On 12/28/13 6:54 PM, Philipp Hachtmann wrote:
> I once "tried" to count the amount of bus drivers and receivers to cover
*ALL* on the Omnibus. Lots of signals. But having an FPGA with full access would be quite
handy.
I thought some more about the form factor last night, and it occurred to me that using a
mezanine is a waste of PCB space.
You can fabricate two boards connected with one or two pair of right angle DIN-96
connectors and stiffen the joint with two
small steel flats that have been tapped for four screws that attach to the edges just
inside the card guide space.
The bars wouldn't go up far enough to interfere with the .1" connectors coming
out the side.
I got the idea from Brad's disk interface; you don't need the boards to be a
normal quad board height.
At 5 or 10 dollars a square inch from OSH Park that is a big difference in board cost. It
might even be possible to
use the same top board with different bus interface boards if I can get the signals and
power/ground pins to route so they
don't interfere. I was also thinking of trying to make all of the FPGA ins and outs to
the card unidirectional. That sort
of falls out from using DS3662's and 74vhct541's as the level shifter and bus
driver/receiver pair.
>I'd think of using a larger FPGA instead of an external ARM SoC.
This project (BitHound) makes me think something like that is something I could
understand.
http://www.bastli.ethz.ch/index.php?page=BitHoundEn