--- In "Don W. Carr" <> wrote:
>
> For me, the best thing you could add is two high speed counters,
and extra
> serial ports. I have a project that needs 5 serial ports, 2 high
speed
> counters, and some DIO, and this little board would be perfect if
we could
> do that. By the way, we really like the way you count transitions
instead of
> cycles since that cuts the error for frequency calculations in
half! We
> would even be willing to pay for the mods.
Could you elaborate on the high speed counters? Do you mean a free-
running register in memory space counting upwards or a frequency
counter watching a DIO pin?
With a custom FPGA, we can strip down features you tell us you don't
need and make some more room for things you do. I'm not sure I can
fit 3 extra UARTs, SD card core, NAND controller core, boilerplate
glue logic and frequency counters all in a 570 LUT CPLD/FPGA, but if
you're willing to give up SD and boot to NAND flash it would be no
problem.
>
> I like the XDIO, but I think it would be better if you could still
use the
> other DIO when the counters are used, and also you need a longer
register
> for the PWM high/low times so we can hit all frequencies +/-0.05%
duty
> cycle.
By counters do you mean the little "trick" you can do to loopback PWM
to the pulse-counter for an arbitrary freq free-running counter?
This indeed will tie up the PWM pin and feature and the pulse timer
feature, but other GPIO's and features should still be useable.
>
> When will you have a case? We would like room for a signal
conditioning
> board in the case like you have with your other cases.
This board is a standard size that fits into some very inexpensive
off-the-shelf extruded aluminum cases. We only have to do custom
metal and screening work on the endplates and they should be here
this week. I'm not sure theres room in the smallest case we're
supporting for a "daughterboard" with a mating 40 pin female
connector. What would work though would be to just solder your board
to the .1" headers directly. This would get you an extremely rugged
device with a very low stack height.
We used the .1" headers partially for the reason that they would be
easy to solder a daughterboard directly to. We were thinking about
doing an edge connector like a SIMM socket or a high density hirose
style connector, but came to the conclusion that would just be
idiotic for targetting ruggedness. Edge connectors are mechanically
weak and unwieldy (there was a reason PC/104 went the way it did
rather than stay with the PC card-edge slots). Those high-density
connectors aren't much better and some were only rated for 50 mate
cycles! Granted they'd likely only be mated once, but that just
doesn't sound like a reliable connector to me, so instead we put
the .1" pin header on and tons of mounting holes.
We really like these extruded aluminum enclosures. An advantage
besides being inexpensive is that they are extremely strong-- you
could probably run one of these things over with a truck without it
collapsing! We will definitely be testing that once they come in.
P.S.
Our production workers say you stopped by our office a month or so
ago to pick up some boards-- wish you would have dropped by in Bob's
or my office before you left, as we would have liked to have met you!
//Jesse Off
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