Re: suggestion

Maybe you want a new type (say) realtime e.g.:

  realtime td = 1.2345ns;

  # td;          // as near a 1.2345ns delay as poss.

Kev.

Scott Cranston wrote:
> I don't have any concrete ideas on the syntax, although it does not seem
> that difficult to work out, but I don't think you need a time unit
> specifier, like 1ns - you would only need to specify the scale factor
> (p, n, u) which is already there in the language. The notion of time
> (and hence the units, seconds) is already present by virtue of the fact
> that you are specifying a delay.
>
> As far as using a variable with a scale factor, you could easily write
>
> #(td * 1n)
>
> or you could even build a unit specifier into the proposed syntax
> itself, something like:
>
> #{1n}(td)
>
> In general it is better to be as clear and straightforward as possible,
> IMO.
>
>        -- Scott
>
>
>
>
>
>   
>>>>> -----Original Message-----
>>>>> From: Ken Kundert [mailto:ken@designers-guide.com] 
>>>>> Sent: Wednesday, August 29, 2007 1:56 PM
>>>>> To: Scott Cranston
>>>>> Cc: verilog-AMS LRM Committee
>>>>> Subject: Re: suggestion
>>>>>
>>>>> Scott,
>>>>>    Would it be keying off the presence of ns? How would 
>>>>> this work if I wanted to use a variable? Would I use
>>>>>    #(td ns);
>>>>> Wouldn't that imply that s, ms, us, ns, ps, fs, etc. would 
>>>>> all have to be keywords?
>>>>>
>>>>> -Ken
>>>>>
>>>>> Scott Cranston wrote:
>>>>>           
>>>>>> What you really want is a way to specify time absolutely, correct?
>>>>>>
>>>>>> Something like #(1ns) where the 1ns is not scaled.
>>>>>>
>>>>>> That seems like a clearer way to do what you want.
>>>>>>
>>>>>>    -- Scott
>>>>>>
>>>>>>
>>>>>>             
>>>>>>>>>> -----Original Message-----
>>>>>>>>>> From: owner-verilog-ams@eda.org
>>>>>>>>>> [mailto:owner-verilog-ams@eda.org] On Behalf Of Ken Kundert
>>>>>>>>>> Sent: Tuesday, August 28, 2007 11:44 PM
>>>>>>>>>> To: verilog-AMS LRM Committee
>>>>>>>>>> Subject: suggestion
>>>>>>>>>>
>>>>>>>>>> All,
>>>>>>>>>>    It would be very handy to have access to the 
>>>>>>>>>>                     
>>>>> `timescale value 
>>>>>           
>>>>>>>>>> from within a model so that we can write delays in 
>>>>>>>>>>                     
>>>>> terms of time 
>>>>>           
>>>>>>>>>> rather than ticks.
>>>>>>>>>>
>>>>>>>>>> Just to throw something out, say $tick returns the 
>>>>>>>>>>                     
>>>>> length of a 
>>>>>           
>>>>>>>>>> tick in seconds. Then one can use it in the digital 
>>>>>>>>>>                     
>>>>> portion of the 
>>>>>           
>>>>>>>>>> model as in the following example (a d flip-flop that 
>>>>>>>>>>                     
>>>>> implements 
>>>>>           
>>>>>>>>>> 1n of delay regardless of how `timescale was specified) ...
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> parameter real td = 1ns;
>>>>>>>>>> ...
>>>>>>>>>>
>>>>>>>>>> always @(posedge clk) begin
>>>>>>>>>>    q = #(td/$tick) d;
>>>>>>>>>> end
>>>>>>>>>>
>>>>>>>>>> -Ken
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> This message has been scanned for viruses and 
>>>>>>>>>>                     
>>>>> dangerous content by 
>>>>>           
>>>>>>>>>> MailScanner, and is believed to be clean.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>                     
>
>   


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