How FPGAs work, and why you'll buy one (2013) • Hacker News Board

Re: How FPGAs work, and why you'll buy one (2013)

#61

Post by cgag » Thu, Apr 16, 2015, 6:55 PM UTC

davexunit wrote: post #53

The major issue with FPGAs today is that there is no free toolchain for compiling the bitstreams that run on them. The only project I know of to make any real progress on fixing this is fpgatools. [0] It supports a single model of the Xilinx Spartan-6 series, the XC6SLX9. I know almost nothing about FPGAs, but seeing as how almost no one is working on this problem, I figured I'd try to add support for the XC6SLX45, t…

My roommate is working on this problem: http://diamondman.github.io/Adapt/ https://github.com/diamondman/Adapt

I don't understand this stuff well, I'll try to get him to comment here.

Re: How FPGAs work, and why you'll buy one (2013)

#62

Post by jamieiles » Thu, Apr 16, 2015, 6:58 PM UTC

fixxer wrote: post #17

Suppose I wanted to get started with FPGAs for purpose of computation (no interest in control or actuation of sensors/devices). What would be the best starting board for less than $300? I'm not a student, but I can probably find one if your suggestion is a student dev board.

The Terasic series are great, especially if you aren't too fussed about peripherals on the board. The DE0-nano has a decent sized FPGA and SDRAM for less than $100. There is also a SoC variant of this board coming soon with an integrated ARM subsystem.

Re: How FPGAs work, and why you'll buy one (2013)

#63

Post by alain94040 » Thu, Apr 16, 2015, 7:19 PM UTC

davexunit wrote: post #53

The major issue with FPGAs today is that there is no free toolchain for compiling the bitstreams that run on them. The only project I know of to make any real progress on fixing this is fpgatools. [0] It supports a single model of the Xilinx Spartan-6 series, the XC6SLX9. I know almost nothing about FPGAs, but seeing as how almost no one is working on this problem, I figured I'd try to add support for the XC6SLX45, t…

I disagree strongly. The major issue with FPGAs today is that they cost money (because they are chips). They cost even more than your CPU. So you can't treat them life software. To put it in simpler words: everyone has access to a CPU, less than 1% have access to an FPGA. Fix that* and the tooling will follow.

* one way to make FPGAs "free" is to incorporate some FPGA blocks in an Intel CPU. Then it will feel free.

Re: How FPGAs work, and why you'll buy one (2013)

#64

Post by catern » Thu, Apr 16, 2015, 7:22 PM UTC

What I'm having trouble understanding (as just a regular, not-hardcore programmer) is this: What end-user advantage will cause people to buy devices that include FPGAs? What use are they to a consumer? What interesting programs or devices can be created with an FPGA that can't be done otherwise?

Basically, if "everyone can easily create whatever custom objects they need!" is the utopian vision for 3D printers, and "everyone can self-host their services and protect their privacy and freedom!" is the utopian vision for a home server[0], what is the utopian vision here?

[0] Such as one running https://sandstorm.io/

Re: How FPGAs work, and why you'll buy one (2013)

#65

Post by davexunit » Thu, Apr 16, 2015, 7:24 PM UTC

sklogic wrote: post #57

davexunit wrote: post #53

The major issue with FPGAs today is that there is no free toolchain for compiling the bitstreams that run on them. The only project I know of to make any real progress on fixing this is fpgatools. [0] It supports a single model of the Xilinx Spartan-6 series, the XC6SLX9. I know almost nothing about FPGAs, but seeing as how almost no one is working on this problem, I figured I'd try to add support for the XC6SLX45, t…

Wow! How did I managed not to know of this project?!?

Want to help with the XC6SLX45? :)

Re: How FPGAs work, and why you'll buy one (2013)

#66

Post by alain94040 » Thu, Apr 16, 2015, 7:27 PM UTC

aprdm wrote: post #9

Igglyboo wrote: post #7

The trouble I had with FPGAs is how radically different languages like Verilog and VHDL are when compared to languages like Java, Python, or C++. Writing code that is concurrent by default is a massive paradigm shift when all I had been exposed to at that point were procedural languages.

Try to start modeling your problem as a state machine. Separate the combinational and the sequential part in two state machines. The flow becomes quite similar to regular embedded system software (that can be programmed using state machine pattern as well). Say e.g: state read_input => reg_a state multiply_input_by_10 => reg_b state send_to_output => finish_reg and then parallel to that you would have finish_wire or…

I started writing a (hopefully) better and clearer tutorial of what is HDL for programmers. Feel free to contribute at https://en.wikibooks.org/wiki/Programmable_Logic/Verilog_for...

Re: How FPGAs work, and why you'll buy one (2013)

#67

Post by sklogic » Thu, Apr 16, 2015, 7:30 PM UTC

davexunit wrote: post #65

sklogic wrote: post #57

Earlier quoted context omitted.

Wow! How did I managed not to know of this project?!?

Want to help with the XC6SLX45? :)

Maybe. I've got an Atlys board (but I'm not sure I'm ready to brick it yet).

Currently I'm more interested in trying to use it with the existing open source place&route tools ( https://code.google.com/p/vtr-verilog-to-routing/ ).

Re: How FPGAs work, and why you'll buy one (2013)

#68

Post by vardump » Thu, Apr 16, 2015, 7:31 PM UTC

solve wrote: post #6

nkurz wrote: post #2

A sequel is in the making, titled "Why you won't buy an FPGA" Did the followup article ever get written? I didn't find anything with a search for the proposed title on either his site or Google.

The reason is because GPUs gained more general-purpose capabilities. GPUs are the new FPGA, for all practical purposes.

FPGAs can respond to signals in nanoseconds, talk to directly different peripherals (integrated circuits, SPI, DDR3, SATA, HDMI - whatever). State machines can "branch" on every clock cycle.

GPUs... usually respond in milliseconds. Usually can't talk with anywhere except host across PCIe bus. State machines and branches... uh, yeah, don't do those on a GPU!

Maybe tile CPUs will give FPGAs a fight in the future in some market segments. Easy (well, easier than FPGA) programmability and potentially good I/O. Transputer was so amazing back in the day. 30 years ago. Maybe Tilera and such will eventually succeed?

Anyways, FPGAs and GPUs are very different beasts.

Re: How FPGAs work, and why you'll buy one (2013)

#69

Post by fit2rule » Thu, Apr 16, 2015, 7:43 PM UTC

sklogic wrote: post #57

davexunit wrote: post #53

The major issue with FPGAs today is that there is no free toolchain for compiling the bitstreams that run on them. The only project I know of to make any real progress on fixing this is fpgatools. [0] It supports a single model of the Xilinx Spartan-6 series, the XC6SLX9. I know almost nothing about FPGAs, but seeing as how almost no one is working on this problem, I figured I'd try to add support for the XC6SLX45, t…

Wow! How did I managed not to know of this project?!?

Maybe you also don't know about this project?

http://www.clifford.at/icestorm/

They had some interesting progress lately:

http://hackaday.com/2015/03/29/reverse-engineering-lattices-...

Re: How FPGAs work, and why you'll buy one (2013)

#70

Post by vonmoltke » Thu, Apr 16, 2015, 7:43 PM UTC

frozenport wrote: post #54

vonmoltke wrote: post #33

Earlier quoted context omitted.

One of the biggest problems is how insular and impenetrable that community is. The FPGA community, and to a certain extent the entire semiconductor industry, seems to have a prescribed path for engineers. First, you get an electrical or computer engineering degree with a couple internships at semiconductor companies. Then, you get a junior role at one of those companies where you are mentored by senior engineers, who…

This is non-sense, consider the thousands of self taught FPGA programmers in Asia.

I was not aware there were thousands of self-taught FPGA programmers in Asia. Even accounting for that: a) I'll wager most are using pirated software; b) that number pales in comparison to the billions of people and millions of self-taught programmers in Asia; c) they still have a snowball's chance in hell of working for or otherwise influencing Western hardware companies.