[Coco] 8 slot multi pak

John W. Linville linville at tuxdriver.com
Thu Jan 19 09:21:06 EST 2017


Did you work for Chuck-E-Cheese???

On Wed, Jan 18, 2017 at 01:32:28AM -0600, Dave Philipsen wrote:
> Yes, that's possible.  I have some old passive backplanes that were used for
> an animatronics system that used a 6502 processor at 1 MHz as the main board
> and the CPU card with just a single set of buffers would run 8 or 9 other
> cards on the backplane.  The backplane fit into a 19" rack and I don't
> believe there was any kind of termination on the end.  Literally hundreds of
> these card cages were made and used about 12 hours a day, 365 days a year
> and some are still running today (since 1977) and have had no problems in
> that regard.  Some expansion cards had 6821s, some had 6850s, that sort of
> thing.  The backplane PCB was double thickness - .125".
> 
> Dave
> 
> 
> On 1/18/2017 1:18 AM, RETRO Innovations wrote:
> > On 1/18/2017 12:44 AM, Dave Philipsen wrote:
> > > I think you could probably drive 8 slots with a single set of
> > > buffers.  Just make sure the buffers have a high fanout.  I think
> > > some buffers can do 20 or more TTL loads on fanout.  And you might
> > > also want to experiment with termination on the end of the lines.
> > I meant to also note that the capacitance might be an issue, but forgot
> > to add that before sending.  TI and S-100 bus machine shave 8-12 slots,
> > but most include buffers on each card to deal with the issue.
> > 
> > Jim
> > 
> > 
> 
> 
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-- 
John W. Linville		Someday the world will need a hero, and you
linville at tuxdriver.com			might be all we have.  Be ready.


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