Answer
As of engineering firmware v1.2.55.3, up to two GPIO pins may be configured as either PWN or FREQUENCY outputs. PWM outputs have adjustable frequency, and the smart BASIC function GpioWrite sets the duty cycle. FREQUENCY outputs may have a frequency from 1 to 4,000,000 Hz, but have a fixed 50% duty cycle.
Please download the latest firmware release available on the Bluetooth Download Centre to test this feature.