/**************************************
thermo.c
Digital Thermometer -55C to +125C
AVR 90S2313 & DS1820                    

Copyright 2001 by Wichit Sirichote

**************************************/

#include <90s2313.h>
#include <math.h> 
#include <delay.h>

// 1 Wire Bus functions
#asm
   .equ __w1_port=0x12
   .equ __w1_bit=6
#endasm
#include <1wire.h>

// DS1820 temperature sensor functions
#include <ds1820.h>

// Declare your global variables here
                                             
unsigned char tick,i,digit;     
unsigned char heat[4];         
unsigned int xtimer1;
int temp,T,X1,X2,X3,X4,X5;  // signed number for negative and positve temperature manipulating               

char key;        

unsigned char convert[10] = {0x3F,0x06,0xdb,0xcf,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
#define xtal 4000000L //selbst eigefügt   
#define segment PORTB
#define LED_digit PORTD
 
                                
// converts 16-bit data in T to display buffer for both negative and positive reading

void heatToBuffer()
{
   if(T<0){
   heat[3] = 0x40;  // if negative, put -
   heat[0] = 0x39; // C        
   
   T = 34 + abs(T);   // get only amplitude (+34 selbst eingefügt)
   heat[1] =  convert[T%10];  
   heat[2] = convert[T/10];  
   if (heat[2] == 0x3f)   
       heat[2] = 0; // off msd   
                }
    else
    {
     heat[0] = 0x39; // C    
     
     heat[3] = convert[T/100];
     temp = T%100;
     heat[1] = convert[temp%10];
     heat[2] = convert[temp/10];
    // off msd     
     if (heat[3] == 0x3f)
         {
            heat[3] = 0;
            if(heat[2] == 0x3f)
             heat[2] = 0;
          }
      }                   
}
  

LPF()      // performs five-point moving average
{           
    X5=X4;
    X4=X3;
    X3=X2;
    X2=X1;
    X1= T;
    T = (X1+X2+X3+X4+X5)/5;
}
    
  
read_temp()
{                                 
    if(++xtimer1 >=5)
    {
     xtimer1 = 0;
     segment = 0xff;
       T =  (ds1820_temperature_10(0)/10)  
       LPF();    // enter filter 
       heatToBuffer();         // convert it   
    	}
}
  
 // Timer 0 overflow interrupt service routine                
 // timer interrupt every 1/15 sec provides foreground task to be run periodically.

interrupt [TIM0_OVF] void timer0_ovf_isr(void)
{           
      switch (++tick){
        case 15: tick = 0;
        read_temp(); //second_task();
         }

}

void scanLED() /* scan 4-digit LED and 4-key switch, if key pressed key = 0-3
else key = -1 */
// adapted from 89C2051 project  if needs scan key, find one bit input port   
{  
    char i;
    digit = 0x20;
    key = -1;
    for( i = 0; i < 4; i++)  /* 4-DIGIT scanning */
    {
        LED_digit = ~digit;  /* send complement[digit] */  
        segment = ~heat[i];  /* send complement[segment] */
        delay_ms(1);         /* delay a while */
        segment = 0xff;        /* off LED */
     //   if ((PORTD & 0x10) == 0) /* if key pressed P3.4 became low */
     //      key = i;       /* save key position to key variable */
        digit>>=1;        /* next digit */
    }
}              

void main(void)
{

	DDRB=0xFF;
	PORTB=0x00;
 
	DDRD=0x7F;
	PORTD=0x00;

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: 3.906 kHz
// Mode: Output Compare
// OC0 output: Disconnected
	TCCR0=0x05;
	TCNT0=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
	TIMSK=0x02;

// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;


// 1 Wire Bus initialization
w1_init();

// Global enable interrupts
#asm("sei")

// 1 Wire Bus initialization
w1_init(); 
	               
      T = 44;
      heatToBuffer();
 
while (1)
      {
       scanLED();  //  run background task forever         
       }
      

}