Re: [usb] some question about the code of the USB function core

[Rudolf Usselmann <rudi@asics.ws>]

On Saturday 30 March 2002 02:40 pm, you wrote:
> Hi,Rudi and all:
>
>    I have some questions about the USB function core.
> The first is that how can I re-simulate the core as I cannot
> find anything in the dictory of bench. I want to learn how
> to get a full simulation about the core.

How about writing a test bench ???

I've been asking for someone to help to write a test bench, but 
nobody wants to do it ...

> The second is that I have seen some code in the module of the core
> like that following :
>
> always @(posedge clk)
> 	clr_sof_time <= #1 frame_no_we;
>                     ~~~~~ that means to assign the value after one unit
> time
>
> In my opinion, to add one unit time delay in the code is to minimize
> the difference between the RTL simulation and the synthesized gate-level
> simulation. But that code may not be supported by the synthesis tools.
> Is that true ? How can I change the core into synthesisable ?

No this does not bring rtl closer to gate level simulations. Timing
will always differ depending on your technology. The "#1" is really
absolutely meaningless. The only reason I like to add them is
because it makes debugging of rtl so much easier.

This core is absolutely 100% synthesizable. Every synthesis tool
will ignore the "#1".

rudi

> Thanks for your answer.
>
> Best regards.
>
>
> Jiang daosan
> jiangdaosan@21cn.com


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