Re: [myhdl-list] Re: Cosimulation with the simple FSM example.

[George P. <ge...@ga...>]

>  > In one of my modules where I tried using the enum, I
>  > noticed that I got incorrect behavior (incorrect initial states, I
>  > believe) if I didn't specify the encoding style. It worked correctly
>  > when I specified 'encoding=3Done_cold'. I haven't tried other encodi=
ng
>  > styles.
>
>> This was in the synthesized hardware (Xilinx ISE w/XST). I didn't
>> co-simulate this module. Is this dependence on encoding type something
>> to
>> be expected when doing synthesis?
>
> Certainly not. It should always work. Out of the 3 possible encodings
> the default (binary) is the "least risky": as the initial
> state will be all zero's (often the default in fpga's), things may stil=
l
> work when your reset sequence doesn't work as it should. Moreover,
> once in the Verilog domain, binary encoding is basically identical
> to the simplest use of plain integers. So the problems you report
> are the opposite of what I would expect, and I haven't a clue
> on what went wrong.
>
> Cosimulation may help to clarify things in the future :-)
>
> Jan

Yeah, I think I will try that. Also, I want to try making it easier to do
co-simulation/unit testing. I'm doing my project for fun, and often I fee=
l
it hampers the fun and creativity if I have to write up (and debug!) a
unit test every time I add or change a component.

I feel my last attempt at incorporating unit testing in my design flow wa=
s
somewhat successful, however I really didn't like having to spend time
debugging the unit tests themselves! This may be easier now that I'm more
experienced with Python, myHDL, co-simulation, and hardware design (that'=
s
a lot of things to learn at once, on top of extreme programming!). Unit
testing and co-simulating *everything* still doesn't feel natural to me,
and I'm not sure if it ever will.

Speaking of promotional breaks, have you seen the new colorful photos I
took of my project? :-)

http://myhdl.jandecaluwe.com/doku.php/projects:phoenixsid_65x81

George