Hi Samoele,

The "Timer Template" was intended for a Fixed Frequency.
There's no easy way to convert it to what you want.

The SSPWM (Slow speed Software PWM) program ...
http://www.pbpgroup.com/modules/wfse...hp?articleid=6

does allow you to change either frequency or dutycycle on the fly.
But it only goes down to 16hz, and would need a 20mhz crystal to get your upper frequency.

Sorry,