Which FPGA is best for a coder for testing various HW configs?

[VladR]

I've been reading a lot about boards like mister, minimig, etc.

I do have 2 FPGA boards at home already - for Vampire and EclaireXL, but want to keep those intact (with cores they have) and need third one for Amiga stuff. I should get SpectrumNext later this year from second KS campaign (whenever it ships).

I reckon the "best" board would be the largest one that has most gates/logic, but if it's not being actively produced, I'm sure it commands a scalp price on eBay and for me it's not an item to collect and scalp, but an item to use daily (upload builds, test various CPUs, etc.).

What options are there currently on the market ? Depending on price I would select what makes most sense.



Please note that I am not looking at it from the point of view of a gamer that requires cycle-exact performance and feature set like original HW - for me the configurable CPU/RAM/AGA is more important.

Ideally, the board would allow me to quickly flash cores from A500 to whatever is currently the fastest (e.g. Motorola CPU) available core.

Also, it wouldn't hurt if I could flash some Atari ST cores and while I have Falcon at home, and assuming there even is a working core for Falcon, it would trump using the real machine for sure (for me).



Which brings me to another question - which Motorola CPUs have cores available right now ?

Is there a board that can somewhat approximate 68060-level of performance ? I believe there was a thread recently that 68040 is kinda the max right now ?



I don't realy follow the core scene regularly, so I figured I would ask and learn something new.

[Samurai_Crow]

The MISTer has the same FPGA as the Vampire standalone. It is based on the Terassic DE10 devboard. It has loads of cores for it including AtariST series. It stands the best chance of getting '060 performance.

The earlier MiST is expensive and has a much smaller FPGA. I have a SiDi which runs most of the MiST cores but has the same problem with the small FPGA. I wouldn't recommend these two.

[Lord Aga]

Is there a (n easy) way to connect a regular Amiga keyboard to a MISTer board? Thus making it a kind-of-replacement motherboard.

[NovaCoder]

Originally Posted by Lord Aga

Is there a (n easy) way to connect a regular Amiga keyboard to a MISTer board? Thus making it a kind-of-replacement motherboard.

Yes it's very easy to turn a MiSTer into a replacement motherboard

[ Show youtube player ]

The thing about the MiSTer is that it is so much more than an Amiga replacement, it can recreate most 80's and early 90's computer hardware brilliantly.

But the MiSTer project is more interested in cycle accuracy than performance so Amiga speed is not currently that impressive. The FPGA obviously has the size to me much faster but currently it's like a 40MHz 020 with RTG.

I doubt it will ever offer 060 level performance, the most we can hope for is a fast 030 with FPU support.

[Lord Aga]

Originally Posted by NovaCoder

Yes it's very easy to turn a MiSTer into a replacement motherboard

[ Show youtube player ]

But I can't see the connector in this video
Is it a big box Amiga type? Or an A500 sort?

Originally Posted by NovaCoder

But the MiSTer project is more interested in cycle accuracy than performance so Amiga speed is not currently that impressive.

That's actually quite all right I don't crave ludicrous speeds.

[Foebane]

I wish people wouldn't call these electronic devices by that name, it constantly reminds me of a GOLF CHAMPIONSHIP!

What the hell has GOLF got to do with electronics and computers???

[NovaCoder]

Originally Posted by Lord Aga

But I can't see the connector in this video
Is it a big box Amiga type? Or an A500 sort?

Nope, my Amiga uses USB

[Samurai_Crow]

As I said earlier, the FPGA in the MiSTer is the same as the Vampire standalone so it obviously is capable of ludicrous speeds if someone programs it to be. Current MiniMig cores have non-pipelined CPU cores. If someone were to make a core with a 4-stage pipeline it would double the speed. If someone added a second pipeline for superscalar execution it would double the speed again. If those pipelines used opcode fusions and bonding, it would be as fast as a Vampire. So don't say it's not capable of insane speed, say it isn't fast yet because the cores aren't there yet.

[Lord Aga]

Originally Posted by NovaCoder

Nope, my Amiga uses USB

Well, that doesn't help at all

[robinsonb5]

Originally Posted by Lord Aga

Well, that doesn't help at all

This - https://github.com/ByteMavericks/MiMimiKB - coupled with a cheap Arduino Leonardo / ProMicro clone is enough to interface an A500 keyboard to USB. (The power and drive LEDs can't be driven directly, though.)

As for performance, as it happens Mark Watson (author of the Atari 800 core) is currently working on hybrid emulation - allowing the ARM to emulate the 68k, leaving the chipset stuff to the FPGA - that should result in a big speed boost once he's got it working.


As for the best platform - there are many to choose from. The Turbo Chameleon 64 is really cool if you're a C64 fan, MiST and its various clones and derivatives, notably MiSTica and SiDi - are very nice - the newest UnAmiga and Neptuno are good options at the budget end (making use of a cheap Chinese dev board) - but the one with the widest range of available cores is of course MiSTer.

[NovaCoder]

Originally Posted by robinsonb5

As for performance, as it happens Mark Watson (author of the Atari 800 core) is currently working on hybrid emulation - allowing the ARM to emulate the 68k, leaving the chipset stuff to the FPGA - that should result in a big speed boost once he's got it working.

Yes I've heard talk if this hybrid approach before, looking forward to seeing it one day, will be super fast

[MickGyver]

Originally Posted by Lord Aga

Is there a (n easy) way to connect a regular Amiga keyboard to a MISTer board? Thus making it a kind-of-replacement motherboard.

I actually started working on a full Amiga 500 to MiSTer conversion "kit" today. I will make a thread about it soon.

[Lord Aga]

Yaaay
Go MickGyver!

@robinsonb5
Thanks for the explanation!

[chiark]

I love the misterfpga, it’s incredible. “byte Mavericks” mentioned above is me, and I’ve created a small board that drives the Amiga keyboard leds too...

There’s progress being made to offload cpu emulation to the arm side of things which is interesting, too...

[VladR]

Originally Posted by Samurai_Crow

The MISTer has the same FPGA as the Vampire standalone. It is based on the Terassic DE10 devboard. It has loads of cores for it including AtariST series. It stands the best chance of getting '060 performance.

The earlier MiST is expensive and has a much smaller FPGA. I have a SiDi which runs most of the MiST cores but has the same problem with the small FPGA. I wouldn't recommend these two.

Huh, so then I would have two same FPGA boards ? Interesting.

Well, at that point I guess I need to consider whether the annoyance of flashing back and forth is worth whatever the price of MISTer's DE10 board is. Or, in other words - is it worth it to have the ability to run the builds on Vampire AND other Amiga at the same time ? Especially considering that I would target non-Vampire 680X0 only after releasing a Vampire build first. Hmmmmm, something to ponder about...

As for the price, according to digiKey, it's $170 right now:
https://www.terasic.com.tw/cgi-bin/p...=1046&PartNo=1


Now, with MiSTer - do I just buy a board myself and flash it myself with USB Blaster ?


But, if I am just buying a board, then I should consider if there isn't a board that is slightly more expensive but has more gates/logic ?

I'd hate to find out 3 months later that if I only spent , for example, $30 more I could have had a FPGA board with, say, 2x gates/logic!

[VladR]

I guess the best approach to handling various levels of performance between 040-060 systems is just to implement level of detail and let player decide on the compromise between performance and visuals.


Looks like there's no real way around that amount of work...


And if we can't have 060 on an FPGA board yet, I might as well just continue benchmarking on WinUAE and just adjust the results by coefficients that have been measured on a real machine. Right now I can estimate the framerate on WinUAE at within 7% margin of error (against V2/V4).

Might as well just find somebody with 060, give him a build to run, collect the data and compute coefficients/multipliers to use on my WinUAE / excel scene breakdown...

[robinsonb5]

Originally Posted by chiark

I love the misterfpga, it’s incredible. “byte Mavericks” mentioned above is me, and I’ve created a small board that drives the Amiga keyboard leds too...

Ah cool! Thanks for publishing your version of that firmware - it works a treat, and we recently adjusted the MiST firmware with a minor hack so it works on MiST too (MiST only supports USB Boot Protocol which is basically what the Arduino keyboard library uses - but it doesn't signal that it's bootp capable to the computer.)

Originally Posted by VladR

As for the price, according to digiKey, it's $170 right now:

That's just for the base DE10-nano - you need more than that - for Amiga you need an SDRAM module (32 meg is enough for Amiga, 128 meg is needed for more advanced cores) and you'll want an IO board for audio, too.

Now, with MiSTer - do I just buy a board myself and flash it myself with USB Blaster ?

It has a built-in USB blaster, but you won't need that unless you start developing cores. It has a minimal Linux OS which boots very quickly, and that OS is in charge of loading cores from SD card.

I'd hate to find out 3 months later that if I only spent , for example, $30 more I could have had a FPGA board with, say, 2x gates/logic!

That depends on whether there's anything useful you can do with that 2x gates / logic!

As of right now, the Amiga core can be a cycle-accurate 68000, or it can be roughly equivalent to very fast '030. It's not likely to be a useful point of reference if you're targetting '040 / '060, even once the host-side emulation stuff works.

[NovaCoder]

For those interested in the MiSTer there is also a fitting kit available now for ATX (including CheckMate cases).

https://www.checkmate1500plus.com/Products.aspx?id=376

[VladR]

Originally Posted by Samurai_Crow

- If someone were to make a core with a 4-stage pipeline it would double the speed.
- If someone added a second pipeline for superscalar execution it would double the speed again.
- If those pipelines used opcode fusions and bonding, it would be as fast as a Vampire.

The moment you said it's same FPGA board I had the same thought - the baseline performance that fits on the FPGA board is what already exists and that's the superscalar architecture with 2 integer and fp/ammx.

Vampire is already maxing out the board,from what i could infer reading the forums, so it's hard to say exactly how much more performance could be extracted from that FPGA board without knowing how much space does each feature take.

But I would reckon that if we dumped AMMX, then we could have the current 2 integer cores plus a parallel FP unit.


Perhaps if those were simpler cores, 4 of them would fit ? Of course, that would be a non-existing Amiga HW, as there never ever was an Amiga quad-core and most people would revolt at such an "abomination" ...

[VladR]

Originally Posted by robinsonb5

That's just for the base DE10-nano - you need more than that - for Amiga you need an SDRAM module (32 meg is enough for Amiga, 128 meg is needed for more advanced cores) and you'll want an IO board for audio, too.

Cool.

Originally Posted by robinsonb5

It has a built-in USB blaster, but you won't need that unless you start developing cores. It has a minimal Linux OS which boots very quickly, and that OS is in charge of loading cores from SD card.

Well, I already have a blaster, but those are apparently cheap these days anyway.

Originally Posted by robinsonb5

That depends on whether there's anything useful you can do with that 2x gates / logic!

I can't do anything with those, that's for sure. The last thing I need to do is start playing with programming cores (as much as I would love to) - that would absolutely guarantee I never ever get to finishing my games...
But because FPGA space is the single most precious resource (from what I can infer indirectly), I figured it's worth asking if I shouldn't just splurge for a slightly more expensive board.

Originally Posted by robinsonb5

As of right now, the Amiga core can be a cycle-accurate 68000, or it can be roughly equivalent to very fast '030. It's not likely to be a useful point of reference if you're targetting '040 / '060, even once the host-side emulation stuff works.

Well, but at that point, it's not really much more useful [for me] than an emulator which if I recall correctly, can emulate 68000 pretty precisely these days. Not to mention that having a game that runs well on both 7 MHz 68000 and a 85 MHz superscalar Vampire is a mess to design due to 2 orders of magnitude performance difference...

Meaning, if I have to apply performance coefficients to each stage of the pipeline to estimate the final performance [on whatever HW config is being worked on], I might as well not bother with messing with an FPGA board in the first place, and just do all testing directly under WinUAE.