Can the frequency be changed in the software as well as the dutycycle %
In the instructions you mentioned that the frequency is fixed at +/- 47kHz ??
But is it possible to change that by software ??
Actually it sounds like you have the K8055N.
Since it is stated that the frequency is fixed it can not be changed.
You can change the dutycycle
Indeed I have the K8055N.
Okay that let me to make a PWM-system that makes this possible.
eg. a LM 555 with adjustible dutycycle (by the Analog output 2) and frequency changed by the dutycycle of the PWM 1 from the card.