I'm using a MCF5213 with an external master clock. I'm also using one of the 5213 PWM outputs to drive a MOSFET to control the speed of a fan. If I stop the master clock, I notice that the PWM will continue to run. I'd like the PWM to stop when the master clocks stops. Why does the PWM continue to run, and how can I get it to stop when the master clock is halted?