Re: [f-cpu] Free synthesis tool for Verilog and other links

[Just an Illusion <illusion_to_net@yahoo.fr>]

Hi,

Ben Franchuk wrote:
<cut>

>> i don't understand the last part of the question.
>> However, VHDL allows you to replace one version of a module ("entity" in
>> VHDL jargon) with another version ("architecture" in VHDL, which can be
>> written differently or even include a technology-specific description
>> (hierarchical or flat netlist for example).
>
>
>   I can do that with schematics too. I will re-state the question.
> Is the net-list in a form that can still be read by people if you want
> to tweek the code by hand?
>
The problem with schematics is that they are in proprietary format, 
which are incompatible between tools.
More, synthesizer don't like them (I don't no why but when I try to give 
them circuit like postscript, jpeg, png files... They crush :-D).

It seems than some peoples misunderstood what we have in a hdl code 
(verilog or vhdl).

With the same language, we can describe 3 main level of abstraction of 
the same design (or function) :

- The behavioral level, where you describe the dataflow treatment 
without any preoccupation of register transmission, synchronism 
implementation...
- The structural level (named *rtl*, for Register Transfert Level), 
where you describe one of the implementation possibility of the previous 
behavioral model. At this level, you need define the registers, the 
synchronism clocks...
- The gate level (or netlist) where you made a implementation of the 
previous levels, and describe like primary blocks interconnexion.


About remarks of Whygee about couple entity/architecture, when you want 
simulate, synthesize, check... the design you need give a couple of 
"elements" which describe in on hand the external interface (the 
"entity") and in the other hand the behavior code (the "architecture").
The most important thing about optimization is than you can easily 
change your behavioral code, without modify all the system, if your 
custom code have the same functionnality (and more respect the same 
communication protocol). The internal block treatment isn't important in 
that case.

Cheers,
Just an Illusion

-- 
______________________________
"The matrix is my world, I am a shadow.
Shadow in world, shadow in life. Don't try to keep me,
I am a Corpo's Killer.
Don't follow me or die..."
		The KingWalker - 1996



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