I'm controlling a stepper motor through a stepper driver that is connected to the raspberry pi. Before I run a script to move the motor, the pi's pins have a "floating" value causing the motor to move randomly as soon as I boot up the pi. I have noticed that "grounding" (not sure if that's the correct term) the pi, either by touching it or connecting a cat5 cable from the pi to my pc will stop this behavior, but I would like a more permanent solution. Any ideas?
It sounds like you need to add a pull up or pull down resistor to the cable causing your floating value. See
http://en.wikipedia.org/wiki/Pull-up_resistor for more information.
Since I don't have a reputation on here yet, I can't comment on Butters' answer, so I'll have to post my own answer. The GPIO of the Raspberry Pi includes pull-up and pull-down resistors that reach from 50kOhm to 65kOhm for the pull-up and 60 kOhm for the pull-down resistor. More information and code can be found in the wiki.