2 PWM output has different freq

[spartekus]

Hi all,

I need to get 2 pwm output (not at the same time, my analog input choose which one will run). one of the pwm is around 1700 hz, another one is around 1900 hz.

any ideas why i read different frequencies at these pins, althought registers are same.
note: OC2RS also change with analog input but it is only for duty cycle as much as i know.

thanks a lot

   OC1CON  = 0b0000000000001110;
             OC1R    = 0;
             OC1RS   = 0;                              //hier müssen die daten eingeschrieben werden
             OC2CON  = 0b0000000000001110;
             OC2R    = 0;
             OC2RS   = 0;                              //hier müssen die Daten eingeschrieben werden
             T3CONbits.TCKPS0  = 1;
             T3CONbits.TCKPS   = 0;
             T3CONbits.TSIDL  = 1;
             T3CONbits.TON  = 1;
             IEC0bits.T3IE  = 0;
               PR3   = 4095;                           // PERIODENREGISTER LEGT DIE PWM FREQUENZ FEST

 

[KlausST]

Hi,

What controller do you use?
Is this the complete pwm setup?
What's the microcontroller's clock source and clock frequency?

Klaus

 

[spartekus]

Hi Klaus,

I use Pic24FJ64GA002.
yes it is all about pwm, but duty cycle of pwm change during the code, with analog input.

in case i may tell wrong, i will paste the code about freq. it is other worker's code who is not anymore.

_CONFIG1( JTAGEN_OFF & FWDTEN_ON & FWPSA_PR128 & WDTPS_PS512 )   //konfiguriert für 16MHZ
          _CONFIG2( FNOSC_FRCPLL  &  FCKSM_CSDCMD  & OSCIOFNC_ON )

      void oszillator_init()
     {
             _DOZEN = 1;
              _DOZE = 1;
            _RCDIV0 = 0;
            _RCDIV1 = 0;
            _RCDIV2 = 0;
  
     }

thanks for your answer.

correction : one of pwm is around 2.5 khz other is 1.9 khz