I second Tom's thoughts here -- I would go for the largest Artix-7 we can reasonably accommodate, just for flexibility. Going with the -2 speed grade sounds like it makes a lot of sense.
Best, Daniel ________________________________ From: ARTIQ <[email protected]> on behalf of Thomas Harty via ARTIQ <[email protected]> Sent: Thursday, June 29, 2017 4:16:32 AM To: [email protected] Subject: Re: [ARTIQ] ARTIQ Digest, Vol 37, Issue 6 Sébastien, Given the relatively low cost of the Artix-7 FPGAs, my preference is generally to go as big and as fast as reasonably possible. I don't want to find that, for example, we can't fit a hard FPU/fancy servo on Kasli because we saved $50 on the FPGA. Also, since gateware development is usually much more expensive than hardware, I'd rather go for dumb/inefficient gateware on big FPGAs than have to optimise the gateware to fit on a smaller FPGA. The fact that going for a 75T/100T gives us access to 12EEMs/Kasli (4 on the BP) rather than 10EEMs/Kasli (only 2 on the BP) for the 50T is an added benefit. Having said all that, if you think the 50T in the -2 speed grade won't be a limitation then I'm happy to go along with your recommendation... T ________________________________________ From: ARTIQ [[email protected]] on behalf of [email protected] [[email protected]] Sent: 29 June 2017 11:00 To: [email protected] Subject: ARTIQ Digest, Vol 37, Issue 6 Send ARTIQ mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit https://ssl.serverraum.org/lists/listinfo/artiq or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of ARTIQ digest..." Today's Topics: 1. Kasli FPGA selection (Sébastien Bourdeauducq) ---------------------------------------------------------------------- Message: 1 Date: Thu, 29 Jun 2017 12:23:04 +0800 From: Sébastien Bourdeauducq <[email protected]> To: Thomas Harty <[email protected]> Cc: "[email protected]" <[email protected]>, Grzegorz Kasprowicz <[email protected]> Subject: [ARTIQ] Kasli FPGA selection Message-ID: <[email protected]> Content-Type: text/plain; charset=utf-8; format=flowed On Wednesday, June 28, 2017 04:52 PM, Thomas Harty wrote: > Have we settled on the 50T as the FPGA for the first version of Kasli, > and what speed grade? I would advocate for the 50T in -2 speed grade for two main reasons: a) I don't think we need that much FPGA resources for the 100T to be needed. b) -2 speed grade transceivers go to 6.25Gbps whereas -1 speed grade ones go to 3.75Gbps. In addition to a significant increase in bandwidth, the -2 transceivers can use the same configuration on the Metlino/Sayma side which is used for the backplane (5Gbps). Otherwise we would have to generate another set of Ultrascale transceiver settings (and shave a yak) and potentially deal with weird RTIO frequency ratios in a hybrid MTCA/Eurocard Sinara system. Sébastien ------------------------------ Subject: Digest Footer _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq ------------------------------ End of ARTIQ Digest, Vol 37, Issue 6 ************************************ _______________________________________________ ARTIQ mailing list https://ssl.serverraum.org/lists/listinfo/artiq
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