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Re: [N8VEM-S100:1382] S-100 Bus Terminator
also, if you do a 1/3 size card, add finger pull slots in the board to
help in removal....
On Sun, Feb 10, 2013 at 8:10 AM, Tom Lafleur <laf...@lafleur.us> wrote:
> Look good for me, I will take two of them....
>
> add proto space with regulator(s) would nice, but this is fine just
> like it is...
>
> Can you make it a 1/3 size card to save cost??? not something one
> would remove very often...
>
> tom...
>
>
> On Sun, Feb 10, 2013 at 6:37 AM, Andrew Lynch <LYN...@yahoo.com> wrote:
>> Hi Paul! Thanks! I like the idea of adding the prototyping area. That
>> would be easy to do and generally useful. There is nothing wrong with being
>> frugal!
>>
>>
>>
>> My intent with kicking off the S-100 bus terminator board design is to start
>> the discussion on topic. Partially we can find out how much interest there
>> is for a bus terminator and if the concept is viable. The board is really
>> only useful for those with large legacy S-100 backplanes. We do have an
>> S-100 backplane but it is small and already includes bus termination
>> circuitry.
>>
>>
>>
>> The S-100 bus terminator design is not final by any means and meant to be a
>> starting point. I’ve made some updates to the S-100 bus terminator and
>> attached are the new schematic and PCB layout files. Please review and send
>> me any changes and/or corrections. As always, comments, questions, ideas,
>> thoughts, are always welcome! This is a home brew computing community so
>> peer to peer design and review is essential!
>>
>>
>>
>> I don’t really like the probe and bus extension concept though since we
>> already have an S-100 bus extender board which does those things and the
>> design is pretty solid. In addition, I am working with Neil to make a basic
>> boot board tool (64K SRAM, EPROM, UART, and parallel IO) called the S-100
>> 64KIO board so that’s redundant.
>>
>>
>>
>> I can send the S-100 64KIO board information to the group for review as well
>> however noting that Neil is in the process of totally redesigning the board.
>> Please keep the comments and questions more at the concept level instead of
>> the particular implementation. The design is likely going to change quite
>> significantly if I understood Neil correctly.
>>
>>
>>
>> Great commentary and questions! Please let’s discuss more. Thanks and have
>> a nice day!
>>
>> Andrew Lynch
>>
>>
>>
>> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
>> Behalf Of Paul Birkel
>> Sent: Sunday, February 10, 2013 3:38 AM
>> To: n8vem...@googlegroups.com
>> Subject: Re: [N8VEM-S100:1375] S-100 Bus Terminator
>>
>>
>>
>> Andrew:
>>
>> Being a congenital penny-pincher, as well as a "tweaker", it strikes me as a
>> lost opportunity to define a PCB like this with *lots* of unused space (and
>> yet sucking up a full S-100 slot). At a minimum, how about filling the
>> remaining space with a through-hole proto-area array? It would/could be
>> accompanied by appropriate regulators along one edge but the setup/layout
>> would be spatially similar to the buffered proto-board (replacing the
>> buffer-area with the line-clamp area). This would leave opportunities for
>> experimenters (with legacy S-100 backplanes) to wire-up small accessory
>> circuits -- else no impact on the termination function?
>>
>> Alternatively, place the bus-terminator circuitry onto the unused area of
>> the bus-extender card and get three-in-one functionality with extension,
>> termination, and probe functions. An example of this approach of combining
>> termination and extension was the VTE100a "EXTERMINATOR"; see:
>>
>> http://maben.homeip.net/static/S100/vamp/cards/VMP%20VTE%20100-A%20Terminator.pdf
>> http://maben.homeip.net/static/S100/vamp/photos/VAMP%20VTE-100%20Exterminator.jpg
>> http://maben.homeip.net/static/S100/vamp/photos/VTE%20100a%20Exterminator.gif
>>
>> If trying to go 3-in-1 ends up running into real estate issues then just
>> combine termination & extension like the VAMP.
>>
>> Another possibility would be to commit all/part of the (above) proposed
>> proto-area to specific generally-useful functions. Two possibilities would
>> be a configurable basic UART serial I/O port and/or a configurable 8 or
>> 16-bit (E)EPROM handling up to 1 MB chips. I believe that someone pointed
>> out recently that it would be useful to have a board with these sorts of
>> basic functions in order "bring-up" legacy CPU PCBs in a minimal
>> configuration. One could possibly swap one of these options for the probe
>> in a 3-in-1 configuration? Unfortunately it seems to me that when including
>> the extension-function that the resulting routing problems when adding
>> something like I/O or ROM might require a lot of accessory over-board wires
>> to effectively provide a (minimal) third connection-plane. So that might
>> not be a good idea. But the VAMP illustrates that termination+extension go
>> together quite well.
>>
>> My preference would be to leave the existing probe+extension PCB alone, and
>> instead look towards combining termination, Serial I/O, and (E)EPROM into a
>> single card. This plus legacy CPU and RAM cards would result in a
>> functional system on any "naked backplane". If some RAM could be squeezed
>> into this multi-purpose board, so much the better :->. We have all of these
>> circuits in tested-form, the only issue would seem to be routing. This sort
>> of board would also be useful to a wider audience who could only populate
>> the subsections of immediate need (e.g., not actually use the termination
>> section if employing a self-terminated backplane) -- and this would increase
>> the board-orders and therefore the likelihood that we'll quickly reach a
>> good ROI threshold.
>>
>> The bottom line for me is that a pure termination PCB seems like a lost
>> opportunity. And might not easily reach critical-mass for a board-order
>> :-<.
>>
>> On Sat, Feb 9, 2013 at 9:19 PM, Andrew Lynch <LYN...@yahoo.com> wrote:
>>
>> Hi
>>
>>
>>
>> Attached are the schematic and PCB layout files for the S-100 Bus
>> Terminator.
>>
>>
>>
>> Please review and send any changes and/or corrections to me.
>>
>>
>>
>> Thanks and have a nice day!
>>
>> Andrew Lynch
>>
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>
>
>
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> Tom Lafleur
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Tom Lafleur
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