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AuthorTopic: Motorola 68060 FPGA replacement module (idea)  (Read 26963 times)

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Offline freqmax

Motorola 68060 FPGA replacement module (idea)
« on: January 06, 2013, 08:22:41 AM »
In another thread the issue that there are too few fast Motorola 68060 CPUs around came up. But that a solution could be to join a male socket and a FPGA on top of that. Much like the 486- or pentium  overdrive solutions for the x86.

The MC68060 datasheet provides the PGA 206 pinout at page 356. And the frequency span is 0 - 75 MHz. Power (p328, p344) requirement is 3.3V +/- 5% @ 2A with 5V compatible I/O. There has not been any QFP variant on the commercial market, ever?

So this is what the FPGA has to be able to work with. Some kind of onboard DC/DC circuit will be needed. The voltages of iVDD, EVDD, PVDD and CVDD is unclear especially in a mixed 040/060 environment. So the question becomes, can a powerfull enough FPGA that implements 060 make do with 6.6 W ? and will the mechanical size be within limits? otherwise circuit board stacking may be needed.

Btw, with some additional PGA-114 (020) and PGA-132 (030) to PGA-206 adapter it could be used as a upgrade option for those CPUs too.

OT Found while searching:
a68k.de - Overclocking Amiga.pdf
« Last Edit: January 06, 2013, 08:26:47 AM by freqmax »
 

Offline danbeaver

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Re: Motorola 68060 FPGA replacement module (idea)
« Reply #1 on: January 06, 2013, 09:21:30 AM »
I read somewhere (possibly a NatAmi post) that the FPGA would do poorly at attempting an 68060, but works for a simpler design at a higher clock rate. See if you can track that down. Adapting it to pin-for-pin plug into a socket is another matter; Jens does a lot of work in this area and might know, although us talking to him about accelerators is like asking Einstein to show you how he derived E=MC2.
 

Offline freqmax

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #2 on: January 06, 2013, 09:32:09 AM »
Perhaps a boosted 030/040 core pretending to be 68060 might be as good from a software point of view?

It's mainly a compatibility and perfomance issue. It doesn't have to be 060 in its heart.
 

Offline danbeaver

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Re: Motorola 68060 FPGA replacement module (idea)
« Reply #3 on: January 06, 2013, 09:39:38 AM »
I think a 32-bit core (68020) running at 100Mhz is more likely, but then converted to silicon it might go even higher with less heat. Again, Jens would know.

There might be copyright issues by the way.
« Last Edit: January 06, 2013, 09:40:49 AM by danbeaver »
 

Offline freqmax

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #4 on: January 06, 2013, 10:55:36 AM »
You mean as in ASIC silicon? that would cost at least 40 000 USD, proberbly around 400 000 USD.

The function is not protected as the patents has expired. However perhaps the instruction set opcodes are? but I doubt that to as there exist many other projects in this area without legal problems.
 

Offline Hattig

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #5 on: January 06, 2013, 11:09:47 AM »
Quote from: freqmax;721422
You mean as in ASIC silicon? that would cost at least 40 000 USD, proberbly around 400 000 USD.

The function is not protected as the patents has expired. However perhaps the instruction set opcodes are? but I doubt that to as there exist many other projects in this area without legal problems.


I think he meant having an FPGA on the package. As you say, an ASIC would cost a lot, even if you went for one of the shared-ASIC projects to share the one-off costs with other ASIC designers.

But first, you'd need a design (be it a highly clocked '020 core, or an '060 clone, or the Natami '050/'070 design) that would run acceptably fast on that FPGA, and you'd also need to implement the I/O compatibility with the PGA-206 interface.
 

Offline Mrs Beanbag

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #6 on: January 06, 2013, 12:29:55 PM »
I suspect the biggest speed boost would come from full pipelining. I would guess the RAM could be fast enough relative to the FPGA for a data cache not to be that important, but an instruction cache might help. There are pipelined FPGA cores, MIPS of course being a prime example.

A RISC core with 680x0 programming model should be fairly easy, starting from for instance a MIPS core, then add a microcode engine. I mean if you know what you're doing. Which I don't, sadly.
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Offline Fats

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #7 on: January 06, 2013, 02:20:20 PM »
Quote from: freqmax;721403
But that a solution could be to join a male socket and a FPGA on top of that. Much like the 486- or pentium  overdrive solutions for the x86.


For DIL packages OHO Elektronik is already doing that with GODIL. I am not sure if they could be used as a M68000 replacement and how quick it could be. The memory on the board could probably be real fast RAM. The products are sold at trenz electronic.

I think somebody should make a similar board but replace the DIL connection with an A1200 trapdoor expansion connection. I would love that!

greets,
Staf.
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Offline ChaosLord

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #8 on: January 06, 2013, 02:50:37 PM »
Quote from: Mrs Beanbag;721428
I suspect the biggest speed boost would come from full pipelining. I would guess the RAM could be fast enough relative to the FPGA for a data cache not to be that important,

That is absolutely not the way it works.

Modern RAM is horrifically slow at randomly accessing memory.  So a datacache is tremendously important else the speed will be ridiculously slow.

The RAM manufacturers know this but they "just assume" that everyone is using an intel cpu with 4+MB of cache.

A copyback datacache is absolutely required for reasonable speed when using modern memory.
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Offline ChaosLord

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #9 on: January 06, 2013, 02:55:41 PM »
Quote
Motorola 68060 FPGA replacement module (idea)
Its waaaaaaaaaaaaay to hard to make the signals on the pins perfectly match a real 68060.

It is a better idea to just make the best 680x0 that you can make, using whatever pins you need and using whatever technology you can come up with.

I like the idea of an FPGA 68070 accellerator card.

I have been pushing the idea of a 2GB RAM + 680x0 accelerator card.

Having the CPU be in an FPGA means that we could update our CPUs each year as the core gets optimized.  To gain a little speed here and there.  It would r0x my sox!
Wanna try a wonderfull strategy game with lots of handdrawn anims,
Magic Spells and Monsters, Incredible playability and lastability,
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Offline Mrs Beanbag

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #10 on: January 06, 2013, 03:13:40 PM »
I forgot about RAM latency, but wouldn't RAM at 1333MHz and CL9 still be able to max out a 100MHz CPU?

Would there be any advantage to using graphics memory in this application? (i.e. GDDR4/5 rather than DDR2/3)
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Offline ChaosLord

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #11 on: January 06, 2013, 03:28:33 PM »
Quote from: Mrs Beanbag;721457
I forgot about RAM latency, but wouldn't RAM at 1333MHz and CL9 still be able to max out a 100MHz CPU?


There is absolutely no such thing as 1333Mhz RAM.

When they advertise that they are LYING.

There is absolutely no such thing as 1333Mhz RAM.

When confronted they will just lie about it... or if u find someone honest then they will admit that it is really only 1333 million transactions per second that can be attained only in a limited set of circumstances.

Mhz is an absolute that is always attained all of the time no matter what.

Transactions can only happen 1333 million times per second as along as a big complicated set of rules are followed.  One of the main rules is that all the memory accesses happen in a perfect line one after the other in perfect sequential order.  There are other rules too but they get way to complicated for me to explain here.

When u break that rule, as u often do, then your speed drops like a rock because there is no 1333Mhz RAM.

You also can't write individual bytes on modern RAM.  You have to write a giant block.  I forgot the blocksize on current RAM setups but its either 16 or 32 bytes.

This is why a large copyback cache is extremely important with modern RAM chips.
Wanna try a wonderfull strategy game with lots of handdrawn anims,
Magic Spells and Monsters, Incredible playability and lastability,
English speech, etc. Total Chaos AGA
 

Offline Mrs Beanbag

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #12 on: January 06, 2013, 03:37:00 PM »
Quote from: ChaosLord;721459
then your speed drops like a rock
Confusing metaphor :crazy: When you drop a rock, it just goes faster and faster!

Ok, well, I'll take your word for it. So even an implementation of a plain 68000 would need some sort of cache in this case.
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Offline freqmax

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #13 on: January 06, 2013, 03:46:51 PM »
Quote from: ChaosLord;721455
Its waaaaaaaaaaaaay to hard to make the signals on the pins perfectly match a real 68060.


Where is that stated as a requirement?
(it's only needed for A500 and A1200 setups where some software rely on hw specifics)

My original idea was to provide a solution for those that want FPGA Arcade (MikeJ) with add on board and want to make use of a fast 68060 CPU but just can't get one.

@ChaosLord, How can you be absolutely sure there's no 1333 MHz capable RAM ..? ;)
(but signal integrity will be a pain)
« Last Edit: January 06, 2013, 03:50:43 PM by freqmax »
 

Offline Mrs Beanbag

Re: Motorola 68060 FPGA replacement module (idea)
« Reply #14 on: January 06, 2013, 03:56:24 PM »
You know what I don't even care about 1333MHz RAM anymore, you can buy 8Mb chips of 16-bit SRAM:
http://uk.farnell.com/renesas/r1wv6416rbg-5si/sram-64mbit-3v-55ns-48fbga/dp/2068172
I guess that would be fast enough for an off-chip cache for an FPGA 68060 implementation, if not big enough for the main ram itself.

Maybe he will shoot this down for some other reason... but if I throw enough ideas at the wall maybe one of them will stick. Like a rock.
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