4 Sep
2001
4 Sep
'01
12:46 p.m.
Rumor has it that David Woyciesjes may have mentioned these words:
It sounds like you would get more enjoyment out of
building & using
it, rather that letting it sit and collect dust. If you're toying with
building it, I would say go for it, but keep all the packing and paperwork,
too. That helps increase the 'value'.
I think it all depends on whether you plan on selling it, or keeping it. I
would definitely build & use it.
[snippage, fore and aft...]
I don't necessarily disagree with you, but the "reproducability" would be
decreased once the kit is built... i.e. you can't [easily] scan the boards,
or re-design them in AutoCad, etc...
With this in mind, I was digging thru an old box of CoCo stuff I have and I
came across (2) Xpndr1 expansion cards, 1 of which is virgin. A quick
search of Google shows nothing about them...
I've started re-designing the card in AutoCad (as if I didn't have *enough*
projects ;-) with improvements. Some are minor, like putting the signal
names on the top of the card instead of the bottom (so it's easier to see
the signal names when I attach a small breadboard to the top of the
card...) some are major (or going to be) like the extra room for standoffs
so it'll be self-supporting, and also connector ports for both a "PC hard
drive power port" and a "PC floppy drive power port" so you can power the
thing from any PC power supply *or* an FD-50x power supply. I also plan on
having one that buffers all of the data, address & major signal lines on
the board, so that experimenting might be easier without blowing the entire
CoCo bus.
Which leads to my questions:
A) Anybody know anything about the company that marketed these, as I don't
want to intentionally break any copyright laws; but with no info on the
internet & the extreme possibility of the company no longer existing, does
anyone think I'll be in trouble with the law WRT copyright laws? I'm mainly
just using the original as a pattern for (1) the signal names & pinouts,
and (2) the dimensions of the connectors & pins (I didn't have anything
else that had the ground pegs on either side of the connector).
B) I can prolly find this out for myself, but there are many others here
better than me on the hardware side of things: What would be some of the
better [a.k.a more useful] buffer chips I could use to buffer the address &
data busses?
C) Are there any *real* problems with powering the card from a separate
power supply? I'm assuming I need to tie the grounds together, but I
wouldn't want the +5 / +12 / -12 volt rails tied at all -- they should be
separate, right? [[no, I really don't feel like dissecting my MPI just
yet... altho I think it's the *only* piece of computer equipment I've never
taken apart! ]]
Should I check the voltage levels of the power supply & the CoCo to see
how close they are, or as long as they're both within TTL levels is it OK?
I'm mainly worried about the PC supply being of a higher voltage than the
CoCo, if that'll cause problems.
=-=-=-=-
The designs (when they get closer to completion) I will have on my website
for free, but if I make several cards and someone else is dumb^H^H^H^H bold
enough to purchase one I would sell them for a small profit...
Anywho, thanks for listening, and double-thanks for any advice that others
might be willing to offer... ;-)
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger --- sysadmin, Iceberg Computers
Recycling is good, right??? Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.
4 Sep
4 Sep
1:11 p.m.
If you take the time to redesign this device, the simplest, lowest-risk,
easiest, cheapest, and least-exposed-to-copyright-infringement will be to
redesign the entire thing in a single CPLD or FPGA, on a board that matches
physically and logically, but in no way infringes on the copyright associated
with the artwork, which is what can be copyrighted. Circuits themselves would
have to be patented, and, folks have found, that's a waste of time, since
generating a logical equivalent circumvents the patent, though not the PCB
copyright.
Once you have a prototype of your new replacement working, put the original on
eBay and take a vacation with the proceeds. ... or don't ...
Dick
----- Original Message -----
From: "Roger Merchberger" <zmerch(a)30below.com>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, September 04, 2001 3:46 PM
Subject: CoCo Xpndr1 (was: RE: Keep or assemble???
Rumor has it that David Woyciesjes may have mentioned
these words:
It sounds like you would get more enjoyment out
of building & using
it, rather that letting it sit and collect dust. If you're toying with
building it, I would say go for it, but keep all the packing and paperwork,
too. That helps increase the 'value'.
I think it all depends on whether you plan on selling it, or keeping it. I
would definitely build & use it.
[snippage, fore and aft...]
I don't necessarily disagree with you, but the "reproducability" would be
decreased once the kit is built... i.e. you can't [easily] scan the boards,
or re-design them in AutoCad, etc...
With this in mind, I was digging thru an old box of CoCo stuff I have and I
came across (2) Xpndr1 expansion cards, 1 of which is virgin. A quick
search of Google shows nothing about them...
I've started re-designing the card in AutoCad (as if I didn't have *enough*
projects ;-) with improvements. Some are minor, like putting the signal
names on the top of the card instead of the bottom (so it's easier to see
the signal names when I attach a small breadboard to the top of the
card...) some are major (or going to be) like the extra room for standoffs
so it'll be self-supporting, and also connector ports for both a "PC hard
drive power port" and a "PC floppy drive power port" so you can power the
thing from any PC power supply *or* an FD-50x power supply. I also plan on
having one that buffers all of the data, address & major signal lines on
the board, so that experimenting might be easier without blowing the entire
CoCo bus.
Which leads to my questions:
A) Anybody know anything about the company that marketed these, as I don't
want to intentionally break any copyright laws; but with no info on the
internet & the extreme possibility of the company no longer existing, does
anyone think I'll be in trouble with the law WRT copyright laws? I'm mainly
just using the original as a pattern for (1) the signal names & pinouts,
and (2) the dimensions of the connectors & pins (I didn't have anything
else that had the ground pegs on either side of the connector).
B) I can prolly find this out for myself, but there are many others here
better than me on the hardware side of things: What would be some of the
better [a.k.a more useful] buffer chips I could use to buffer the address &
data busses?
C) Are there any *real* problems with powering the card from a separate
power supply? I'm assuming I need to tie the grounds together, but I
wouldn't want the +5 / +12 / -12 volt rails tied at all -- they should be
separate, right? [[no, I really don't feel like dissecting my MPI just
yet... altho I think it's the *only* piece of computer equipment I've never
taken apart! ]]
Should I check the voltage levels of the power supply & the CoCo to see
how close they are, or as long as they're both within TTL levels is it OK?
I'm mainly worried about the PC supply being of a higher voltage than the
CoCo, if that'll cause problems.
=-=-=-=-
The designs (when they get closer to completion) I will have on my website
for free, but if I make several cards and someone else is dumb^H^H^H^H bold
enough to purchase one I would sell them for a small profit...
Anywho, thanks for listening, and double-thanks for any advice that others
might be willing to offer... ;-)
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger --- sysadmin, Iceberg Computers
Recycling is good, right??? Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.
1:53 p.m.
If you take the time to redesign this device, the
simplest, lowest-risk,
easiest, cheapest, and least-exposed-to-copyright-infringement will be to
redesign the entire thing in a single CPLD or FPGA, on a board that matches
physically and logically, but in no way infringes on the copyright associated
with the artwork, which is what can be copyrighted. Circuits themselves would
have to be patented, and, folks have found, that's a waste of time, since
generating a logical equivalent circumvents the patent, though not the PCB
copyright.
That's basically what Michael Holley did with his new floppy
controller for the SS-30 bus machines from SWTPc. It's compatible
with the SWTPc DC-4 but is implemented in a CPLD. It also adds
support for a few things the original couldn't do.
Jeff
--
Home of the TRS-80 Model 2000 FAQ File
http://www.cchaven.com
http://www.geocities.com/siliconvalley/lakes/6757
2:58 p.m.
Rumor has it that Richard Erlacher may have mentioned these words:
If you take the time to redesign this device, the
simplest, lowest-risk,
easiest, cheapest, and least-exposed-to-copyright-infringement will be to
redesign the entire thing in a single CPLD or FPGA, on a board that matches
physically and logically, but in no way infringes on the copyright associated
with the artwork, which is what can be copyrighted. Circuits themselves
would
have to be patented, and, folks have found, that's
a waste of time, since
generating a logical equivalent circumvents the patent, though not the PCB
copyright.
Thanks for the good info (as that will help me with other projects) but in
this particular case, it's just a bare board. As I don't have a scanner
hooked up, and my digipixelator is broked :-( I currently cannot easily
share a picture of the board with y'all. But... it's just a board. All it's
designed to do is to bring the CoCo bus signals to pads in which the end
user could solder wires to to interface chips (which you add yourself) to
implement in designing your own expansion(s).
Oh, and it had extra +5V & Gnd rails in between the IC pin rows, to make it
easier to hook up Vcc & ground to your chips. If you wanted +/- 12V, you
had to route that yourself... (and which was no longer supplied by the
CoCo2/3)
I'm just using the board as a template to design my own board, that *will*
have buffer circuits, a separate power supply junction, & other things
(like maybe a breadboard) before I put it into initial use.
And I'd love to *find* a used/older/cheap CPLD programmer... <g>
Once you have a prototype of your new replacement
working, put the
original on
eBay and take a vacation with the proceeds. ... or
don't ...
Erm..... Nope. ;-)
Dick
=-=-=-=-=-=-=
And Chris wrote:
This is where you can get in trouble. If you make your
mods available to
the public (even if for free), you can be seen as infringing upon the
owners rights. However, if the company has gone out of business, you
probably wont get in any trouble. But do NOT confuse out of business with
public domain, they are not one in the same, just because the company is
out of business or isn't selling the item any more, does NOT mean that
the item is public domain. They still have the rights to it, and can
choose how and where it can be made available. I personally still don't
think you will have a problem, but you will most likely technically be
breaking the law.
I do understand that... but with my redesign (which is basically from
scratch, as I *could* find all of the info from other sources) my board
will be so much different from what actually sits in front of me, I don't
think it would be recognizible whatsoever to the original board [[ bad
mental picture: imagine a calico cat laying an egg & hatching an
alligator... eeewww! ]]
All I used the board for was the external measurements (which my old
drafting scale worked wonderfully) and the pin signals (which I could
easily have gotten from my CoCo 1/2/3 techref manuals... if they weren't
boxed & stored).
From there, it was all AutoCad & my Imanganation.
Thanks for the help!
Roger "Merch" Merchberger
--
Roger "Merch" Merchberger --- sysadmin, Iceberg Computers
Recycling is good, right??? Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.
8334
days inactive
8334
days old
3 comments
3 participants
participants (3)
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edick＠idcomm.com -
jhellige＠earthlink.net -
zmerch＠30below.com