FPGA for dummies

[psxphill]

Likely related to the threeshold of the internal sense amplifiers. Ie before it reaches the thermal noise floor.

Yeah good luck with converting that 1:1 in an FPGA.

[psxphill]

You take the VHDL & it gets turned into an ASIC. I know how that works. Once you have the ASIC you run it when the clock starts. Running doesn't require a CPU style fetch execute mechanism, just a clock.
 
I understand whats going on physically in the FPGA and ASIC & it supports my argument about using an FPGA to recreate an Amiga is simulation/emulation.
 
I am not going to explain everything in minute detail, just so you can't find a way to purposefully misinterpret what I'm saying.
 
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it" Upton Sinclair.

[psxphill]

Okay, explain it then. What is involved in that translation between VHDL and an ASIC? If you know how it works, then it won't be a problem explaining it. I await your reply.

logic synthesis -> placement tool -> routing tool -> profit

[psxphill]

This is why saying an ASIC 'running' VHDL is a mistake, unless you're making some gross oversimplification that any description of an integrated circuit is a 'VHDL'.

You're suprised at gross oversimplification on an internet message board? While trivial in comparison I also don't mention creating a bitstream from VHDL and loading that into an FPGA.
 
The discussion was about whether using VHDL that described the behaviour of an Amiga to build an FPGA or an ASIC was simulation/emulation, the procedures you go through to do that are irrelevant to that discussion.
 
In the same way as how you simulate the amiga chipset is irrelevant, whether you're using software, hardware or pen & paper (this last one is labour intensive, slow & suffers from random innaccuracies and boredom).

[psxphill]

Before you start on the 'so FPGAs are only emulations' schtick, the important point to note is that even though the designs are different, they can be functionally identical. Think about it like this, Sony brings out a TV using an FPGA to drive the circuitry. They then bring out a new model, which is the same as the old one in every way, except the FPGA is replaced with an ASIC. Is the later model an emulation of the first? No.

If you design one circuit to work the same as another one then it is a simulation. When the company that made the original uses the same design but slightly modifies it (i.e. switches from an FPGA to an ASIC) then it's not.
 
The same way that IBM made IBM PC's and other companies produced IBM PC clones. The term clone doesn't refer to the circuit being a direct copy, only that the same software can run. In todays language it would be an emulation.
 
The expansion model no 1 is also simulation/emulation.
 
http://www.colecovision.dk/atari.htm

[psxphill]

Emulation has a specific meaning when it comes to computers, it means making one computer run programs from an incompatible one. Copying, on the other hand, is prevalent throughout computing. For example, if I copy a file (i.e. clone it), am I emulating the file? I'm sorry, but your definitions are not standing up to scrutiny.

It's behaviour you emulate. So daemon tools is a dvd drive emulator.
Or you can have an ISA card: http://www.flickr.com/photos/defor/sets/72157623805154726/
 
Emulation doesn't just refer to software that makes a computer behave like another. However much you wish it did.
The term emulation started out purely as using hardware, using software was considered simulation (probably because you couldn't achieve real time results with software).
 
IBM PC's and clones share some chips, but the circuit board is different. It was only really the processors that were shared, the rest that makes it a clone was the same memory map etc. Before nvidia/ati/s3 etc you had custom graphics cards that emulated only certain functionality of IBM's original chips. Most graphics chips these days only emulate enough of VGA for the BIOS and windows boot screen & the days are numbered for that. Windows 7 uses a VESA mode (1024x768 IIRC) on bootup instead of Mode-X.
 
The term clone is similar to emulation in that IBM never made any clones, even though they made loads of different PC's. The clones were just as different to each other as they were to IBM's designs.

[psxphill]

The same is true of the term 'emulation'. It now has a specific meaning when it comes to computing. See for yourself:
http://dictionary.reference.com/browse/emulate

You better explain that to everyone else that disagrees with you.
 
from http://en.wiktionary.org/wiki/emulate
(computing) of a program or device to imitate another program or device
 
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4556828
http://www.syntiac.com/fpga64.html
http://dl.acm.org/citation.cfm?id=1999455
http://www.linkedin.com/in/mattdipaolo
http://arstechnica.com/civis/viewtopic.php?f=2&t=1152634&start=40
http://www.patentgenius.com/patent/6965972.html
http://www.scene.org/showforum.php?forum=11&topic=173109
 
The "emulator in an fpga is not emulation" stance seems limited to a few commercial "emulator in an fpga" projects.

[psxphill]

Be careful not to become to exacting in your definition of what is real, since many companies will use chips from different sources from one month to the next.
So two computers made by the same manufacturer, a few months apart, in the same factory may not be identical, but does that mean that one is emulating the other?

Generally chips from different sources are made from the same mask and are just second source suppliers. AMD was a second source of Intel parts before it decided to make it's own. Therefore any variance in the components should be similar to the variance in the parts from the original supplier. It's impossible to make something identical, which is how you can get different speed rated processors out of the same batch.
 
This is different to starting over and designing your own motherboard.
 
I agree that it seems vague because of the same company clause, but you can't emulate yourself & it would muddy the use of the term if you could. It is better than the "emulator in an fpga is not emulation" argument that causes more confusion (although that confusion will produce higher profits, so it's easy to see why it's done).

[psxphill]

Generally chips from different sources are made from the same mask and are just second source suppliers.

I don't know if that's true at all, but I do know that it's not generally true.

Well that was true for processors by Intel & Motorola.
 
For other chips there are standards that are specific enough that you shouldn't have problems, but yes problems do occur.
 
But then emulation is never exact either.

[psxphill]

Yes, I quite agree, after sorting out the fools who like to show off, those speaking about what they know were most enlightening. I didn't even know there was such a technology as FPGA before this thread. Fascinating, a volatile circuit configuration chip! What RAM is to data, FPGAs are to circuitry (or what CD-Rs are to data, in some cases).

The fools who like to show off by making stupid straw man statements in a vain attempt to defend the "emulator in an fpga is not an emulator" stance have managed to make you think that an fpga works differently to how it does.
 
An fpga is made up of programmable cells, similar in concept to an ALU. http://en.wikipedia.org/wiki/Arithmetic_logic_unit
The routing between the cells is configurable by turning pre-existing routes on and off. The circuit never gets changes, gates only get turned on and off that change the routing and the operation of the cell.
 
An FPGA is an evolution of the PLA. http://en.wikipedia.org/wiki/Programmable_Array_Logic

[psxphill]

Do you work in the industry? Curious to know how you know this.

It's very well known.
 
http://en.wikipedia.org/wiki/Am286
 
Intel sued AMD for their 386.
 
http://en.wikipedia.org/wiki/Second_source
 
The 68000 was second sourced by alot of companies, Mostek, Rockwell, Signetics, Thomson & Toshiba.
 
http://en.wikipedia.org/wiki/Motorola_68000#Second-sourcing
 
The fools thing was aimed at the "my room lamp emulates light". It's even a rubbish analogy, because the lamp emits light. You could suggest that a lamp simulates the sun, however it would be a very innaccurate simulation as a lamp and the sun don't share many simularities & the lamp wasn't based on properties of the sun. An electronic lamp was built to replace gas lamps, but even then the light given out is completely different. But I'm sure it sounded funny when it was posted, even though it's just a stupid straw man argument.
 
The term "Emulator" has been used to refer to hardware simulated by FPGA/earlier similar technologies for two decades, it's not a relatively new technology.
 
You could say that a software emulator recreates a computer system, so because the FPGA 64 says that it's an emulator in an fpga and it recreates the c64 doesn't change anything.

[psxphill]

I'm sure the FPGA emulation magicians here are doing a great job by making qualified and well-informed design guesses based on information that exists about these chips, and black box testing them with the original chips, but I doubt they are making exact copies of them at a gate level.

Yes, the logic isn't the same. It is emulation.
 
Even though the FPGA's have extra functionality, they can still emulate the old functionality enough to run the old software.
 
Like it or not, it's emulation. Nothing about the word emulate implies using a computer. It means one thing trying to behave like another thing.

[psxphill]

No, it isn't emulation.

What do you think emulation is?

[psxphill]

So does that mean AGA chipset emulates ECS and ECS emulates OCS ?

Definitely for AGA vs ECS, apart from the blitter it was basically a new implementation.
 
AGA & AAA don't emulate ECS all that well either. The weird super hires mode palette is different in ECS to all the other implementations, which is why when ECS came out Commodore were telling people to use the OS or else. They only claimed compatibility for hardware hitting programmes that used OCS features. Commodore went so far as to not even release documentation on AGA registers, as AAA didn't emulate those either.
 

It was a rhetorical question

It's not a good example of a rhetorical question, it came over as a strawman. However I don't think you expected anyone to disagree with you.

[psxphill]

All right... So, only the very first Amiga prototype which successfully ran some software is the original. All other Amigas 1000, 500, 2000, 600, 1200.. etc ever produced are emulators.

They aren't emulators, they are computers that have have components that emulate others. Some old sound cards had soundblaster emulation, that doesn't mean that the computer you put it inside was just an emulator.
 

and we can stop this stupid discussion about emulation that pops up every now and then. Hopefully it will let people enjoy new FPGA hardware without obnoxious comments.

Discussing whether it's an emulator or not is not obnoxious. Even the "I don't like emulation but I like fpga's, therefore an fpga can't be emulation" standpoint isn't obnoxious.
 
A 68060 and PPC in an FPGA for the A1200 would be awesome.

[psxphill]

Regardless of whether you are right or not, and whatever the definition of an emulator might be, whenever someone feels excited about new FPGA stuff here comes one of the "captain technicalities" and drags on about it not being a real hardware implementation but only an emulation. It is damn right annoying and obnoxious.
 
If someone had a hand drawing of a computer and called it his Amiga I would support him, and not lecture him about that not being a real computer.
 
Be positive and supportive.

I'm not sure where to go with that, I don't think I'd be excited if I ordered an FPGA arcade and a hand drawn picture turned up. Patronising people doesn't help them.
 
The FPGA arcade isn't an Amiga, it can emulate lots of different computers/consoles.
 
You only consider it dragging it down because you are being unsupportive and negative about emulators.
 
And yes, people emulate others.
 
em·u·late  
/ˈemyəˌlāt/

Verb

• Match or surpass (a person or achievement), typically by imitation.
• Imitate.