FMC, PMOD, and .... SYZYGY

[PDXjason]

This week, we at Opal Kelly Incorporated announced the release of SYZYGY, a new peripheral interface specification for FPGA systems.

Cue XKCD #927 https://xkcd.com/927/

Right--we understand that it's another standard, but there aren't a lot of standards in this specific space--and it's something that we (and our customers) have continually found a need for higher performance peripherals at a price point way lower than FMC for implementation.

Try it, you just MIGHT like it--or at least appreciate that there's another tool in the toolbox.

"We envision SYZYGY occupying the space between present standards where pin economy, low cost, and high performance converge.  SYZYGY is free to license to encourage consistency, proliferation, and a healthy ecosystem where carrier and peripheral manufacturers, semiconductor device manufacturers, educational institutions, and research organizations are invited to develop their own additions".

SYZYGY offers higher performance and higher pin count than Digilent's PMOD but without the expense and ultra-high pin count of FMC.

We have also created a dedicated website with additional information to spread the word. You can download the spec and find other pertinent info there. http://syzygyfpga.io/

[Scrts]

Is it the 3 times shorter version of Altera's widely used HSMC connector?

[ehughes]

Pronunciation?

[hamster_nz]

IMO a (very nice looking) web site won't help you as much as offering free samples of connectors, somewhere you can get them in low numbers for close to volume cost, and maybe break-out boards to existing standards (eg. PMOD to SYZYGY)

For low speed stuff I can get 0.1" headers anywhere, for less than $0.25 for a 40-way male+female pair.

http://www.dx.com/p/1x40-pin-2-54mm-pitch-straight-single-row-pcb-female-headers-80pcs-464395
http://www.dx.com/p/single-row-40-pin-2-54mm-pitch-pin-headers-200-piece-pack-138332

Underneath it's ugliness, PMOD has a beauty in that it uses cheap, widely available parts from or anybody's junk draw.

I agree that an light-weight, inexpensive solution is needed for transceivers... FMC connectors are daunting.

[Cerebus]

Pronunciation?

Down a quart of whiskey and then try and say "sausages".

[KE5FX]

IMO a (very nice looking) web site won't help you as much as offering free samples of connectors, somewhere you can get them in low numbers for close to volume cost, and maybe break-out boards to existing standards (eg. PMOD to SYZYGY)

For low speed stuff I can get 0.1" headers anywhere, for less than $0.25 for a 40-way male+female pair.

http://www.dx.com/p/1x40-pin-2-54mm-pitch-straight-single-row-pcb-female-headers-80pcs-464395
http://www.dx.com/p/single-row-40-pin-2-54mm-pitch-pin-headers-200-piece-pack-138332

Underneath it's ugliness, PMOD has a beauty in that it uses cheap, widely available parts from or anybody's junk draw.

I agree that an light-weight, inexpensive solution is needed for transceivers... FMC connectors are daunting.

There probably aren't many cases where you'd be tempted to go from PMOD to Syzygy, just because the performance envelope is so much bigger with the Samtec connectors.  Those 0.1" connectors (especially with such small pin counts) are not useful for anything remotely serious.  Meanwhile, the fine-pitch Samtec connectors aren't a good match for basic educational and hobby users.

A standardized alternative to FMC, on the other hand, is a Good Thing.  Those are very awkward to deal with.

It might be nice to see higher pin counts in future revisions of the Syzygy spec, since the Samtec connectors don't seem to get much more expensive (or harder to work with) as the pin count goes up.  This could allow more differential pairs to be defined.

JESD204B is another pain point experienced by people working with these sorts of devices, so perhaps Opal Kelly could add some value by providing a free core for users of their Syzygy-compatible boards.    AFAIK no one has released a genuinely-free JESD204B core yet.  The FrontPanel API already supports high-speed streaming so it really would just be a matter of providing the necessary IP.

[KE5FX]

Opal Kelly? No. I refrain from touching anything from Opal Kelly, even open standards. Their profit margin is just insane.

(Shrug) Their stuff Just Works(tm), and that covers a multitude of sins.  Part of their markup is accounted for by the value added by the FrontPanel API.  Opal Kelly boards are definitely overpriced if you can take responsibility for the whole data path from the FPGA to the PC application.  If you can do that, you're better off with ZTex or Trenz or Xess or similar vendors who are more "open" as well as more economical.  But a lot of shops don't have that kind of programming experience in-house.  For those customers -- and they certainly do exist -- Opal Kelly is providing a substantial time-to-market advantage, not just hardware by itself. 

I used Opal Kelly boards myself in a project several years ago, in which I didn't want to design a separate FPGA daughterboard and deal with BGA assembly.  They worked very well for that purpose.  But since I wasn't using their API I had to spend a lot of time reverse-engineering the product I was buying, and that was kind of irritating.  Nowadays 4- and 6-layer PCBs capable of supporting 0.8 mm BGAs are practically free for the cost of shipping from China, so I'd be much less reluctant to spin my own daughterboards.  It makes sense for them to look for opportunities to add value elsewhere.

[pdxjake]

Thanks for posting this Jason! It's nice to spark up a conversation.

SYZYGY is pronounced the normal way.   https://www.merriam-webster.com/dictionary/syzygy has an audible pronunciation.

As we mention in our FAQ (http://syzygyfpga.io/faq/), PMOD is great and is very appropriate for small, low bandwidth devices with limited pin count. SYZYGY is intended for the up-market peripherals such as communication DAC/ADC (think 40 - 150 MSPS), machine vision, etc. PMOD is not well-suited to these devices. FMC is actually well-suited to these devices, but consumes a lot of FPGA pins and is (as KE5FX mentioned, daunting for some).

Regarding free samples... Samtec has an excellent samples program and Digi-Key stocks these connectors as well.

Regarding interfaces to other standards... A SYZYGY to 4-PMOD adapter is on our roadmap (http://syzygyfpga.io/peripherals/) to release with the HUB carrier later this year.

Please remember, SYZYGY isn't intended to replace PMOD or FMC. It's intended to fill the space between these two and provide a home base for peripherals that aren't comfortable at the extremes.

Cheers!