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How FPGAs work, and why people will buy them (2013)

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Re: How FPGAs work, and why people will buy them (2013)

#81
post #17

Earlier quoted context omitted.

IEEE tracks a vast number of open standards and specifications (e.g., Ethernet, WiFi, Bluetooth). I guess the comment was pointing out that there is a degree of openness in EE.

> IEEE tracks a vast number of open standards And demands mega-bucks for a PDF of any of those standards

So how do you propose a non-profit like the IEEE make money?

Re: How FPGAs work, and why people will buy them (2013)

#82
post #5

> FPGAs are a programmable platform, but one designed by EEs for EEs rather than for programmers. This is the problem with FPGAs. Their performance and utility is not really disputed. Working with them is so un-ergonomic that it's frankly embarrassing. The EE world is notoriously closed/proprietary making it incredibly difficult to explore novelty or customize tooling to suit specific needs. The situation is reminisc…

I too decry the lack of openness with respect to the data file encoding which would allow for more open source tools to be created. I had a hilarious discussion with Xilinx's VP of tools about this[1]. The interesting thing about HDLs and HDL work flows is that they can "look" like software and yet not be software. VHDL and Verilog are the only "languages" I know where you can write something that is both syntactical…

verilog has behavioural and synthesizable subsets. One is intended for testing, the other for hardware generation. Once you understand this you can learn which constructs, though syntactically correct, should not be used for hardware generation.

Also HDLs are not alone in having 'quirks' that experienced engineers need to know about.. c/c++ for example. cough undefined behaviour cough

Code coverage and quality checking tools are quite good in the EE world, verification has some powerful tools to almost eliminate hardware bugs - which is especially important for asic design.

On the open sourcing of tools - there are free ones, that target real FPGAs - so can you say why these have not surpassed vivado? In fact, while impressive in their own right, they are very primitive in comparison to vivado despite being open source for years. The open source verilog tools also don't fully support all of verilog 2008/2012.

So I don't buy the open sourcing argument for the synthesis and pnr tools would dramatically affect FPGA sales. Instead higher level compilation and abstraction may be the key.

Re: How FPGAs work, and why people will buy them (2013)

#83
post #74
post #63

Earlier quoted context omitted.

What does leaving the sandbox mean when implementing an FPGA? I'm not aware of any soft resource one can't completely control in Vivado/Xilinx as every hard resource can be completely described in your own design via the primitive library. That doesn't mean it is always a good idea, but one can do it.

> described in your own design via the primitive library There's your sandbox EDIT: If you cannot replace their tools with yours, it is a sandbox.

The elements in the primitive library directly map to the hardware components available on the FPGA. There's no "sandbox" involved.

Re: How FPGAs work, and why people will buy them (2013)

#84
post #75
post #73

Earlier quoted context omitted.

> Xilinx tools are free, as in beer This is untrue. [1] > Supporting code is a huge overhead and it's not clear, to me anyway, what Xilinx gains from the expendature. In what world is this the case? You host the project on github or the like and let people contribute bug fixes at the cost of filtering pull requests. Letting the community contribute bug fixes is a huge reason companies open source their tools. [1]: ht…

From your link: Vivado HL WebPACK™ Edition: no-cost, device-limited version of the Vivado HL Design Edition It's not as simple as an upload to github. https://opensource.com/business/16/5/how-transition-product-...

The keywords are "device-limited". Xilinx WebPack won't build bitstreams for some of the larger and faster devices.

Re: How FPGAs work, and why people will buy them (2013)

#85
post #8
post #6

Earlier quoted context omitted.

One exception, the ICE range from Lattice which have a open source tool-chain https://en.wikipedia.org/wiki/ICE_(FPGA)

AFAIK that tool-chain is thanks to the reverse engineering efforts of an individual and not Lattice itself. It's a step towards the right direction, but not really a first class vendor supported tool.

That's where GCC was circa 1988.

Re: How FPGAs work, and why people will buy them (2013)

#86
post #72

Earlier quoted context omitted.

I too decry the lack of openness with respect to the data file encoding which would allow for more open source tools to be created. I had a hilarious discussion with Xilinx's VP of tools about this[1]. The interesting thing about HDLs and HDL work flows is that they can "look" like software and yet not be software. VHDL and Verilog are the only "languages" I know where you can write something that is both syntactical…

The arguement in [1] doesn't make sense to me. Xilinx tools are free, as in beer, and the sale of ICs funds those tools so they are implementing your system of a "tax on every chip". Surely the VP of tools at Xilinx knows this. What problem are you unable to solve with an FPGA because you do not have the source code to Vivado? I understand why Xilinx doesn't want to release their source. They don't want to support it…

My argument for the VP was essentially not to release their source, rather to release all of the details that you need to create, sign, and then load a bitmap file into their FPGAs. Also to document how the chip is laid out, and how you can floorplan it by hints in the .bit file.

If they did just that, then the source code would "appear" as people wrote back ends for the various open source HDLs that are already in existence.

The challenge that I see is that Xilinx has already had the experience of selling that data to vendors like Synopsis who sell their own synthesis tools and charge major money for them. And like a person who holds an unvested stock option for a stock that goes from price A above the strike price, to a price B that is below the strike price, they feel as if they "lost" money. Similarly, Xilinx can't see "giving up" thousands, if not millions of licensing dollars they are getting from tools vendors, just to enable an open source community to start. Because they fundamentally can't see that having a vibrant open source ecosystem benefits all players. And this in spite of the gcc example which is pretty incontrovertible in my opinion.

Re: How FPGAs work, and why people will buy them (2013)

#87
post #72

Earlier quoted context omitted.

The arguement in [1] doesn't make sense to me. Xilinx tools are free, as in beer, and the sale of ICs funds those tools so they are implementing your system of a "tax on every chip". Surely the VP of tools at Xilinx knows this. What problem are you unable to solve with an FPGA because you do not have the source code to Vivado? I understand why Xilinx doesn't want to release their source. They don't want to support it…

My argument for the VP was essentially not to release their source, rather to release all of the details that you need to create, sign, and then load a bitmap file into their FPGAs. Also to document how the chip is laid out, and how you can floorplan it by hints in the .bit file. If they did just that, then the source code would "appear" as people wrote back ends for the various open source HDLs that are already in e…

They do document how the chip is laid out and exactly what HW resources the chip has. If you want to make your own backend you can. Use the get_ set_ property of physical constraints, extract and redo placement on the entire design via TCL, or save to your own intermediate file and work off that. I don’t think one needs access to Xilinx’s binary formats.

Re: How FPGAs work, and why people will buy them (2013)

#88
post #3

Earlier quoted context omitted.

And to be fair, since then FPGAs have exploded in non ASIC prototyping use cases. They're even starting to be used for some consumer electronics.

I'm interested in seeing some examples of their use in consumer electronics. I think this article would be a lot more compelling if it had a section on "You've already bought one if you have a (hypothetically) Roomba vaccum/ Tesla Model S/ Thinkpad laptop/ Ubiquiti router." I'm pretty sure most of those don't have FPGAs, but would be curious to see a list of things which do. I am by no means a representative consumer…

I was surprised to learn that Roland's JP-08 synthesizer uses an FPGA to simulate an analog synth.

https://youtu.be/zIFLdka9kTM?t=7m34s

Re: How FPGAs work, and why people will buy them (2013)

#89
post #79

This article makes me wonder if adding FPGA units to existing CPUs and GPUs that integrate with existing silicon makes a lot more sense than having a completely separate FPGA.

Do checkout Xilinx's Zynq series or Altera's Cyclone series, I think that may be what you're inferring ?

Re: How FPGAs work, and why people will buy them (2013)

#90
post #81

Earlier quoted context omitted.

> IEEE tracks a vast number of open standards And demands mega-bucks for a PDF of any of those standards

So how do you propose a non-profit like the IEEE make money?

Collecting $ from member orgs, and not from hobbyists who just want to tinker? How else do you propose to raise the next generation of hackers? By charging them $6000 to simply see a spec they have a minute interest in tinkering with?
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