AT90PWM Prescaler

Hi

>Warum? Ich müsste doch mit CLKPR-Register, die PWM-Frequenz ändern
>können!?

Kannst du auch. Aber zum Einstellen des Prescalers ist ein bestimmter 
Timing notwendig. Also noch mal Datenblatt lesen.

MfG Spess

Hallo!

Vielen Dank für euere Antworten.
Leider funktioniert es noch nicht, kann mir jemand sagen, was ich in 
meinem Code falsch mache. Wo liegt der Fehler beim beschreiben des 
Prescaleregisters?

#include <avr/io.h>
#include <avr/interrupt.h>

//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
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// Ramp_Mode_Selection
  int ramp_mode = 0;    // Mode: 
4=Four_Ramp/2=Two_Ramp/1=One_Ramp/0=Center_Aligned

// Define_Times

  float DUTY_CYCLE;
  double PSC_CYCLE;
  double   DEAD_TIME_0;
  double   DEAD_TIME_1;
  double  ON_TIME_0;
  double  ON_TIME_1;
//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
xxxxxxxxxxxxxxxx



void init_pwm_values(void)
{


};

// PWM_Overlapping_Selection
void init_lapping(void)
{
  int pwm_overlapping = 0;   // Mode: 0=non_overlapping/1=overlapping

    if(pwm_overlapping == 1)
    {
    DEAD_TIME_0 = 50;
    ON_TIME_0 = 100;
    DEAD_TIME_1 = 75;
    ON_TIME_1 = 125;
    }
    else
    {
    DEAD_TIME_0 = 50;
    ON_TIME_0 = 75;
    DEAD_TIME_1 = 100;
    ON_TIME_1 = 125;
    }

}

// Power_Stage_Controll_2_Initalisation
void init_psc2(void)
{
  //PCNF2 = (0<<PCLKSEL2); // Slow_Clock_Input //CLK_I/O

  CLKPR = (1<<CLKPCE)|(0<<CLKPS3)|(0<<CLKPS2)|(0<<CLKPS1)|(0<<CLKPS0);

  CLKPR = (0<<CLKPCE)|(0<<CLKPS3)|(1<<CLKPS2)|(1<<CLKPS1)|(1<<CLKPS0);

  PSOC2 = (1<<POEN2A)|(1<<POEN2B);

  OCR2SA = DEAD_TIME_0;

  OCR2RA = ON_TIME_0;

  OCR2SB = DEAD_TIME_1;

  OCR2RB = ON_TIME_1;
}

// Ramp_Mode_Initialisation
void init_ramp_mode(void)
{
    switch (ramp_mode)
    {
      case 4:
      PCNF2 = (1<<PMODE21)|(1<<PCLKSEL2)|(1<<POP2); // Four_Ramp_Mode
      break;

      case 2:
      PCNF2 = (1<<PMODE20)|(1<<POP2); // Two_Ramp_Mode
      break;

      case 1:
      PCNF2 = (0<<PMODE21)|(0<<PMODE20)|(1<<POP2); // One_Ramp_Mode
      break;

      case 0:
      PCNF2 = (1<<PMODE21)|(1<<PMODE20)|(1<<POP2)|(0<<PCLKSEL2); // 
Center_Aligned_Mode // Slow_Clock_Input (PCLKSEL2 = 0)
      break;
    }
}

// Power_Stage_Controll_Input_Initialisation // page:167
void init_psc_input(void)
{
  PFRC2A = 0;
  PFRC2B = 0;
}

// PWM_Output_Selection
void init_pwm_out(void)
{
  //PCTL2 = (0<<PPRE21)|(0<<PPRE20); // No_Divider_On_PSC_Input_Clock

  PCTL2 = (1<<PRUN2); // PWM_Output_enable
}

int main(void)
{

  //init_pwm_values();
  init_lapping(); // Exclude_from_build_for_defining_divergent_times
  init_psc2();
  init_ramp_mode();
  init_psc_input();
  init_pwm_out();

    while(1)
    {
    }


}

Wäre nett, wenn mir jemand weiterhelfen könnte!

Danke!

Gruß