Power Pwm Module on DSPIC30F1010

[BenWhitby]

Dear Sirs

I am currently trying to use the Power PWM Module on the DSPIC30F1010.To clock the device i am using a 15MHz external crystal in the HS w/PLL 32x mode. This should give me a frequency of 120Mhz (30MIPS), yes? I am using the standard edge aligned PWM mode and a attempting to generate a square at a fixed frequency of 50KHz(Period 20us). I have lots of experience using the standard PWM Output Capture Modules on 16 series pics but this is the first time i have attempted using the power pwm module on the DSPIC devices.

Could anyone tell me what formula i need to use to calculate the PTPER value that will enable me to obtain a switching frequency of 50KHz. Also how do i calculate the maximum duty cycle and the duty cycle resolution on the power pwm module? I know that on standard PICS the Max duty cycle = Fosc/(Fpwm*preScaler). Any help would be much appreciated.

Can someone also confirm that in order to clock the device in the manner stated above i should be using the PR_PLL fuse.

Thanks

Thanks
Ben