First, please remove you REPLY address so that a default reply goes to the
list, not just you.

> I have been having difficulties with the PWM module of the PIC18F452.
> The situation is that the device does not want to change PWM period
> (frequency) once it has been initial set.  I have tried to first turn
> off T2CON<TMR2ON> bit and also to clear the CCP1CON to disable the PWM
> first.  Still the device will not allow me to change frequency once it
> has been set for the first time.  I have been through all the data
> sheets and I have not seen anywhere in it to mention the proper way to
> change the frequency.

Then you need to re-read section 14.5 on pages 120 and 121 of DS39564A
"PIC18Fxx2 Data Sheet".  In particular see page 121, section 14.5.3
"Set-up for PWM Operations" item 1: "Set the PWM period by writing to the
PR2 register.".  Then you should re-read section 12.0 "Timer2 Module" on
pages 109 and 110 to understand how the period is generated and how the
PR2 register effects it.


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