Q-bus I/O project

Toby Thain toby at telegraphics.com.au
Sat Oct 10 19:50:17 CDT 2015

On 2015-10-10 2:10 PM, David Bridgham wrote:
> Wow.  A pretty board indeed.  Thanks for showing it off.  This is also
> interesting to me since  a friend and I have been talking about building
> something rather similar (and entirely different at the same time, we're
> just focusing on the mass storage function and using an FPGA).  I'm

^^ A popular idea. I've been kicking around the same idea with friends 
for 10 years now. :(

Need to find time...


> curious about some things though, if you'd be willing.
> Bus drivers (along with voltage level conversion) have been a problem.
> You seem to be using 74LVC parts.  Are they close enough?  Though I also
> see a bunch of FETs down there.
> I've used OSHPark in the past for small boards but for 45 sq.in. boards
> they'd seem to be awfully expensive, even if using their medium run
> pricing.  The fingers look gold plated.  It could be just the ENIG
> finish but I also see little tails running off the bottom as if you're
> setup for hard gold plating.  Does OSHPark have that capability?
> I gotta say that I'm impressed with your soldering skill as well as
> stamina.  I was going to ask if it was machine assembled but I see in a
> later message that it wasn't.  I was hoping for the Pick 'n' Paste
> machine to come along and save me from having to do all that by hand but
> that project seems to have faded away.
> I'm curious why you didn't use resistor networks instead of discrete
> components.
> I also love that your design tool put omegas on the silk screen for the
> resistor values.
>   -Dave

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