Date: Fri Nov 30 2007 - 04:36:25 PST
Hi Geoffrey, Regarding the analog initial block - I specifically used the wording "at most once" so that if none of the "input" values for an analog initial block changes, it does not need to be updated. This was also discussed this way in the conference call last night. I guess that for many compact models temperature scaling has a very natural place in an analog initial block. Cheers, Marq To cc "Geoffrey.Coram" verilog-ams <geoffrey.coram@anal <verilog-ams@server.eda-stds.org> og.com> Subject Re: minutes Verilog-AMS committee Sent by: meeting November 29, 2007 owner-verilog-ams@se Classification rver.eda.org 30-11-2007 12:50 Sorry I keep missing the calls. Marq Kole wrote: > * Still some discussion was brought up on whether the analog initial > blockwas necessary - its benefit over a regular initial_step event > is that it is guaranteed to be executed at most one time during > each analysis task. The proposal I saw from Martin says you will get one execution per step of a dc sweep. This is because some people (eg, compact model writers) want to put temperature-adjustments in a special block so they "know" it gets done once for transient, but if you're sweeping temperature, it needs to be done more than once. On the other hand, if you're sweeping a voltage source external to the module, then the analog initial block does *not* need to be re-executed. Are we *requiring* the simulator to re-exec the block? Although Martin's e-mail said the a.i.b. was for "initialization such as reading data from a file," that's not in the LRM, and we can't prevent compact-modelers from using the block for other purposes. > * Another item was Dave's comment on using OOMRs in an analog > initial block. As the analog initial block is executed when the > elaboration is finished, a variable OOMR should be allowed - there > were questions on whether an analog variable OOMR was possible > because of lacking derivative information. Sri will make a > subsection to section 6.6 (Hierarchical names) to describe exactly > what is allowed with hierarchical references and hierarchical names. As to the variable OOMR: if it's in the analog initial block, then the OOMR should not be allowed to reference a variable that depends on a voltage, just as statements in the analog initial block can't have access functions in them, so the derivative information should always be zero. Dave's concerns about race conditions should be expressed in the LRM as a caution. -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.
