The gyro (Yaw Rate Sensor) connects to the controller as a digital input and the PBASIC code interprets the input and determines what to do. Check out the Technokats Auto-Balance Code from last year if you're wondering how the PBASIC works for it. The code is in the White Papers or at the following link.
http://www.chiefdelphi.com/forums/pa...per&paperid=10