Tag: Skill

Shortcut to plot relative to reference signal

Ocean/skill script follows. Select a net. Press ctrl-g. Now that net is your “reference”. Select a different net (or the same net if you are fond of trivial signals). Press ctrl-r that second net is plotted relative to the reference. This is useful for debugging multiple supply domains, supply/ground bounce, and differential circuits. relVt.il:

Creating a Nyquist plot with Cadence

Cadence has a stability analysis that returns loop gain (return ratio). Typically, this is done using a log sweep of frequency. The reason is that doing a uniform linear sweep results in too large frequency steps for low frequencies and/or too large of a step for higher frequencies. Unfortunately, when you do a logarithmic sweep, […]

For loops in Cadence

If one is doing an analysis over a range of variables, one should use the paramAnalysis ocean function. That said, I’m constantly having to look up how to do a for loop in Skill. So, I’m placing a couple examples where I know I can get to them.

Getting subversion and Cadence to play nice

I wrote a set of scripts to make Cadence IC tools & Subversion work together. Note: this is not actual Cadence/Subversion integration (which is much more powerful and highly recommended). There were a few problems that I had to solve: Pesky .svn directories The main problem is that Subversion puts .svn housekeeping directories everywhere. When […]