5 Sep
2018
5 Sep
'18
8:27 a.m.
On Tue, Sep 4, 2018 at 10:00 AM, Al Kossow via cctalk
<cctalk at classiccmp.org> wrote:
We have two in the CHM collection. This is the first
time I've ever seen one
work. I was thinking it might be fun to try to get FORTH running on it.
That sounds cool.
I may also mod mine so that it puts out proper RS-232
levels with a
piggyback board on the 1988. They just power it with +5v, which doesn't
work at all talking to my Mac. An old Wyse-75 wasn't so fussy.
Hmm... I hadn't noticed that. Glad you pointed it out. I've had
problems in the past with other machines and low-voltages on RS-232.
If you look at the schematic, they did some pretty
weird things, like
using a 2758 for address decoding, and then there's the floppy disk
interface.. No error checking?
I found that surprising - floppies are hardly reliable enough to
forego error checking.
1980 seems really late to be trying to build a system
like this.
Agreed.
It looks like a design OSI would have come up with.
That was my thought when I saw the 6852. It was either because of OSI
or they saw an app note somewhere and decided not to use a WD 177x
chip.
-ethan