AVRFreaks.net

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

// --> PORTF
#define BCD_A          PF0
#define BCD_B               PF1
#define BCD_C          PF2
#define BCD_D               PF3
#define TEMP               PF4

// --> PORTG
#define DIGI5_EN       PG3
#define DIGI6_EN            PG4

void initialization();


int main(void)
{
   initialization();
   
   ADCSRA |= ( 1 << ADSC );
   
    while(1)
    {   
      
    }
}

//********************************************************//
void initialization()
{
   cli();

   DDRF |= ( 1 << BCD_A ) | ( 1 << BCD_B ) |
                ( 1 << BCD_C ) | ( 1 << BCD_D ); 
            // Enable first 4 bits of portF as O/P
   
      DDRG |= ( 1 << DIGI5_EN ) | ( 1 << DIGI6_EN );
      PORTG |= ( 1 << DIGI5_EN ) | ( 1 << DIGI6_EN );
   
   // initialize ADC
   ADCSRA |= ( 1 << ADPS0 ) | ( 1 << ADPS1 )|
                  ( 1 << ADPS2 );
           // adjust prescaler (for 128)

   ADMUX |= ( 1 << REFS0 ) | ( 1 << MUX2);      //choose AVCC as a voltage reference and channel ADC4
   
        ADCSRA |= ( 1 << ADEN );                   
                // Enable ADC
   ADCSRA |= ( 1 << ADFR);           
               // choose free running mode
   ADCSRA |= ( 1 << ADIE);
               // ADC interrupt Enable
   
   sei();
}

//********************  Interrupts *********************//
ISR (ADC_vect)
{
   
   if ( ADCL > 200 )
   PORTF = 0x09;
   else if ( ADCL > 150 )
   PORTF = 0x08;
   else if ( ADCL > 120 )
   PORTF = 0x07;
   else if ( ADCL > 100 )
   PORTF = 0x06;
   else if ( ADCL > 80 )
   PORTF = 0x05;
   else if ( ADCL > 60 )
   PORTF = 0x04;
   else if ( ADCL > 50 )
   PORTF = 0x03;
   else if ( ADCL > 20 )
   PORTF = 0x02;
   else if ( ADCL > 4 )
   PORTF = 0x01;
}

ISR (ADC_vect)
{
   unsigned int result = ADCW;    // read all 10 bits
   if ( result > 200 )
   PORTF = 0x09;
   else if ( result > 150 )
   PORTF = 0x08;
   ...

else
PORTF = 0x00;

//----struct used for rolling average------
#define NUMSAMP 32
typedef struct{
  char ndx;
  long int  tot;
  int  avg;
  int  dat[NUMSAMP]; //avg over NUMSAMP readings
}Trollavg;

Trollavg rollavg[8];
unsigned int addat[8];  //internal 10 bit
int avg;
float ad2volts;
float volts,volts2degC,degC,degF;
.
.
.
//--------------------
void adc_init(void){
//ADC initialize

  ADCSRA = 0x00; //disable adc
  ADMUX  = 0x40; //select vcc and adc input 0
  ACSR   = 0x80;
  ADCSRA = 0x87;
  DIDR0  = 0x3f; //digital input disable portc 543210
}

//--------------------
void initrollavg(Trollavg *p){
//init rollavg struct
char i;

  p->ndx=0;
  p->tot=0;
  p->avg=0;
  for(i=0; i < NUMSAMP; i++){
    p->dat[i]=0;
  } 
}

//--------------------
int calcrollavg(Trollavg *p, int w){
//return rollavg of last NUMSAMP readings

  p->tot-=p->dat[p->ndx]; //subtract old value from tot
  p->tot += w;            //add in new value
  p->dat[p->ndx++]=w;     //remember new value, bump ndx
  if(p->ndx==NUMSAMP) p->ndx=0; //rewind
  p->avg = p->tot >> 5;   //2^5=32=NUMSAMP; avg is tot/NUMSAMP
  return p->avg;
}

//---------------------
unsigned int readadchan(char n){
//read ch n of internal a/d  10 bit unsigned

  ADMUX= 0x40 + n; //select vcc + channel n
  ADCSRA |= 0x40;  //init conversion
  while((ADCSRA & 0x40) != 0){}; //wait for conv complete
  return ADC;
}

//------------------
void temploop(void){
//read LM35 temp sensor on ad chan 3
//10mv/deg C-> 100degc=1000mv-> 100 degC/volt
char c;

  cprintf("temploop  q=quit\n");
  ad2volts=5.0/1023.0; //5v=1023
//  cprintf("ad2volts %#7.3f \n",ad2volts);
  volts2degC=10.0;
  cprintf("ad   V       degC    degF \n");
  c=0;
  while(c != 'q'){
    if(kbhit()){
      c=getchar();
    } 
    addat[3]=readadchan(3);
    avg = calcrollavg(&rollavg[3],addat[3]);
    volts = avg*ad2volts;
    degC = volts*volts2degC;
    degF = degC * 1.8 + 32.0;
    cprintf("%4d %#7.3f %#7.1f %#7.1f \r",addat[3],volts,degC,degF); //
  }
}