Interface Cost
6 messages · 2004-11-26 → 2004-11-27 · Yahoo Group era · View archive on archive.org
Participants: bryankvines, Jeff, Jack Boatwright, Jeff Burrell, Jarek Adamski
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. Interface Cost
Jeff · Fri, 26 Nov 2004 08:51
All;
I've assembled the bill of materials of the FPGA based expansion
interface and the total cost for a fully loaded board will be close
to $200.00. The PCB will be approximately $50.00 and all of the
parts will be an additional $150.00.
I don't know if this kind of cost will fly with very many people
for an upgrade to a TS2068. I would like to know what the minimal
attractive upgrade for a 2068 would be in terms of price and features.
My personal opinion is that any upgrade should have an IDE
interface, more memory (needed for the additional software), and
probably a serial port. A YABus connector is about $3, so it would
add little cost and provide an upgrade path for those who want more.
This could be built for less than $100. Still a bit steep, but
probably more palatable to the community.
I really need your input on this. If there is no real interest in
hardware upgrades for our little silver doorstops, then we could
simply build the more expensive expansion interface for those who
want to mess with hardware.
2. Re: [ts2068] Interface Cost
Jack Boatwright · Fri, 26 Nov 2004 07:12
I would like to see the fully-loaded board but certainly do
understand cost.
Is there a possibility of having both? I.E., start with the lower
cost board and be able to upgrade to the other? I know that this
would probably add costs but it may be a way to satisfy everyone.
My biggest concern right now is pushing forward with the "box" for
this. The info I still need is the final measurements of the
board and how tall it and all its components are so that I can
figure out how it installs and what the internals of the box
should look like.
Jack
----- Original Message -----
From: "Jeff" <[email]>
To: <[email]>
Sent: Friday, November 26, 2004 12:51 AM
Subject: [ts2068] Interface Cost
>
> All;
> I've assembled the bill of materials of the FPGA based
> expansion
> interface and the total cost for a fully loaded board will be
> close
> to $200.00. The PCB will be approximately $50.00 and all of the
> parts will be an additional $150.00.
>
> I don't know if this kind of cost will fly with very many
> people
> for an upgrade to a TS2068. I would like to know what the
> minimal
> attractive upgrade for a 2068 would be in terms of price and
> features.
>
> My personal opinion is that any upgrade should have an IDE
> interface, more memory (needed for the additional software), and
> probably a serial port. A YABus connector is about $3, so it
> would
> add little cost and provide an upgrade path for those who want
> more.
> This could be built for less than $100. Still a bit steep, but
> probably more palatable to the community.
>
> I really need your input on this. If there is no real interest
> in
> hardware upgrades for our little silver doorstops, then we could
> simply build the more expensive expansion interface for those
> who
> want to mess with hardware.
>
>
>
>
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3. Re: [ts2068] Interface Cost
Jeff Burrell · Fri, 26 Nov 2004 16:37
Jack;
Either of the boards will be about 8"X5" with the 8" dimension running parallel to the rear of the 2068. The height of the box will depend on several things. Right now I have a YABus connector on the main board with the intent of making a YABus "motherboard" available. The motherboard will sit near the TS case and project into the "Z" direction (toward the ceiling, so to speak) about 8 or so inches.
As to the cost of the boards. It would be easier to simply build the fully-loaded board or the simpler board (or possibly both). Unfortunately, upgrading isn't all that easy and would actually add cost and complexity to the board for no major advantage. I understand that most of us who play with the 2068 are probably getting on in years (I won't see 50 again), so the cost of a $200 board will be disposable "fun money" and not too big a burden. The vibe I've picked up here, though, is that there are several (many) people for whom $200 is too much of a hurdle.
Without going into too many technical details, using FPGAs - especially with a 48MHz clock as this design does, pretty much demands using power planes rather that routing power around the PCB. While the cost of multilayer boards isn't prohibitive (I routinely specifiy and design 8 to 12 layer boards where I work) they are a significant bump in cost. For example, an 8X5 2 layer board is about $13 where a 4 layer board of the same size comes in at about $30 (both in low volumes). Also, the complexity of the design affects the cost. Another wrinkle is that the most cost-effective chips nowadays use 3.3V or lower supply voltages. While they can be made to work well with the 2068, it does add some complexity to the design and tends to put a floor on the cost of the expansion.
Another irony about this project is that starting from a clean slate, you could do a complete 2068 clone, including VGA output, faster Z80 processor, more memory, etc. for about the same cost. In any case, it seems a bit much to marry a $250 expansion interface onto a $60 computer, especially when the computer will be the processing bottle neck. I am definitely up for inflicting excessive technology to solve simple problems (I AM and engineer after all), and if that is the purpose, I'd say let's go for the gusto. If, on the other hand, the purpose of the project is to do a cost effective upgrade to the 2068 to address its deficiencies and allow it to use modern peripherals (better mass storage is an obvious example), then a simpler interface using a CPLD (lower density and lower cost logic device) would be the way to go.
One other reason I'm looking at a simpler interface has to do with my time. My job swings between being insanely busy and just too busy. Right about now it is swinging into the insane area as we are starting a complete re-architecting of our electronics suite. Our company is in the process of being acquired and I don't know what kind of stressor that will be nor what other demands there will be on my time. Also, I have just gone through a period of about 4 months where I my health was not too good and it was all I could do to keep up with the rent-paying job. I don't know if anyone else in the community has the ability to help with the hardware development and if not, I would like to launch something that would not take a great deal of my time to develop. There will be a large amount of work needed just to get the FPGA version up and operating in a minimal mode much less with the bells and whistles we would like to see. To be frank, I don't know if I'll have the time to get
that amount of work done any time in the next 6 months to a year. I'd hate to launch something that was a disappointment and had people feeling they weren't getting what they paid for.
The above only addresses the hardware portion. All of the software to support the new functionality will be just as big a job. All of this blathering is designed to let you and everyone else know why the design is going so slowly and also give some insight to the questions and problems with which I have been wrestling.
Jack Boatwright <[email]> wrote:
I would like to see the fully-loaded board but certainly do
understand cost.
Is there a possibility of having both? I.E., start with the lower
cost board and be able to upgrade to the other? I know that this
would probably add costs but it may be a way to satisfy everyone.
My biggest concern right now is pushing forward with the "box" for
this. The info I still need is the final measurements of the
board and how tall it and all its components are so that I can
figure out how it installs and what the internals of the box
should look like.
Jack
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4. Re: Interface Cost
bryankvines · Sat, 27 Nov 2004 05:41
Hi Jeff,
I could probably swing the money for one of the boards - but would this be something I
would have to assemble myself or would this be something that would be already
assembled? I'm assuming most of the components that will populate the board are going
to be of the surface-mount variety.
On the other hand, I've been thinking... What would be involved in building an expansion
box that replicated the 64-pin expansion connector as a series of slots -- maybe 8 of
them -- along with a power supply to provide power. Maybe a place to physically install a
3.5" floppy drive or two? Make it 10" deep, 17.5" wide and 3.75" tall. Sheet metal, bent to
form a box. One piece is the front/bottom/rear, the other piece is the top and sides. Sort
of like a VCR box. Put two screws on each side to hold it together, and maybe a metal
support inside so it will bear the weight of a monitor. The front bezel could be plastic, so
ti wouldn't look so utilitarian.
The 2068 snaps into the front like the it would have with the original Timex expansion
box. Provide a power connection to the 2068, and maybe a pass-through for modulated
video (does anyone use this port anymore?). Cassette I/O, audio, and composite video are
available on the edge connector and thus are already inside the expansion box for output
on the back.
With 8 slots, and a maximum expansion card size of 3" x 8", you could put pretty much
any sort of functionality you wanted into it.
The slots would be female 64-pin card edge connectors, the same type you generally see
on full-width 2068 add-ons. So the card design would be fairly simple - think Apple ][
expansion cards. Plus, I think that with a pair of female 64-pin card edge connectors
back-to-back, any single expansion card could be plugged directly into the rear of a
2068, either for prototyping the card or mounting in its own box.
I'm working on a few drawings... It probably won't amount to much, but oh well. It's a long
weekend, and I really don't want to put up the Christmas lights yet...
--
Bryan Vines
--- In [email], "Jeff" <jburrell7@y...> wrote:
>
> All;
> I've assembled the bill of materials of the FPGA based expansion
> interface and the total cost for a fully loaded board will be close
> to $200.00. The PCB will be approximately $50.00 and all of the
> parts will be an additional $150.00.
>
> I don't know if this kind of cost will fly with very many people
> for an upgrade to a TS2068. I would like to know what the minimal
> attractive upgrade for a 2068 would be in terms of price and features.
>
> My personal opinion is that any upgrade should have an IDE
> interface, more memory (needed for the additional software), and
> probably a serial port. A YABus connector is about $3, so it would
> add little cost and provide an upgrade path for those who want more.
> This could be built for less than $100. Still a bit steep, but
> probably more palatable to the community.
>
> I really need your input on this. If there is no real interest in
> hardware upgrades for our little silver doorstops, then we could
> simply build the more expensive expansion interface for those who
> want to mess with hardware.
5. Re: [ts2068] Interface Cost
Jarek Adamski · Sat, 27 Nov 2004 12:32
Cytowanie bryankvines <[email]>:
> Please see (...) in the files area, and let me know what
> you think.
Bryan, they are very nice. However it would be very
expensive to make such thing.
I've designed the YAMOD (YABUS modules) to make universal
I/O interfaces, available for wide range of computers.
Thanks to this, I can produce not 3-5, but 20 boards. And
because I used one-side coppered laminate, they can be
build for $10 per piece.
Edge connectors need both-sides coppered laminate. Such
4" x 3" board with coppered holes costs from $15 (with
no elements). It makes only sense to make such slots for
ISA cards, which were produced 8-12 years ago and now are
very cheap (from $2).
Now I have modules for IDE devices and AY-3-8910 (the ZX128
port compatibility and 16 I/O lines in LPT like slot could
be interested to TS users). However, I still wait for the
DIN slots that sail from Asia.
Next year YAMOD for 1.44 FDD should be ready - based on
the WD37C65 chip would give good possibilities (PC AT
compatibile, except the DMA transfer.)
Well, I was thinking several years, how to make cheap and
useful extensions - the YABUS originates from 1997 year.
But that time I wasn't able to spread the idea...
--
Jarek Adamski
ul.Sobieskiego 10A/5
99-200 Poddębice
Poland
tel. +48603445345, +48436782892
mailto:[email]
Do you wish to upgrade an 8bit computer?
See 8bit.yarek.pl and contact me.
6. Re: Interface Cost
bryankvines · Sat, 27 Nov 2004 08:04
I'm really sleepy. I added three PDFs of some drawings I just finished up.
Please see
- BKV TS Expansion Box Front.pdf
- BKV 2068 Expansion Box.pdf
- BKV 2068 Expansion Card.pdf
in the files area, and let me know what you think.
To cut down on board size, the RGB, Audio, and Cassette I/O outputs
could be put on a short card behind the floppy drive. That would shave
several square inches off the board.
--- Earlier, I wrote:
> I'm working on a few drawings... It probably won't amount to much,
> but oh well. It's a long weekend, and I really don't want to put up
> the Christmas lights yet...
--
Bryan Vines