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From: glen herrmannsfeldt on 22 Mar 2010 14:27
In comp.arch.fpga Jim Stewart <jstewart(a)jkmicro.com> wrote:
(snip)

> After I'm retired I hope. A well drawn schematic is a
> thing of beauty, helping techs to troubleshoot and
> customers to understand a product.

But some things just get too big to do that way. Would you
really like to see the schemtic for the Itanium chip?

> You could also ask when mechanical engineers will stop
> using fab drawings and just send the data as G codes.

There is the story about the design of the Boeing 777, all done
on computers. When the designers saw the actual airplane, they
were surprised by how big it was. They had been looking at it all
those years on computer monitors. I suppose in previous designs,
that parts would be constructed along the way, looked at by
designers, and changed as needed. That may have been done much
less in the case of the 777.

-- glen
From: Petter Gustad on 22 Mar 2010 17:40
glen herrmannsfeldt <gah(a)ugcs.caltech.edu> writes:

> Some time ago, I was wondering about using Verilog for PC board design.

I'm pretty bad when it comes to drawing schematics for PCB's as that
was never my primary job. I have also played with the idea of using an
HDL or even EDIF as I can write some neat Common Lisp software to
throw s-expressions around.

The big problem is not to create the netlist, but to interface it to
the parts database and the back-end tools which is usually
proprietary. One possibility would be to use gEDA or similar open
source PCB tools for the back-end work.

Petter

--
..sig removed by request.
From: Jonathan Bromley on 22 Mar 2010 19:27
On Mon, 22 Mar 2010 20:38:42 +0000, Peter wrote:

>Towards the end of my era of doing complicated logic designs, a very
>nice product was from somebody like Altera. It was a FREE VHDL
>compiler, crippled to work with just a few low end devices e.g. a
>22V10.

Cypress WARP, maybe? I designed a good few PAL/GAL
devices with it. There was a cut-off-at-the-knees
version of the Veribest VHDL simulator, too -
can't remember who shipped that. I still have a
copy on my machine, but I can't get it to run under XP.
--
Jonathan Bromley
From: Gerhard Hoffmann on 23 Mar 2010 19:47
rickman wrote:
> On Mar 22, 1:46 pm, Jim Stewart <jstew...(a)jkmicro.com> wrote:
>> rickman wrote:
>>
>> snip..
>>
>>> I wonder how long it will be before we give up on schematics
>>> altogether and just write pin lists or net lists?
>> After I'm retired I hope. A well drawn schematic is a
>> thing of beauty, helping techs to troubleshoot and
>> customers to understand a product.
>>
>> You could also ask when mechanical engineers will stop
>> using fab drawings and just send the data as G codes.
>
> I guess if you have an analog design with a lot of small components a
> schematic is good, but for many digital designs there is almost no
> point. Look inside any number of modern products and you see one, two
> or three large IC packages with lots of traces between them and few
> smaller components. The schematics for these products are horrendous,
> often much less clear than a simple pin list. Its not that they were
> drawn badly, but that it is impossible to draw a 300+ pin part with
> much utility. Even by breaking the part into sections it still ends
> up being a pin list with a box around it.
>
> I'll grant that analog designs can gain from schematic, but many of
> the digital ones are pointless when drawn.

I recently played with the Altium Designer, seems to be quite OK, and I
exported a low noise amplifier in VHDL for the fun of it:

entity MAT02 is port (
base: inout something;
emitter: inout something;
collector: inout something
);
end entity MAT02;
............

q1: mat02 port map (
base => input,
emitter => tail_current_source,
collector => left_c
)

was quite pointless for an analog design. But then you can spice that amplifier,
at least from the original circuit.

(cited from memory under influence of some nice Rioja :-) )


OTOH you can easily bridge the gap between a Xilinx user constraint file and
the things on the board that are connected to the FPGA. I like it. Maybe I'll buy it.


Gerhard



From: Gerhard Hoffmann on 24 Mar 2010 17:34
Peter wrote:

> That was another unfortunate product - their windoze version could not
> properly import DOS Orcad schematics (really clever).

DOS Orcad was a great improvement on its successors.
(with kind regards to Tony Hoare)


>> We ran 4 Compaq '286s overnight to possibly get a working 30[249]0 the next morning.
>
> What is that?

XC-3020, 3040, 3090. (regular expressions)

Ooops, wasn't that a 3042, really?

Gerhard
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