CAD:Just a reminder about Spectre and long simulations

Just a reminder for those who run long simulations in Cadence Spectre, especially the transient ones:

  • Set the saveclock option (in seconds) to the time interval at which you want your simulator to save its state.
  • Set the savefile option to a file name in which you want to save your state.
  • Set the recover option to a file name from which you want to load your state.

So, if you set saveclock to 60, spectre will regularly, every minute save its state to savefile. You can launch the long simulation and press stop and restart as many times as you like. Spectre will restart at the latest minut (clockwise). This is quite handy if there is a power cut or network is dropped.

Notice that the file is overwritten and if you want to save several minutes back, you need to have another script running in parallel saving that data for you. This could also be a handy strategy considering that in the worst case (which is also the most likely case according to Mr. Murphy) you might be writing to disk, just as Spectre or connection dies.

Notice also that you can alter some of the simulator settings. For example the number of nodes saved. This means you can set the simulator to log all nodes first, check them after a while, then stop. Remove some of the probes to save time/disk area, and re-run. Quite handy!

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