Advertisement
Guest User

PWM Test

a guest
Mar 21st, 2015
45
Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. #define F_CPU 1000000 // The chip runs at 1 MHz as default (even if you are using a 8MHz crystal), this line is necessary for delay function
  2.  
  3. #include <avr/io.h>
  4. #include <avr/interrupt.h>
  5. #include <util/delay.h>
  6.  
  7. //Timer 0 initialisation
  8. void init_timer0 ()
  9. {
  10.     //Set registry bits for timer
  11.     TCCR0B      = 0b00000001;   //Set up timer 0 with no prescaler
  12.     TCNT0       = 0b00000000;   //Initialise counter
  13. }
  14.  
  15. int main()
  16. {
  17.     //Variables
  18.     char ch_R_on_dur    = 1;    //Number of counts channel R should remain on for
  19.     char ch_R_off_dur   = 254;  //Number of counts channel R should remain off for
  20.     char ch_R_count     = 0;    //Counter tracking amount of time channel R has remained on/off
  21.  
  22.     char ch_G_on_dur    = 0;    //Number of counts channel G should remain on for
  23.     char ch_G_off_dur   = 0;    //Number of counts channel G should remain off for
  24.     char ch_G_count     = 0;    //Counter tracking amount of time channel G has remained on/off
  25.  
  26.     char ch_B_on_dur    = 0;    //Number of counts channel B should remain on for
  27.     char ch_B_off_dur   = 0;    //Number of counts channel B should remain off for
  28.     char ch_B_count     = 0;    //Counter tracking amount of time channel B has remained on/off
  29.  
  30.     char ch_W_on_dur    = 0;    //Number of counts channel W should remain on for
  31.     char ch_W_off_dur   = 0;    //Number of counts channel W should remain off for
  32.     char ch_W_count     = 0;    //Counter tracking amount of time channel W has remained on/off
  33.    
  34.     //Initialise Timer
  35.     init_timer0();
  36.    
  37.     //Initialise LED output
  38.     DDRC    = 0b10000000;   //Sets the direction of the PC7 to output
  39.     PORTC   |= (1<<PC7);    //Sets PC7 high
  40.  
  41.     //Keep LED on at 100% for 2 seconds to show difference in output when PWM starts
  42.     _delay_ms(2000);
  43.  
  44.     while(1)
  45.     {
  46.         //Update counters
  47.         //If timer has ticked, update counters
  48.         if (TCNT0 >= 1)
  49.         {
  50.             //Increment counters
  51.             ch_R_count++;
  52.             //Increment Green counter
  53.             //Increment Blue counter
  54.             //Increment White counter
  55.  
  56.             //Reset timer
  57.             TCNT0 = 0;
  58.         }
  59.        
  60.         //Cycle red led on and off at high speed
  61.         //If channel R has been off for max duration
  62.         if (PORTC == 0b00000000 && ch_R_count >= ch_R_off_dur)
  63.         {
  64.             //Turn channel R on
  65.             PORTC |= (1<<PC7);
  66.            
  67.             //Reset channel R overflow counter
  68.             ch_R_count = 0;
  69.         } else {
  70.         //If channel R has been on for max duration
  71.         if (PORTC == 0b10000000 && ch_R_count >= ch_R_on_dur)
  72.         {
  73.             //Turn channel R off
  74.             PORTC &= ~(1<<PC7);
  75.    
  76.             //Reset channel R overflow counter
  77.             ch_R_count = 0;
  78.         }}
  79.  
  80.         //Cycle Green LED
  81.        
  82.         //Cycle Blue LED
  83.        
  84.         //Cycle White LED
  85.     }
  86.  
  87.     //End program
  88.     return 0;
  89. }
Advertisement
RAW Paste Data Copied
Advertisement