Anyone use HDL as design tool for PCBs?

Hi,
   Does anyone out there in usenet-land know of tools to let you design
Printed Circuit Boards with VHDL? I'm ready to switch from schematic entry,
I want portability! (And all the other good reasons I switched from
schematic entry for my FPGA designs) Anyone use a PCB layout tool that
accepts EDIF files? I see there are translator tools. Anyone ready to share
their experiences, pitfalls et cetera?
        thanks for reading, Syms.

On Tue, 18 Nov 2003 17:49:24 -0800, "Symon" <symon_brewer@hotmail.com>
wrote:

>Hi,
>   Does anyone out there in usenet-land know of tools to let you design
>Printed Circuit Boards with VHDL? I'm ready to switch from schematic entry,
>I want portability! (And all the other good reasons I switched from
>schematic entry for my FPGA designs) Anyone use a PCB layout tool that
>accepts EDIF files? I see there are translator tools. Anyone ready to share
>their experiences, pitfalls et cetera?

Features like pin swapping, gate swapping and cross probing will only
work with a tightly integrated pcb and "source" toolset.

I suspect you would lose this with an HDL front end, although they do
seem possible in theory.


Frankly, the thought of designing a switchmode power supply using an
HDL scares me.  Designing a microstrip filter using an HDL seems nigh
on impossible.
(Hint: both these applications require careful layout, which is
something that can be more easily expressed with a graphical entry
tool.)

Regards,
Allan.

Hi Allan,

I tend to agree with your opinions. I just wanted to add that PCB layout
tools that generate VHDL/Verilog netlists are very useful for system level
simulation. Obviously this is not the information the original post was
attempting to obtain but I wanted to throw it out there for others to
contemplate.

Matt


"Allan Herriman" <allan.herriman.hates.spam@ctam.com.au.invalid> wrote in
message news:o0plrvk7kvd3mm2evhd0fr6nd1kdu26d3e@4ax.com...
> On Tue, 18 Nov 2003 17:49:24 -0800, "Symon" <symon_brewer@hotmail.com>
> wrote:
>
> >Hi,
> >   Does anyone out there in usenet-land know of tools to let you design
> >Printed Circuit Boards with VHDL? I'm ready to switch from schematic
entry,
> >I want portability! (And all the other good reasons I switched from
> >schematic entry for my FPGA designs) Anyone use a PCB layout tool that
> >accepts EDIF files? I see there are translator tools. Anyone ready to
share
> >their experiences, pitfalls et cetera?
>
> Features like pin swapping, gate swapping and cross probing will only
> work with a tightly integrated pcb and "source" toolset.
>
> I suspect you would lose this with an HDL front end, although they do
> seem possible in theory.
>
>
> Frankly, the thought of designing a switchmode power supply using an
> HDL scares me.  Designing a microstrip filter using an HDL seems nigh
> on impossible.
> (Hint: both these applications require careful layout, which is
> something that can be more easily expressed with a graphical entry
> tool.)
>
> Regards,
> Allan.

I was always considering VHDL as behaviur/logic (netlist on functional
gates) specification language. There are no means to add more detales
required at PCB layout abstraction layer. VHDL has no means to describe
placement, traces and device packages. I'm I missing missing something?

"Valentin Tihomirov" <valentin@abelectron.com> wrote in message
news:bpfn15$1nv2n7$1@ID-212430.news.uni-berlin.de...
> I was always considering VHDL as behaviur/logic (netlist on functional
> gates) specification language. There are no means to add more detales
> required at PCB layout abstraction layer. VHDL has no means to describe
> placement, traces and device packages. I'm I missing missing something?

In principle, all this information could be stored in VHDL
attributes.  Attributes were designed for precisely this reason -
attaching information to a VHDL object that makes no sense in
VHDL, but must be passed to other tools.  In practice, however,
the result would be a disgusting mess.

Stick with a decent schematic package that can generate
a VHDL netlist.  Use that VHDL netlist for your pre-layout
functional simulations, and use the conventional
schematic-to-PCB tools for layout.
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * Perl * Tcl/Tk * Verification * Project Services

Doulos Ltd. Church Hatch, 22 Market Place, Ringwood, Hampshire, BH24 1AW, UK
Tel: +44 (0)1425 471223                    mail: jonathan.bromley@doulos.com
Fax: +44 (0)1425 471573                           Web: http://www.doulos.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

Matt wrote:

> I tend to agree with your opinions. I just wanted to add that PCB layout
> tools that generate VHDL/Verilog netlists are very useful for system level
> simulation. Obviously this is not the information the original post was
> attempting to obtain but I wanted to throw it out there for others to
> contemplate.

Matt, it is true that they are useful for system level simulation. But 
the way of the development is IMO just the opposite: _first_ you do a 
simulation, also on system level, _after this_ you design your chips and 
board. For the system level simulation you need a HDL entity, like 
�Board� that connects the HDL Units representing the chips. You can do 
this by the Testbench unit, but IMO it is a better approach to separate 
the testbench and board functions. And you are there: you have a �Board� 
HDL that contains all inter-chip connections, it would be perfect to use 
this for PCB Netlist generation.

I made already a try with this, but did not succeed.

Janos Ero

Valentin Tihomirov wrote:
> I was always considering VHDL as behaviur/logic (netlist on functional
> gates) specification language. There are no means to add more detales
> required at PCB layout abstraction layer. VHDL has no means to describe
> placement, traces and device packages. I'm I missing missing something?

I think the part you are missing is that Symon wants to replace the 
schematic portion of the PCB layout software. I does not look to me like 
he was talking about replacing the layout portion. Maybe some people put 
layout info on the schematic, but I think most do not.

-- 
My real email is akamail.com@dclark (or something like that).

"Allan Herriman" <allan.herriman.hates.spam@ctam.com.au.invalid> wrote in
message news:o0plrvk7kvd3mm2evhd0fr6nd1kdu26d3e@4ax.com...
> On Tue, 18 Nov 2003 17:49:24 -0800, "Symon" <symon_brewer@hotmail.com>
> wrote:
>
> >Hi,
> >   Does anyone out there in usenet-land know of tools to let you design
> >Printed Circuit Boards with VHDL? I'm ready to switch from schematic
entry,
> >I want portability! (And all the other good reasons I switched from
> >schematic entry for my FPGA designs) Anyone use a PCB layout tool that
> >accepts EDIF files? I see there are translator tools. Anyone ready to
share
> >their experiences, pitfalls et cetera?
>
> Features like pin swapping, gate swapping and cross probing will only
> work with a tightly integrated pcb and "source" toolset.
>
> I suspect you would lose this with an HDL front end, although they do
> seem possible in theory.
>
>
> Frankly, the thought of designing a switchmode power supply using an
> HDL scares me.  Designing a microstrip filter using an HDL seems nigh
> on impossible.
> (Hint: both these applications require careful layout, which is
> something that can be more easily expressed with a graphical entry
> tool.)
>
> Regards,
> Allan.
Hi Allen,
    Thanks for the reply! The tool I use at the moment, ORCAD, has separate
layout and schematic entry bits. So, I agree that layout, i.e. drawing the
traces, makes no sense in VHDL. However, the schematic entry is a pain in
the @rse, after all it's just wiring up components to each other. You end up
typing in lots of attributes anyway, part numbers, value, package size, pcb
footprint. Seems to me that the physical wiring of the parts is perfectly
feasible in HDL, and I can use Perl scripts to speed things along, like I do
with VHDL for my FPGA innards designs. Maybe for some things like a SMPS, a
diagram is very useful, perhaps necessary. However, for connecting a DRAM to
a FPGA, the picture adds very little if anything. Some kind of hybrid is
called for, like we already can do with logic inside FPGAs.
    Also, I would expect a HDL to be just as good at pin-swapping / gate
swapping, but, once again, I agree that layout remains inherently graphical.
As you point out the geometry of the traces is vital, and often forms part
of the circuit.

    Anyway, back to ORCAD!
            cheers, Syms.

"Duane Clark" <junkmail@junkmail.com> wrote in message
news:bpg6gk02qv@enews2.newsguy.com...
> Valentin Tihomirov wrote:
> > I was always considering VHDL as behaviur/logic (netlist on functional
> > gates) specification language. There are no means to add more detales
> > required at PCB layout abstraction layer. VHDL has no means to describe
> > placement, traces and device packages. I'm I missing missing something?
>
> I think the part you are missing is that Symon wants to replace the
> schematic portion of the PCB layout software. I does not look to me like
> he was talking about replacing the layout portion. Maybe some people put
> layout info on the schematic, but I think most do not.
>
> -- 
> My real email is akamail.com@dclark (or something like that).

Thanks Duane, you've got it exactly! I re-read my OP and can see I wasn't
too clear! (Ah, the perils of posting at the end of a busy and frustrating
day!!) I've posted again to try to clarify what I'm banging on about.
Cheers, Syms.

Symon wrote:
> 
> "Allan Herriman" <allan.herriman.hates.spam@ctam.com.au.invalid> wrote in
> message news:o0plrvk7kvd3mm2evhd0fr6nd1kdu26d3e@4ax.com...
> > On Tue, 18 Nov 2003 17:49:24 -0800, "Symon" <symon_brewer@hotmail.com>
> > wrote:
> >
> > >Hi,
> > >   Does anyone out there in usenet-land know of tools to let you design
> > >Printed Circuit Boards with VHDL? I'm ready to switch from schematic
> entry,
> > >I want portability! (And all the other good reasons I switched from
> > >schematic entry for my FPGA designs) Anyone use a PCB layout tool that
> > >accepts EDIF files? I see there are translator tools. Anyone ready to
> share
> > >their experiences, pitfalls et cetera?
> >
> > Features like pin swapping, gate swapping and cross probing will only
> > work with a tightly integrated pcb and "source" toolset.
> >
> > I suspect you would lose this with an HDL front end, although they do
> > seem possible in theory.
> >
> >
> > Frankly, the thought of designing a switchmode power supply using an
> > HDL scares me.  Designing a microstrip filter using an HDL seems nigh
> > on impossible.
> > (Hint: both these applications require careful layout, which is
> > something that can be more easily expressed with a graphical entry
> > tool.)
> >
> > Regards,
> > Allan.
> Hi Allen,
>     Thanks for the reply! The tool I use at the moment, ORCAD, has separate
> layout and schematic entry bits. So, I agree that layout, i.e. drawing the
> traces, makes no sense in VHDL. However, the schematic entry is a pain in
> the @rse, after all it's just wiring up components to each other. You end up
> typing in lots of attributes anyway, part numbers, value, package size, pcb
> footprint. Seems to me that the physical wiring of the parts is perfectly
> feasible in HDL, and I can use Perl scripts to speed things along, like I do
> with VHDL for my FPGA innards designs. Maybe for some things like a SMPS, a
> diagram is very useful, perhaps necessary. However, for connecting a DRAM to
> a FPGA, the picture adds very little if anything. Some kind of hybrid is
> called for, like we already can do with logic inside FPGAs.
>     Also, I would expect a HDL to be just as good at pin-swapping / gate
> swapping, but, once again, I agree that layout remains inherently graphical.
> As you point out the geometry of the traces is vital, and often forms part
> of the circuit.

I agree completely with you about the advantage of HDL for "schematic
capture".  Typically when you design a digital circuit you are making
lists of bus names that connect to pin names or numbers... you just do
this graphically rather than in an editor.  This is actually more work
of course, than just making the list as text.  But most people are
"comfortable" with schematics.  The advantages of using schematic with
layout really comes from the shared library rather than any inherent
feature of schematic capture.  

I remember a coworker who was telling me about a project from "hell" he
had worked on at his last job.  He inherited the work from a designer
who had left and the docs were text lists of pins to nets, NO
schematic!  This guy could not work that way and ended up doing very
poorly on that project.  

Besides, isn't a schematic a nice thing to look at?  Well, maybe not...

Would you be willing to write your design in a PCB program's netlist
format?  If you pick one that is popular (like PADS), it is portable in
that most packages will import it.  

-- 

Rick "rickman" Collins

rick.collins@XYarius.com
Ignore the reply address. To email me use the above address with the XY
removed.

Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design      URL http://www.arius.com
4 King Ave                               301-682-7772 Voice
Frederick, MD 21701-3110                 301-682-7666 FAX