sine_wave.c

sine wave genration using atmega8

/*****************************************************
Project : 
Version : 
Date    : 12/1/2008
Author  : HAMSA LATA                      
Company : RUPANAGUDI                      
Comments: 

Chip type           : ATmega8
Program type        : Application
Clock frequency     : 8.000000 MHz
Memory model        : Small
External SRAM size  : 0
Data Stack size     : 256
*****************************************************/
#include<mega8.h>
flash unsigned char pwmtab[59]={128,141,154,167,180,192,203,214,223,231,239,245,249,
                                252,254,254,253,251,247,242,235,227,218,209,198,186,
                                174,161,148,134,121,107,94,81,69,57,46,37,28,20,
                                13,8,4,2,1,1,3,6,10,16,24,32,41,52,63,75,88,101,114};  

unsigned char index = 0;  

// Timer 2 output compare interrupt service routine
interrupt [TIM2_COMP] void timer2_comp_isr(void)
{OCR2=pwmtab[index];
 index++;
 if(index>58) index=0;
}

//------------------------------------------------------------------------------
#define no_push         0
#define maybe_push      1
#define push            2
//------------------------------
#define t1              2  
//------------------------------  
#define set_alarm       1
//-----------------------------  
#define set_month_date  1  
#define set_hour_min    2  
#define set_day         3  
#define set_normal      4     
//----------------------------
bit push_flag = 1;   
unsigned char time1=0,set_state;
void debounce(void)
{ static char push_state,push_count;
  time1 = t1;                              
  if(~PIND.2 == 0)
     {set_state = set_alarm;
      }
  //---------------------------------------
  switch(push_state)
       {case no_push:if(PIND.3 == 0)  
                      {push_state = maybe_push;  
                       push_count = 0;
                       }else{push_state = no_push;
                             }
                     break;
        case maybe_push:if(PIND.3 == 0)
                          {if(++push_count == 5)
                             {push_state = push;
                              push_flag = 1;
                              }
                           }else{push_state = no_push;
                                 }
                         break;
        case push:if(PIND.3 == 0)  
                    push_state = push;
                   else
                    push_state = no_push;
                   break;
         }

}

 


//_______________________________________________________________________________
void main (void)
{
DDRB.3=1;              
TCCR2=105; // fast PWM no clock prescale              
OCR2=128;
TIMSK=0x80;
#asm("sei")
while(1)
{
}
}