RE: VHDL-AMS PLI and a Question about the Simulation Cycle

Sameer,

Your statement about the analog solver executing at every digital event is not correct.
The execution of the analog solver is related to cycles, not events. There are cycles with
more than one event, and there are cycles with no event at all.

Regarding the second part of your question, I direct you again to section 12.6.6 of the
LRM, which defines what the execution of the analog solver involves. You should be able to
draw the right conclusion from this section or point to an ambiguity in the definition
that prevents you from reaching a conclusion.

Ernst Christen

On Thu, 4 Jan 2007 14:51:29 -0500, Sameer Kher wrote:
> Thanks Ernst,
>
> So I am correct in my interpretation of the simulation cycle that the
> analog solver must be executed at every digital event (perhaps excluding
> some delta cycles) irrespective of whether the digital event affects the
> analog system or not?
>
> Thanks John and Martin for the information about the VHPI.
>
> Sameer
>
> -----Original Message-----
> From: Ernst Christen [mailto:Ernst.Christen@synopsys.COM]
> Sent: Thursday, January 04, 2007 2:02 PM
> To: Sameer Kher; vhdl-ams@vhdl.org
> Subject: Re: VHDL-AMS PLI and a Question about the Simulation Cycle
>
> Sameer,
>
> Step a) defines that "The analog solver is executed." Therefore, the
> analog solver executes at the beginning of each simulation cycle. Clause
> 12.6.6 then defines the actions that the analog solver takes when it
> executes. These actions depend on the result of step
> g) and other steps, more specifically whether the break flag is set and,
> to some extent, whether this is a delta cycle or not.
>
> Ernst Christen
>
> On Thu, 4 Jan 2007 10:23:07 -0500, Sameer Kher wrote:
>> Also, I was seeking a clarification on the simulation cycle as
>> described in the LRM. My question is related to step (g) where the
>> next simulation time is determined. The text says that the next
>> simulation cycle "...is determined by setting it to the earliest of :
>> - The value of type universal_time corresponding to TIME'HIGH
>> - The next time at which a driver becomes active, or
>> - The next time at which a process resumes..."
>> Does this imply that the analog solver must execute at every digital
>> event?
>>
>> Thanks,
>> Sameer Kher
>> R&D Engineer
>> Ansoft Corp.


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