Analog Design Resonance: When a Plan Comes Together

Yes, indeed, we all love it when a plan comes together. A plan for running all the simulations you need, using different combinations of tests, corners, variables, and run modes. A plan that you can execute with a single button before you go home in the evening. A plan that will stop if, for some reason, your design isn't performing to spec so that you aren't wasting resources running simulations on a bad design. The Run Plan Assistant in Virtuoso ADE Assembler is designed to do all this and more.

What Is a Run Plan?

• A Run Plan is a sequence of runs created from different variants of the active Assembler setup.
• The execution of each run can depend on pass/fail conditions occurring in other runs.
• Scripts can be inserted before and after each run to perform user-specified actions and pass results from one run to another.
• Run Plans can be executed either from the UI in the Run Plan Assistant, or written out as a script to run in batch mode from the command line.

Getting Started

Open the Run Plan Assistant using the Create->Run Plan banner menu in ADE Assembler. The easiest way to get started is to use the first icon "Create New Run from Active Setup". This adds an entry in the assistant containing what you have currently defined in your Assembler setup. Now you can modify that information in the Run Plan Assistant to do things such as enabling/disabling tests and corners, changing the run mode (for example, from "Single Run, Sweeps, and Corners" to "Monte Carlo Sampling"), and modifying variable and parameter values. Changes you make here do not affect the active setup. Be aware, however, that changes you make in Assembler to the test setup itself (analysis options, simulator settings, outputs, specifications) will be used wherever that test is enabled in the Run Plan. The Run Plan is not a copy of the active setup. Think of it as a set of pointers with the ability to override certain elements.

You can repeatedly use the "Create New Run from Active Setup" button to add runs into the Run Plan, modifying the settings for each one. If you need to run some tests over corners and other tests with Monte Carlo, it's easy now.

Conditions and Dependencies

One of the most powerful capabilities of Run Plans is the ability to create conditions on each run that must be met in order for the run to start. Do this by clicking the right mouse button on a run and selecting "Edit Run Conditions". Here you can set up conditions for a run based on successful simulation completion, specifications passing, and/or yield thresholds.

On this Run Conditions form, you can also provide Skill scripts which can be executed before or after each run. In this way, you can, for example, grab a measured value from one run and use it to set the value of a variable in a subsequent run. The new mae* API functions (more on that in another post) make it easy to access setup and results from the maestro database.

Ready, Set, Go!

Run Plans can be executed using the "Execute Plan" button in the Run Plan Assistant, or you can use the "Save Script" icon to save a script, which you can use to execute the Run Plan from the command line. If you have a distributed job policy (and who doesn't?), all the runs within the Run Plan will fire off in parallel, unless, of course, you have created dependencies and conditions, in which case we will sort those out and stage the simulations accordingly.

While the simulations are running, the display will switch to the Status tab, which has been enhanced to provide a nice summary of the Run Plan progress, including hyperlinks to open the results from the individual runs.

More Information

• Run Plan Rapid Adoption Kit
• Creating Run Plans in Virtuoso ADE Assembler Video