FPGA for dummies

[Fats]

The FPGA isn't a 68K chip, it's emulating one.  A different FPGA emulates the custom chips.  Amiga OS runs on top of this emulated hardware.  UAE emulates a 68K in a program, this same program emulates the custom chips.  Amiga OS runs on top of this emulated hardware.

And an A4000 is an emulation of a A1000 with some extensions added
Staf.

[Fats]

And there we have it: Lookup tables. This means there's no physical chip, which means it's an emulation (imitation). Or perhaps it's about the meaning of the word 'emulation' being interpreted in different ways.

Now some more philosophical questions.

By your definition most of the routing on the internet is done through emulation; or does one think Xilinx makes >$1k FPGAs for the hobbyists around here ?
Given that most of these designs will never be put in an ASIC what are they then actually emulating ?

Most of PCB designs are often done first with some parts done in programmable hardware and then later when it is really succesful a cost reduced version is made with the programmable part replaced with an ASIC. This means that an ASIC is emulation.

I am looking forward to the discussion ...

greets,
Staf.

PS: I think there is an all explaining theory which doesn't conflict with anybody's view here. Try to find it !

[Fats]

Given that most of these designs will never be put in an ASIC what are they then actually emulating ?

Devices that don't exist completely physically.

I have to admit you have some weird definition of emulation. And I can only agree with your definition if you also consider MS Word running in Windows a simulation of a (virtual) fully mechanical machine doing the same thing.
I think this is the base of the misunderstanding. You claim that soft-wired circuits == emulation, hard-wired circuits == no emulation.
So then you also have to claim software == simulation, hardware == no simulation.
I, and probably most people, would claim that hard-wired circuits can still be emulation of another device, e.g, the C64 in a joystick of Jeri Ellsworth, and soft-wired circuits can be unique designs not emulating anything. Hardwired/programmable devices are just two terms orthogonal to emulation/no emulation.

greets,
Staf.

[Fats]

With the few people in this thread that understand FPGA's better than the average bear, this is a good place to ask what the differences are between FPGA's and the XMOS programmable chips.

I follow EE Journal they often discuss newest development in ASIC, FPGA and embedded. They have also an article on XMOS from a year or two ago here.

greets,
Staf.

[Fats]

Saying that you won't get this particular problem proves my point that what you doing with an FPGA is emulation.

Are you claiming using an FPGA is always emulation ?
Is an FPGA based Cisco router emulation then ? What are they emulating, are you also in the league that says this is emulating a fictional hardware implementation that never will be manufactured ?

greets,
Staf.

[Fats]

Seeing how I've become interested in FPGA computing, I would like to play with this, and seeing how a switch (emulated relay using bits as signals) emulator on a computer shouldn't be too hard to write, I would like to know how easy or difficult such virtual circuitry would be to translate to actual circuitry that can be implemented using an FPGA (or with wires and transistors, or an ASIC, or...)?

Once you have a logic description of your circuit, e.g. your switch emulator, there are automated tools that will convert it to something you can give to your FPGA or put it in ASIC. These tools or often free for some FPGAs and will cost up to a few $1k for making ASICs on advanced technology nodes.  Look on web for 'boolean logic',  'logic synthesis' and EDA.

BTW, a transistor is actually a switch and in CMOS technology you basically have two types: a nMOS one that is open when input is high and a pMOS one that is closed when input is high. It depends on convention if high is representing a 1 or a 0.
These transistors (e.g switches) can also be used in regimes where it is not fully on or off and this is often called analog behavior (amplifiers, current mirrors, ...).
Look on the web for transistor.

greets,
Staf.

[Fats]

Whether or not you feel the result is emulation or not i don't feel like participating in again, though i do have my choice on that debate.

Nice thing about language is that it is not an exact science; even dictionaries are just a snap shot of the what a word means at a certain point in time. So you can claim all people in this thread are right, as well as they are all wrong . I just love reading these threads and they can go on forever...

All the best!