/* PPWM Generator -  BT 4_20_15                                                             */
/* This program is a simple PWM generator                                                   */
/* Basically all it is doing is shifting 1s and 0s out of Port B                            */
/* The realtime delay creates the 80/20 duty cycles waveform                                */
/*                                                                                          */

#include <avr/io.h>                                          //standard Atmel include

static void PWM_Generator()
 { 
 uint8_t i;

 while(1){
   for (i = 0; i < 250; i++) {
     PINB |= (1 << PINB3) | (1 << PINB2) | (1 << PINB1) | (1 << PINB0);    //shifting bytes to create a toggle at Pin B "1"
     delay_us(3000 * 2 / 10);                                                                  //20% of 3mSec for the "1" part of the pulse

     PINB |= (1 << PINB3) | (1 << PINB2) | (1 << PINB1) | (1 << PINB0);   //shifting bytes to create a toggle at Pin B "0"
     delay_us(3000 * 8 / 10);                                                                 //80% of 3mSec for the "0" part of the pulse
     }

   for (i = 0; i < 250; i++) {
     PINB |= (1 << PINB3) | (1 << PINB2) | (1 << PINB1) | (1 << PINB0); //shifting bytes to create a toggle at Pin B "1"
     delay_us(3000 * 8 / 10);                                                               //80% of 3mSec for the "1" part of the pulse 

     PINB |= (1 << PINB3) | (1 << PINB2) | (1 << PINB1) | (1 << PINB0); //shifting bytes to create a toggle at Pin B "0"
     delay_us(3000 * 2 / 10);                                                              //20% of 3mSec for the "0" part of the pulse
     }
 }