FPGA for dummies

[HenryCase]

If you design one circuit to work the same as another one then it is a simulation.

So, in your opinion, in the Sony TV example I gave, the ASIC is a simulation of an FPGA? If so, then I put it to you that nearly every ASIC that has ever existed is a simulation. Heck, Amigas are just simulations of Lorraine. Who knew we were all using simulations after all!

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.

Ah, I see, you realised you'd gone too far, so stuck in this caveat about it needing to be made by the original company. You're clutching at straws, seriously. Let's put it like this. Imagine Commodore went bankrupt after the A3000, and was bought by Atari. Atari then bring out a new Amiga model, the A1200. Does that now make the A1200 a simulation, whereas it wouldn't be if Commodore released it? I should point out that in this hypothetical situation, the Atari A1200 is absolutely identical to the Commodore A1200 we know today, apart from the company that made it.

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.

Your use of the term 'emulation' is very wooly. The only major difference between an IBM clone and an IBM PC is the company that assembles it. IBM don't make PCs any more, but if they did, think about this... IBM brings out a new desktop PC. I then build a PC for myself that uses the EXACT SAME PARTS as the IBM one. Is my computer emulating/simulating the IBM one?

I think where you're going wrong is that you're trying to stretch the term 'emulation' to encompass the term 'copy'. When it comes to computers, copying something is not the same as emulating something. 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.

[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.

[Thorham]

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).

In fact, the words 'to emulate' and 'emulation' have been in use since the 1500s! See these definitions from Merriam-Webster:

Emulate: http://www.merriam-webster.com/dictionary/emulate
Emulation: http://www.merriam-webster.com/dictionary/emulation

It's precisely this that makes it hard to tell what is and is not an emulation.

[HenryCase]

Emulation doesn't just refer to software that makes a computer behave like another. However much you wish it did.

That's where you're wrong. As language evolves, words pick up new meanings for specific contexts. For example, with computing, you have a bunch of words that existed before modern computing, but that have specific meanings when applied to computers: kernel, shell, mouse, pipe, etc...

Furthermore, as usage of the word changes, so too does our definition for it. For example, call someone a 'cynic' today and you have a certain image of a bitter, morose person, whereas the original meaning is almost spiritual in origin (See for yourself: http://en.wikipedia.org/wiki/Cynicism ). However, if you called someone a cynic today, you are unlikely to be referring to their wish to "live in agreement with Nature.".

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

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.

You missed my point. I was talking about a hypothetical situation where all the components were identical, and it was only the company assembling the devices that changed. It's perfectly possible to build a PC that matches an IBM design exactly, my question was, is it a clone purely because of the company that put it together? To my mind, it's the device itself which is of interest, the company that makes it is not of any great importance.

[A6000]

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?

[HenryCase]

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?

A6000, psxphill is arguing that it doesn't matter that the designs are different, as long as they come from the same company. IMO bringing the role of companies into this is a red herring, as we're talking about how technology is identified, not the manufacturers of that technology, but that's what is being proposed.

[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).

[billt]

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.

Some companies get bit by part changes. Supposedly identical parts from different suppliers can have enough difference to cause a product defect (probably a new timing or crosstalk issue due to faster/stronger outputs). Sometimes a single supplier changes their chip and this can cause a defect, without any notice or updates to documentation. One can be left scratching his head for quite a while until a chip change becomes known.

Also understand that even the same mask set in a different factory can give a different result and break timing or crosstalk.

[JimS]

That's where you're wrong. As language evolves, words pick up new meanings for specific contexts. For example, with computing, you have a bunch of words that existed before modern computing, but that have specific meanings when applied to computers: kernel, shell, mouse, pipe, etc...

Not only that, but the word "computer" had a meaning before the electronic device was invented. It originally referred to a person who had the fun task of calculating by hand huge and tedious tables of math functions. (Sin Cos and such)

[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.

[Mizar]

Sorry, I seem to be behind in reading this informative, fascinating, foolish, and ludicrous, massive thread.  The above adjectives applying in a non mutually exclusive fashion, depending who is speaking.

If I made a parallel switch emulator, where you have two kinds of switches (normal and inverted), that behave like relays and have four pins, then how difficult would it be to translate such virtual circuitry to FPGA circuitry?

The emulation doesn't emulate electricity and simply uses 0 and 1 as signals, and signals are never amplified in any way.

The only emulation being attempted here is to speak techno babble, while lacking any fundamental understanding of the principles or technology being spoken of.

My roof lamp emulates light..

:roflmao:  No kidding, that's how much sense he/she was making!

Very informative thread once a guy sorts out the arguing and dick waving, hehe.

Didn't know a heck of a lot about FPGA implementations before this read.

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).  And it makes sense, having played around with manually configurable Radio Shack circuit kits when was a lad, and knowing the fundamental function of electronic components (particularly transistors), that this could be done.

[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

[HenryCase]

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.

First of all, some of those examples weren't related to computing, as I said before the term emulation has specific meaning in computing, this does not need to extend to the whole electronics industry.

Secondly, FPGA re-implementations of entire computing platforms is a relatively new phenomenon, so it's not surprising that people would use the closest word they could think of to describe them.

Thirdly, some of the content you linked to uses other, more descriptive, terms to describe what's occurring, e.g. "FPGA-64 is a re-implementation of the Commodore-64 computer using reconfigurable logic chips." Re-implementation is a clearer way of describing the process being followed.

Well that was true for processors by Intel & Motorola.

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

The fools who like to show off

So someone who disagrees with you is a fool who likes to show off. Hmm... I didn't call you a fool, I would expect the same in return.

[HenryCase]

Not only that, but the word "computer" had a meaning before the electronic device was invented. It originally referred to a person who had the fun task of calculating by hand huge and tedious tables of math functions. (Sin Cos and such)

Quite right. This is the description of computer that existed at the time of Turing, in his work (and the work of other computing pioneers) he used this earlier definition to convey what was being proposed.

[Thorham]

The only emulation being attempted here is to speak techno babble, while lacking any fundamental understanding of the principles or technology being spoken of.

That QUESTION isn't such an attempt, it's a QUESTION. I've actually written that in this thread already. Yes, this thread has caused me to get interested in this kind of thing, and I was wondering how hard/easy switch based logic is to convert to some FPGA format.

:roflmao:  No kidding, that's how much sense he/she was making!

Dude, you're laughing at a BS reply to my question

Yes, I quite agree, after sorting out the fools who like to show off

I guess I do have to say I was wrong again It's NOT about showing off. I was trying to argue a serious point here, which is something that way too many people didn't understand (which is understandable). My mistake was trying to use technical terms to help make my point, and obviously that didn't work.

What I want to know is how many times I still have to say I was wrong?