging the
ROM
is hard on the connectors (yes, you can still get
them, but desoldering
the old
one is a pain).
Incidentally, the ROM module connector on the 9830 (but not on the smaller
machines) is 0.125" pitch, double sides, 18 pins on each side. Now where
have
you seen that before :-). It made finding an extender
board very easy when
I was
fiddling in that area.
-tony=
For who is interested, I'm busy designing a replacement rom board so failing
boards can be replaced ( I know at least 3 9830 with failing rom's)
I'm ready with the artwork of the connector fingers 2x10 and 2x25
(Ultiboard), if any one wants a copy of those drop me a line offlist.
The board will support 27C64 to 27C256 eproms, at first when the board is
ready I'll order a prototype serie.
-Rik