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Re: [N8VEM-S100:1382] S-100 Bus Terminator
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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