PWM.c

#include <xc.h>
#include <stdio.h>
#include "configBits.h"
#include "lcd.h"
#include "macros.h"
#include "constants.h"

long freq; 
unsigned int i = 0; 


int PWM_Max_Duty()
// Returns the register values to be set for 100% duty cycle, this is dependent
// on the PWM frequency and oscillator frequency
// https://electrosome.com/pwm-pic-microcontroller-mplab-xc8/
{
  return(_XTAL_FREQ/(freq*TMR2PRESCALE));
}
  
void set_PWM_freq(long fre)
// Sets PR2 register to match the frequency desired
// See datasheet pg 149, equation 16-1
// https://electrosome.com/pwm-pic-microcontroller-mplab-xc8/
{
  PR2 = (_XTAL_FREQ/(fre*4*TMR2PRESCALE)) - 1;
  freq = fre;
}

void set_PWM1_duty(unsigned int duty)
// Sets the duty cycle of PWM1, from 1024 to 0
// See datasheet pg 150, equation 16-1
// https://electrosome.com/pwm-pic-microcontroller-mplab-xc8/
{
  if(duty<1024)
  {
    duty = ((float)duty/1023)*PWM_Max_Duty();
    CCP1X = duty & 2; // Set the 2 lest significant bit in CCP1CON register
    CCP1Y = duty & 1;
    CCPR1L = duty>>2; // Set rest of the duty cycle bits in CCPR1L
  }
    
}

void set_PWM2_duty(unsigned int duty)
// Sets the duty cycle of PWM2, from 1024 to 0
// See datasheet pg 150, equation 16-1
// https://electrosome.com/pwm-pic-microcontroller-mplab-xc8/
{
  if(duty<1024)
  {
    duty = ((float)duty/1023)*PWM_Max_Duty();
    CCP2X = duty & 2; // Set the 2 lest significant bit in CCP2CON register
    CCP2Y = duty & 1;
    CCPR2L = duty>>2; // Set rest of the duty cycle bits in CCPR2L
  }
}

PWM1_Start()
// START PWM1 OUTPUT, PWM1 have enhanced features, see datasheet
{
  //Configure CCP1CON, single output mode, all active high
  P1M1 = 0;
  P1M0 = 0;
  CCP1M3 = 1;
  CCP1M2 = 1;
  CCP1M1 = 0;
  CCP1M0 = 0;
  

  T2CON = 00000011;


  // Enable timer 2
  TMR2ON = 1;
  // Enable PWM output pins
  TRISCbits.TRISC2 = 0;
}

PWM2_Start()
// START PWM2 OUTPUT
{
  //Configure CCP2CON, enter PWM mode
  CCP2M3 = 1;
  CCP2M2 = 1;
  
  //Configure prescale values for Timer2, according to TMR2PRESCALAR
  #if TMR2PRESCALAR == 1
    T2CKPS0 = 0;
    T2CKPS1 = 0;
  #elif TMR2PRESCALAR == 4
    T2CKPS0 = 1;
    T2CKPS1 = 0;
  #elif TMR2PRESCALAR == 16
    T2CKPS0 = 1;
    T2CKPS1 = 1;
  #endif

  // Enable timer 2
  TMR2ON = 1;
  
  // Enable PWM output pins
  TRISCbits.TRISC1 = 0;
}

PWM1_Stop()
// Stop PWM1 output
{
  CCP1M3 = 0;
  CCP1M2 = 0;
  CCP1M1 = 0;
  CCP1M0 = 0;
}

PWM2_Stop()
{
  CCP2M3 = 0;
  CCP2M2 = 0;
  CCP2M1 = 0;
  CCP2M0 = 0;
}

/*void main(void) {

     
    // Configure PWM frequency, 50khz
    // Scale for pwm is not linear, see datasheet pg150

    //TRISB = 0x00;
    while(1){
        // LATCbits.LATC3 = 1 - LATCbits.LATC3 ; // This line of close flashes RC3 every iteration of the loop
        set_PWM1_duty(i);
        LATB = i>>2;
        if(i <= 1020)
          i= i+10;
        else
            i = 0;
        delay_10ms(10);
    }
  }
*/