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Cheap FPGA Development Boards

joelw.id.au

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Re: Cheap FPGA Development Boards

#51

Post by fieldprogaway »

IgorPartola wrote: post #41

I have always been curious about FPGAs and I think I understand the concept, but what could someone provide some use cases for why you might want one (that aren’t calculating SHA-1 hashes)? As someone who understands microcontroller programming and wiring, what cool things could I do with an FPGA that I would have a hard time doing with other hardware?

Esoteric communication interfaces and situations where you want to address a lot of devices in parallel.

It's kind of a stretch, but take a wall of addressable LED strips like WS2812s as an example. Color data is sent along one wire as precisely-timed pulses, 1.25us per bit.

You can drive a few strips using critical sections written in assembly, or misusing SPI peripherals if your clock speed can easily divide into ~2.4MHz. But you'd be hard-pressed to run dozens of parallel LED strips with a good framerate.

On an FPGA, you can just write an "LED" module and add as many of those modules as you can fit into the chip. You can also decide whether to include a simple CPU in the design, or use another method of processing lighting patterns.

They're flexible, but they are also expensive enough that it's kinda hard to find somewhere that they make sense. A "cheap FPGA" price point of $50-150 is still an order of magnitude pricier than a cheap microcontroller board ($2-10).

Re: Cheap FPGA Development Boards

#52

Post by snvzz »

tyingq wrote: post #8

If you need 5V compatibility, or large sizes for cheap, search eBay for [altera university]. Since these boards were mandatory for many classes there are pretty easy to find for under $50, and include lots of peripherals, buttons, LEDs, connectors, etc. The cheap ones are old, of course, but still useful.

I need 5v but I don't think any of the few FPGA chips that support 5v are actually usable with the Symbiflow stack.

I do wonder what's the best way to translate to 5v and back. There has to be some fast-switching, go-to part for the purpose.

Re: Cheap FPGA Development Boards

#53

Post by IgorPartola »

fieldprogaway wrote: post #51
IgorPartola wrote: post #41

I have always been curious about FPGAs and I think I understand the concept, but what could someone provide some use cases for why you might want one (that aren’t calculating SHA-1 hashes)? As someone who understands microcontroller programming and wiring, what cool things could I do with an FPGA that I would have a hard time doing with other hardware?

Esoteric communication interfaces and situations where you want to address a lot of devices in parallel. It's kind of a stretch, but take a wall of addressable LED strips like WS2812s as an example. Color data is sent along one wire as precisely-timed pulses, 1.25us per bit. You can drive a few strips using critical sections written in assembly, or misusing SPI peripherals if your clock speed can easily divide into ~…

Oh interesting. So basically instead of using 20 Arduinos I can make an FPGA into a custom LED driver where I hand it a bitmap and it communicates the image to the LED matrix? That sounds pretty neat.

Re: Cheap FPGA Development Boards

#54

Post by rthomas6 »

IgorPartola wrote: post #45
rthomas6 wrote: post #43

Earlier quoted context omitted.

Most things you can do with a custom ASIC chip you can do with an FPGA, except with slower clock speeds. High speed signal processing, massive parallel designs, custom anything pretty much. You can (and often do) even have processors inside the FPGA running software. Some real world applications include a lot of video encoding and processing, cellular stuff, electronic warfare and radar applications, self driving car…

Thanks. So like what do hobbyists use them for? Like why would you buy one to mess around with? And what is electronic warfare?

Some things a hobbyist might use one for:

* Experimental processor design. If you want to make a processor with its own custom instruction set, or modify an existing processor design, you need an FPGA to actually see it in action.

* Synthesizers and audio filters. You can do a lot of low latency signal processing compared to even a beefy microcontroller with an FPGA, so if you want to make your own synth sounds in hardware, an FPGA might make sense.

* Computer vision stuff. If you want to make some gadget that does some kind of image processing that is streaming from a camera, and FPGA would work, especially if you wanted it to be small/portable.

* High bandwidth or low latency SDR applications.

Re: Cheap FPGA Development Boards

#56

Post by justinclift »

baybal2 wrote: post #55
justinclift wrote: post #42

Earlier quoted context omitted.

External stepper motor drivers. eg: http://leadshine.com/ProductSubType.aspx?type=products&categ...

Driving a stepper directly from FPGA? Why?

Seemed to be more a question of "why 5v at all?", rather than meaning FPGA-specific. ;)

Re: Cheap FPGA Development Boards

#57

Post by tyingq »

snvzz wrote: post #52
tyingq wrote: post #8

If you need 5V compatibility, or large sizes for cheap, search eBay for [altera university]. Since these boards were mandatory for many classes there are pretty easy to find for under $50, and include lots of peripherals, buttons, LEDs, connectors, etc. The cheap ones are old, of course, but still useful.

I need 5v but I don't think any of the few FPGA chips that support 5v are actually usable with the Symbiflow stack. I do wonder what's the best way to translate to 5v and back. There has to be some fast-switching, go-to part for the purpose.

Unfortunately, there's not a good single solution. Best depends on single vs bi-directional (also, which direction), switching speed, tristate or not, etc.

Re: Cheap FPGA Development Boards

#58

Post by disqard »

IgorPartola wrote: post #41

I have always been curious about FPGAs and I think I understand the concept, but what could someone provide some use cases for why you might want one (that aren’t calculating SHA-1 hashes)? As someone who understands microcontroller programming and wiring, what cool things could I do with an FPGA that I would have a hard time doing with other hardware?

Thank you for asking this question! Like you, I have some experience with microcontrollers and have lately been kinda curious about getting into FPGAs.

I learned some good perspectives from the replies to your query.

Re: Cheap FPGA Development Boards

#59

Post by snvzz »

tyingq wrote: post #57
snvzz wrote: post #52

Earlier quoted context omitted.

I need 5v but I don't think any of the few FPGA chips that support 5v are actually usable with the Symbiflow stack. I do wonder what's the best way to translate to 5v and back. There has to be some fast-switching, go-to part for the purpose.

Unfortunately, there's not a good single solution. Best depends on single vs bi-directional (also, which direction), switching speed, tristate or not, etc.

I do pretty much need to interface a 68000 bus.

D lines and some signals need to be bidirectional. And I might even need to do bus mastering, so most signals would have to be.

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