> FYI, Till has designed a breakout board from FMC directly to the DDSs (i.e., > no > cable in between, so the DDSs are collocated with the FPGA). We're using it > in our zynq system, and it may be an easy way to get an artiq test system up > and running.
I checked out these boards yesterday and I think they would work quite well as a solution for most people, without requiring recourse to a distributed RTIO system. Each breakout board fits on an LPC FMC and holds 11 DDS daughterboards and provides 28 galvanically-isolated TTLs, 21 outputs and 7 inputs (it is possible to trade inputs for more outputs when building by choosing a different, pin-compatible isolator/level shifter chip). With the KC705 and its two FMC connectors, this would mean 22 DDS channels, 42 TTL outputs, and 14 TTL inputs. The pinout of the FMC is identical between the Zynq board and the KC705 (since it complies with FMC spec), so it's plug and play in that respect (although obviously the pinout needs to be coded appropriately in the FPGA). And since Till has already done the design work, very little effort is needed to implement. The only requirement is that we would need to build a box to hold the FPGA, DDSs, and TTLs and break them out to connectors on the f ront panel, which is not very onerous. For those interested, in principle more DDS slots or TTLs could be added to each board with some minor tweaking, and I will work on this once I get the files from Till. The boards are designed to use either the new AD9914 DDS daughterboards Till has designed for the clock folks or the old AD9858 DDS daughterboards that Quantum I/Quantum II/Penning have been using. All of this is not to say that we cannot/should not pursue the distributed RTIO idea, which in the end gives more scalability, but I think at least for the immediate needs of just about everyone in the group, one or two of these FMC breakout boards would suffice, and they have the advantage of already existing and having been tested. I will try to get some made in time for Sebastien's visit, but we can plan on using the Papilio Pro if they aren't ready yet. Daniel _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
