Re: [myhdl-list] Unable to get a counter working

[Jan D. <ja...@ja...>]

Andrew Lentvorski wrote:
> Could someone please explain to me what I'm doing wrong?  I'm trying to
> implement what would be a basic PC counter in a microprocessor.  The
> stage has two def's: pc_logic which should basically just be a
> combinatorial adder and pc_flops which captures the state of the
> combinatorial logic on an edge.
> 
> Why doesn't this work?  Worse, why does the one commented line throw a
> UboundLocalError error?

See Gunter's post for the answer in a MyHDL context.

For clarity, I would like to add that the issue is conceptually not related
to something MyHDL-specific, but to the semantics of assignment and
local namespaces in Python. These work differently than in many other
languages and it is important to understand this clearly. See also:

   http://www.network-theory.co.uk/docs/pytut/PythonScopesandNameSpaces.html

Regards,

Jan

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