Hi Geoffrey, I think this seems a bit confusing. 'Above generating an event would mean that there is some process somewhere that would be sensitive to this event and use it (at least that is a traditional concept of events and sensitivity). Here it is being used to do what? Disable a $strobe if it had occurred once before and the definition of occurrence is related to the execution in different DC operating point analysis performed in a DC Sweep? Interesting. Has the simulation cycle for Verilog-AMS been modified to define when this event is processed? With the merge to SystemVerilog it will be interesting to see how you define the DC Sweep in the context of the simulation cycle. Regards David David W. Smith Synopsys Scientist Synopsys, Inc. Synopsys Technology Park 2025 NW Cornelius Pass Road Hillsboro, OR 97124 Voice: 503.547.6467 Main: 503.547.6000 Cell: 503.560.5389 FAX: 503.547.6906 Email: david.smith@synopsys.com http://www.synopsys.com Saber Accelerates Robust Design Predictable. Repeatable. Reliable. Proven. -----Original Message----- From: owner-verilog-ams@eda.org [mailto:owner-verilog-ams@eda.org] On Behalf Of Geoffrey.Coram Sent: Thursday, November 19, 2009 9:15 AM To: David Smith Cc: verilog-ams@eda.org Subject: Re: @above in analyses other than tran and dc sweep David Smith wrote: > > Having one DC solution have a dependency on a different DC solution within a DC sweep seems like a bad idea to me and not consistent with the traditional definition of a DC sweep. As mentioned before, there are circuits that have multiple dc solutions, in particular hysteresis, so you can't say "the" dc solution. People do design these circuits intentionally! > If it means that an event is generated going from one DC solution in a DC sweep to another then a rational would be helpful to understand the need. There is an example in the LRM of a sample and hold that uses above to get the correct time=0 solution when the smpl pin is initially high, but this doesn't need an event during a dc sweep. Not in the LRM, but in a discussion document from the subcommittee when we added above, was a discussion about not giving repetitive warning messages. For example @above( BV - V(a,c)) $strobe("Diode is breaking down."); Clearly, if one does if( BV - V(a,c) < 0) $strobe("Diode is breaking down."); then one could get this message for dozens or hundreds of points in a dc sweep, which could be quite messy, and doesn't give any new information. -Geoffrey -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.Received on Thu Nov 19 09:34:24 2009
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