(Seeing problem on the Mega 2560 using Arduino 1.0.3 IDE)
Reproduction:
1. Call SoftPWMBegin() in setup
2. Call analogWrite(9, x) with varying values for x
3. Only 0% or 100% duty cycles are output on the pin. There is no fading if you
attach an LED.
4. All other hardware PWM pins I've tried worked fine