FPGA Central

Trying to design an FPGA from scratch, but not sure how this fpga
should be programmed. It is going to be a tile concept fpga with a LUT
SRAM architecture.

I have the resources to write VHDL/Verilog, netlist it and do the
layout(incl. routing), but how do I program this fpga? I guess this is
something I am not too clear about. Thanks folks

<[email protected]> wrote in message
news:[email protected]...
>
> I have the resources to write VHDL/Verilog, netlist it and do the
> layout(incl. routing), but how do I program this fpga?
>

Very carefully!

Go and do some reading. My advice is to start with the website of the FPGA
vendor you've chosen. Alternatively, as you seem to work for Intel, get them
to send you on an expensive course.

HTH, Syms.

p.s. http://catb.org/~esr/faqs/smart-questions.html

>I have the resources to write VHDL/Verilog, netlist it and do the
>layout(incl. routing), but how do I program this fpga? I guess this is
>something I am not too clear about. Thanks folks

Look in the data sheet. There will be a section on that area, maybe
called Configuration.

The compiler will give you a pile of bits. Typically, you feed them
serially to the FPGA with clock and data pins. You can bit bang it from
a small CPU. In a different mode, the FPGA can probably wiggle the
clock to load itself from a serial ROM. (Then you have to program the ROM.)

You can usually load them via JTAG.

The vendor probably provides a tool to do it.

It's probably simplest to get one of the low cost starter kits
and follow the directions for one of their demos. Or just
read their documention to see how it's done.

--
These are my opinions, not necessarily my employer's. I hate spam.

Thanks for the responses, but I think I need to be more clear on my
question. First off, this is for a class project for my advanced
degree, so my employer has nothing to do with it.

When I mean design an FPGA, I literally mean designing it. Not
programming a vendor's FPGA.

So going back to my original question, if I did design an FPGA with
LUTs and SRAM, how can I program this FPGA to do a particular
function? Do I write the software? If so, is that an easy thing to do?

Are there any tools available that would let me program any FPGA? I
looked at DAGGER, but seems like it needs an input file from the VPACK
tool. thanks again.

[email protected] wrote:
> Thanks for the responses, but I think I need to be more clear on my
> question. First off, this is for a class project for my advanced
> degree, so my employer has nothing to do with it.
>
> When I mean design an FPGA, I literally mean designing it. Not
> programming a vendor's FPGA.
>
> So going back to my original question, if I did design an FPGA with
> LUTs and SRAM, how can I program this FPGA to do a particular
> function? Do I write the software? If so, is that an easy thing to do?
>
> Are there any tools available that would let me program any FPGA? I
> looked at DAGGER, but seems like it needs an input file from the VPACK
> tool. thanks again.

I think you still need to explain yourself more. Are you creating a
design of your own custom FPGA (that other people could theoretically
program) for a class project? Are you planning to actually fab a chip
through some university program like MOSIS? That seems like an pretty
ambitious class project.

When you say software to program the FPGA are you talking about
something to download the bitstream? Or are you talking about the
complete HDL synthesis and place and route tool chain?

-Jeff

On Tue, 1 Jul 2008 19:01:28 -0700 (PDT), [email protected] wrote:

>Thanks for the responses, but I think I need to be more clear on my
>question. First off, this is for a class project for my advanced
>degree, so my employer has nothing to do with it.
>
>When I mean design an FPGA, I literally mean designing it. Not
>programming a vendor's FPGA.
>
>So going back to my original question, if I did design an FPGA with
>LUTs and SRAM, how can I program this FPGA to do a particular
>function? Do I write the software? If so, is that an easy thing to do?
>
>Are there any tools available that would let me program any FPGA? I
>looked at DAGGER, but seems like it needs an input file from the VPACK
>tool. thanks again.

You have to also design the programming architecture into your FPGA.
FPGAs are basically SRAM (LUTs are SRAM too), configurable DFF cells
and a whole lot of wires with switches on each end. The SRAM blocks
and DFFs (assuming you don't have any other hard macros ala
multipliers etc) have their inputs and outputs connected to some
switches which are connected to the wires too. So you connect all the
control inputs of the switches to some regular DFFs which are
connected in a scan chain type connection themselves and when you
generate the programming file, you shift it in upon which you
configure all the switches and the configuration options of your DFFs.
If you also want to initialize your SRAM blocks you can design
configuration time memory controllers which write the shifted value
into them to the SRAM.

If you're doing any non-trivial FPGA design, I think you'll find that
generating the actual programming file itself from your logic design
specification is one of the most time consuming tasks.

On Jul 1, 7:01*pm, phxag...@gmail.com wrote:
> Thanks for the responses, but I think I need to be more clear on my
> question. First off, this is for a class project for my advanced
> degree, so my employer has nothing to do with it.
>
> When I mean design an FPGA, I literally mean designing it. Not
> programming a vendor's FPGA.

This sounds rather involved for a class project. And more of an
exercise in CAD tools than anything else.

> So going back to my original question, if I did design an FPGA with
> LUTs and SRAM, how can I program this FPGA to do a particular
> function? Do I write the software? If so, is that an easy thing to do?

I'm not sure what you're getting at here. What do you mean by
"program", exactly? Putting the bitfile into the FPGA? Generating the
bitfile from a placed/routed design?

> Are there any tools available that would let me program any FPGA? I
> looked at DAGGER, but seems like it needs an input file from the VPACK
> tool. thanks again.

You might be able to modify DAGGER to do what you want. But this might
be a good time to take a step back and figure out 1) what exactly you
want to achieve with your project, 2) what requisite knowledge you
have yet to acquire, 3) whether it's doable in the timeframe
specified.

Cheers,
Mike

On Jul 1, 9:28*pm, mng <michael.jh...@gmail.com> wrote:
> On Jul 1, 7:01*pm, phxag...@gmail.com wrote:
>
> > Thanks for the responses, but I think I need to be more clear on my
> > question. First off, this is for a class project for my advanced
> > degree, so my employer has nothing to do with it.
>
> > When I mean design an FPGA, I literally mean designing it. Not
> > programming a vendor's FPGA.
>
> This sounds rather involved for a class project. And more of an
> exercise in CAD tools than anything else.
>
> > So going back to my original question, if I did design an FPGA with
> > LUTs and SRAM, how can I program this FPGA to do a particular
> > function? Do I write the software? If so, is that an easy thing to do?
>
> I'm not sure what you're getting at here. What do you mean by
> "program", exactly? Putting the bitfile into the FPGA? Generating the
> bitfile from a placed/routed design?
>
> > Are there any tools available that would let me program any FPGA? I
> > looked at DAGGER, but seems like it needs an input file from the VPACK
> > tool. thanks again.
>
> You might be able to modify DAGGER to do what you want. But this might
> be a good time to take a step back and figure out 1) what exactly you
> want to achieve with your project, 2) what requisite knowledge you
> have yet to acquire, 3) whether it's doable in the timeframe
> specified.
>
> Cheers,
> Mike

I think we all wonder what you want to achieve with your project.
You could re-invent and re-implement what Xilinx did 25 years ago, but
what would that do for you, or for anybody?
It's hard to help you when you leave so many things un-explained.
Peter Alfke

[email protected] wrote:
> Thanks for the responses, but I think I need to be more clear on my
> question. First off, this is for a class project for my advanced
> degree, so my employer has nothing to do with it.
>
> When I mean design an FPGA, I literally mean designing it. Not
> programming a vendor's FPGA.
>
> So going back to my original question, if I did design an FPGA with
> LUTs and SRAM, how can I program this FPGA to do a particular
> function?

You set the config bits, typically serially loaded.

> Do I write the software?

Yes

> If so, is that an easy thing to do?

No.

>
> Are there any tools available that would let me program any FPGA? I
> looked at DAGGER, but seems like it needs an input file from the VPACK
> tool. thanks again.

What does your Professor want ?

How many hours are allocated to this ?

Does he want working silicon (!), or a simulated result ?

How will your FPGA vary fom the 'mainstream' ones, and what
aspect of that difference do you need to demonstrate ?

How large does this need to be ?


-jg

On 2008-07-02, [email protected] <[email protected]> wrote:
>
> So going back to my original question, if I did design an FPGA with
> LUTs and SRAM, how can I program this FPGA to do a particular
> function? Do I write the software? If so, is that an easy thing to do?

For proof-of-concept you should be able to generate a bitstream that hooks
a few gates to a flop from inputs to outputs. Since you designed the FPGA,
you'd know how to do that.

If you want to generate that from a high-level description there will be
significant software involved. You may be able to take a frontend like
Icarus Verilog and write a new backend for your project, but it will take
considerable software expertise.

--
Ben Jackson AD7GD
<[email protected]>
http://www.ben.com/

Thank you all for your inputs on this subject. You are right, I would
first want to evaluate what I am signing-up for and thats exactly what
I am doing in this group It would definitely not go all the way
into fabrication, but a proof of concept would be good enough. The
idea is to create a novel tile architecture that does not exist
today.

Question for Mike. I thought Dagger was a web-based tool. Can I really
modify it?

On Jul 1, 11:31*pm, phxag...@gmail.com wrote:
> Thank you all for your inputs on this subject. You are right, I would
> first want to evaluate what I am signing-up for and thats exactly what
> I am doing in this group It would definitely not go all the way
> into fabrication, but a proof of concept would be good enough. The
> idea is to create a novel tile architecture that does not exist
> today.
>
> Question for Mike. I thought Dagger was a web-based tool. Can I really
> modify it?

I just did a search, skimmed a poster and a user's manual, so I don't
know very much about it. The thing is, if you're in academic research,
you can ask the people who developed Dagger for their source code, and
they'll probably be happy to share it with you. That's the way it
usually works.

But really, what sort of class inspires such a complicated project?

Cheers,
Mike