Should I Use glitch_hp or glitch_lp?

All ChipWhisperer scopes (except for the CW-Nano) offer a choice of two different MOSFETs for executing crowbar voltage glitches. Our Jupyter course notebooks mention their existence and suggests which to use for different targets but doesn’t explain the choices.

When doing voltage glitching, you can use one or both of glitch_hp and glitch_lp, so you have a total of three options.

In general, glitch_lp provides a faster response (so sharper and narrower glitches are possible) while glitch_hp can be better for targets that require more power. This is discussed in Colin’s crowbar paper.

As with glitching in general, there is no one-size-fits-all! It really depends on your target. Consider the MOSFET choice as just one more variable, just like all the scope.glitch parameters.