SparkFun Forums

[bigglez]

I'm looking for what you mean by clamping diode and can't seem to find anything online. Do you mean a diode between the micro and transistor?

No. The clamping diode, which may also be called a
back-EMF diode, catch diode, or even snubber diode,
is in parallel with the load (motor). Alternatively it
may connect in parallel with the load switch (FET).
Its role is to clamp unwanted energy from the load
(your motor) that may feedback into and upset the
other circuitry.

One should not rely on the internal diode of a PMOSFet,
which is an artifact of the transistor's construction. Often
the diode is inferior to the FET, and abuse may lead to
failure of the transistor.

A schematic of your intended circuit would go a long
way to helping us help you, by cutting out the guess
work on both sides. Really.

[signal7]

It's also called a freewheeling, supressor, or flyback diode. It's connected across the motor windings to prevent an inductive spike when the field in the motor windings collapses.

http://en.wikipedia.org/wiki/Flyback_diode

I've spent a lot of time reading wikipedia electronics posts lately. I'm amazed at the wealth of information on the subject posted there. It almost invalidates my text books from when I was in college.