>
>
> On Wednesday, March 08, 2017 06:11 AM, Neal Pisenti via ARTIQ wrote:
> > * For ARTIQ core device, we would ideally jump straight to using a
> > Kasli, but as that isn't likely to be done in the next few months, I was
> > planning to use a KC705 as the core.
>
> The "EEM" DDS/synth Kasli extensions may not necessarily be ready before
> Kasli. So I don't see how the KC705 helps - is it because you want more
> extensions that one Kasli would support? Supporting this KC705 scheme is
> more gateware development and one more configuration that needs to be
> documented, packaged and maintained. Maintainance means that we need to
> check regularly (preferably automatically) that it keeps working when we
> modify ARTIQ and fix any bugs that pop up. It takes work.
>
Valid point -- my main thought with this setup is exactly what Tom
articulated; the KC705 -> VHDCI is a stopgap until Metlino/Kasli
development is completed. And it would allow us to start using digital IO
immediately via the PCB_3U_BNC EEM, and we might spin up some in-house
boards for multichannel DAC over SPI. We shouldn't need the DDS/synth
modules for some time still, since all of our DDS currently exist as "slow
peripherals" in the artiq sense.
The other short-term alternative I see is adapting either the nist_clock or
nist_qc2 builds, and making our own FMC -> ___ breakout. But piggybacking
on the EEM architecture seems cleaner and more future-proof. When the Kasli
is done, we would either abandon the KC705 for a Kasli as core, or
(depending on the cost) plan for 1x Kasli as DRTIO connected to the KC705
SFP. That would certainly put a limit on how many things we can control,
but will probably satisfy our needs in the foreseeable future.
Even though the uTCA/Metlino setup will be exceedingly nice, for neutral
atom experiments it is currently overkill. But whether the upfront cost of
a uTCA chassis & associated hardware is worth additional development
headache to exclusively use Kasli baords...? Remains to be seen.
> * KC705 has 2x FMC headers, which would drive 1x VHDCI carrier card,
> > providing 8x IDC for EEMs. We would buy FMC -> VHDCI adapters for this
> > interconnect.
>
> What adapters in particular? http://www.ohwr.org/projects/fmc-vhdci? We
> didn't check compatibility of any of those.
>
When I chatted with Joe, we looked at this one:
http://www.ohwr.org/projects/fmc-dio-32chlvdsa/wiki/Wiki
@Greg -- are the board files available for this? I looked on the Creotech
website but couldn't find it for sale anywhere (which is odd, because I
swear I saw it there before, for ~ $500). Even so, I wonder about pricing
it out at MacroFab or one of these other small-turn PCB companies before
spending $1k on a pair of them.
Cheers,
Neal
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