FPGA CPU Board

[pmprog]

People (including myself) have thrown around the idea of an FPGA CPU board for inside the Pyra.

Anyway, interestingly, I came across this project on Hackaday today...
https://hackaday.io/project/77110-spartan-mini-fpga-handheld-nes

Regarding battery life, here's a quote

I'm going to swap out the Alkaline batteries for some NiMH 2100mAh rechargeable batteries. The total current drain of this project as measured by my power supply was around 400mA, so hopefully that should give me around 5 hours or so of operation before recharge. All in all I'm happy with how this project turned out. It was a lot of fun diving into FPGA's and being challenged by aspects of electronics that I hadn't encountered before

So who knows, might not be completely out of scope for a Pyra board.

 

[rSl]

cool project! would totally love an pyra fpga powered cpu-board.
boot up, select the system core of your choice, the pyra *becomes* this system. no emulation involved.
= want!!

 

[TrashyMG]

It would be a cool idea, but it would need some serious thought on design and likely need a strong base of people that have the skills to create and modify FPGA cores to custom hardware. While I do know a bit of people from the Apollo core/ Vampire team ( Amiga FPGA accelerator). I know they have their plate full with their current and future products. Plus they're only focusing on Amiga and AtariST, Motorola 68k processor for the most part.

 

[pmprog]

It would be a cool idea, but it would need some serious thought on design and likely need a strong base of people that have the skills to create and modify FPGA cores to custom hardware.

Absolutely. I mainly pointed this project out because it was the first handheld fpga device I'd seen, and his battery life sounded pretty good

 

[Bernd]

FPGA's are power hungry and create a lot of heat.
That means an active cooling.

Just my two Euro Cents.

 

[Eight Bit]

FPGA's are power hungry and create a lot of heat.
That means an active cooling.

Just my two Euro Cents.

My U64 has no active cooling and doesn't get as hot as my C64

 

[TrashyMG]

FPGA's are power hungry and create a lot of heat.
That means an active cooling.

Just my two Euro Cents.

What FPGAs are you using? are you data mining? I know that Altera Cyclone series are perfectly suited for retro systems and can be powered on USB with no active cooling.

 

[pmprog]

And just look at the TurboChameleon64... It has 2 FPGA chips inside a case the size of a C64 cart and also boots via USB power

http://www.syntiac.com/chameleon.html

Regarding the power usage, well, that's why I quoted the guys project. Yes its not as great as a super low power CPU, but still somewhat usable

 

[levi]

Regarding the power usage, well, that's why I quoted the guys project. Yes its not as great as a super low power CPU, but still somewhat usable

Yes, if all you want to use it for is emulating a 30 year old 6502 and proprietary video chip. As a CPU board for the Pyra, I suggest it would limit the functionality somewhat

 

[Eight Bit]

Hmm... I was thinking about putting a laptop battery in my U64 breadbin case...

 

[pmprog]

Yes, if all you want to use it for is emulating a 30 year old 6502 and proprietary video chip. As a CPU board for the Pyra, I suggest it would limit the functionality somewhat

Well, there's Amiga, Megadrive and SNES cores these days (I don't know how many are opensource, though I have seen a Megadrive core and Amiga (Minimig) core ported for the TC64). So if you get the board to configure the FPGA from SDcard/eMMC, then you have access to several machines with no OS overheads.

There are some cores provided by Altera and Xilinx that are capable of running Linux too (see here), so you might be able to wire up the modem/GPS/WiFi. Sure it won't be as fast as a physical ARM SoC, but might be handy if you are on the FPGA board for some small tasks.

I can see you point vs an ARM SoC depending on what your planned use-case for the Pyra is. If you're purely a retro game fan and not buying the 3G version, it might just provide a nice sleek portable gaming system to play games without OS overheads.

That said, I've never investigated the performance difference between Software Emulation vs FPGA Implementations

 

[Hellfleck]

there is static power consumptions which you will always have, the more gates the FPGA has the higher this will be

but then there is the dynamic power consumptions which happens when transistors are switching e.g. capitances are charged / discharged and inductance at higher frequencies etc. ... each time this happens draws a small amount of power which is turned into heat - might be tiny at 1 or 2 MHz for a NES / SNES core but if you step up the clock to modern speeds FPGAs will need cooling

you would probably need a small microcontroller e.g. ARM core to be able to step the clock down if the FPGA starts running hot ... I think I remember seeing some FPGA chips with an added ARM core, the ARM core could run as OS / hardware interface and feed the FPGA then basically use the core running in the FPGA as a coprocessor

ah found it again : https://www.electronicsweekly.com/news/business/intel-integrates-fpga-arm-cpu-2017-10/
would be interesting but this one is probably impossible to get and very pricey

edit: this was an extremly bad example, can order them only 20k for each chip

but Altera made similar ones (smaller, cheaper) too a few years back

 

[levi]

Well, there's Amiga, Megadrive and SNES cores these days (I don't know how many are opensource, though I have seen a Megadrive core and Amiga (Minimig) core ported for the TC64). So if you get the board to configure the FPGA from SDcard/eMMC, then you have access to several machines with no OS overheads.

True, but my issue is with your quote it's using 400ma. As hellfleck explained, that's only true in the specific instance with the FPGA gates confingured in that way. With more gates actively flip-flopping and at higher speeds it'll draw more juice.

It's interesting that you can run a slightly old Amiga core on it though.

I can see you point vs an ARM SoC depending on what your planned use-case for the Pyra is. If you're purely a retro game fan and not buying the 3G version, it might just provide a nice sleek portable gaming system to play games without OS overheads.

That said, I've never investigated the performance difference between Software Emulation vs FPGA Implementations

Yeah, me neither. I'd certainly be interested to see how that number changes running more performant core simulations.

 

[pmprog]

Cyclone V SoC 5CSEMA5F31C6 is on Mouser at 174eur (the UK site was down)
https://eu.mouser.com/ProductDetail/Intel-Altera/5CSEMA5F31C6N?qs=sGAEpiMZZMsT5lMbZ%2bWfIGuJbZ/2LrcT

True, but my issue is with your quote it's using 400ma. As hellfleck explained, that's only true in the specific instance with the FPGA gates confingured in that way. With more gates actively flip-flopping and at higher speeds it'll draw more juice

Sure, I understand that; and I appreciate that it could be that the board would be realistically unusable for anything other than some 8bit machines, and even then might still be out-performed and out-priced by an ARM SoC with emulators.

On the other hand, if you built an ARM or x86 core (there's a few around), you could be running a totally open platform - where you could fix Spectre and Meltdown issues if you wanted (obviously at the cost of speed/battery life etc.)

So yeah, I don't really know how good/practical/useful it would be, but as somebody else had worked on an FPGA handheld, thought it was interesting to raise it again

 

[JonnyH]

Cyclone V SoC 5CSEMA5F31C6 is on Mouser at 174eur (the UK site was down)
https://eu.mouser.com/ProductDetail/Intel-Altera/5CSEMA5F31C6N?qs=sGAEpiMZZMsT5lMbZ%2bWfIGuJbZ/2LrcT


Sure, I understand that; and I appreciate that it could be that the board would be realistically unusable for anything other than some 8bit machines, and even then might still be out-performed and out-priced by an ARM SoC with emulators.

On the other hand, if you built an ARM or x86 core (there's a few around), you could be running a totally open platform - where you could fix Spectre and Meltdown issues if you wanted (obviously at the cost of speed/battery life etc.)

So yeah, I don't really know how good/practical/useful it would be, but as somebody else had worked on an FPGA handheld, thought it was interesting to raise it again

I'd love a "playground" device like this too - you can even get fpgas with arm hardcores and ddr interfaces that can boot linux and act as a host for the fpga logic - allowing you to even modify stuff "live" on device.

But I don't know if they have framebuffer/display out and stuff like that. And power concerns likely means you can't run much more than an equivalent software emulator running on a similarly powered arm core could do anyway... but it's cool for a dev device

 

[Linux-SWAT]

I've just tried this board by Xilinx:
http://www.pynq.io/

It's quite nice, the I/O are good and the A9 does the job.
Jupyter is a bit weird for a terminal user, but interesting still. Anyway, the FPGA can also be used with standard VHDL/Verilog.

 

[second exodous]

Man, if someone makes a new CPU board for the Pyra that would be so cool. It would make the Pyra much more attractive to hackers. ED would be able to sell the other boards also.

 

[Hellfleck]

Cyclone V SoC 5CSEMA5F31C6

thats an interesting one and they claim lower power usage than before - they even provide a power estimate calculation tool, sadly thats a 10mb big excel file with its own, seperate handbook

1,1V device which means it needs expert work for a reliable PCB, good board house and manufacturing ... throw in some more components, worktime, manufacturing cost, low volume pricing, a tiny profit for ED and sales tax I would guesstimate you end up with a 450-500€ per piece price


what kind of price would be reasonable for such a board ? 250 € perhaps ? so we could narrow down and see if there are matching parts available at reasonable price points ?

 

[daveshah]

The Zynq UltraScale+ could be fun - it has a quad core Cortex-A53, Mali400 graphics acceleration on some models, loads of logic elements and good Linux support and single quantity availability - but it's also not cheap, and power consumption could be an issue.

 

[pmprog]

I've just tried this board by Xilinx:
http://www.pynq.io/

Looks interesting, and HDMI in and out

For higher performance, you can also use C/C++ with PYNQ. The Xilinx SDK software development environment is available for free and supports the PYNQ-Z1

So does this mean you can design the FPGA using C/C++? or have I misunderstood something?