#include <xc.h>
#include <pic12f683.h>
#include <stdint.h>

#define _XTAL_FREQ   6000000
#define Baudrate              1200                      //bps
#define OneBitDelay           (1000000/Baudrate)
#define DataBitCount          8                         // no parity, no flow control
#define UART_RX               GPIO,GP3					// UART RX pin
#define UART_TX               GPIO,GP1					// UART TX pin
#define SCL     GPIO,GP0
#define SDA     TRISIO2
#define SCL_IN  GPIO,GP0
#define SDA_IN  GPIO,GP2
#define TMR0_2 (TMR0 & 1<<2)
#define LM75AD 0b10010000

#pragma config "FOSC=EC"
#pragma config "WDTE=OFF"
#pragma config "PWRTE=ON"
#pragma config "MCLRE=OFF"
#pragma config "CP=OFF"
#pragma config "CPD=OFF"
#pragma config "BOREN=OFF"

   unsigned char count;
   unsigned char tempmsb;
   unsigned char templsb;
   unsigned char tempBCD1;
   unsigned char tempBCD2;
   unsigned char loop;	
   unsigned char SEC;
   unsigned char DATARDY;
   unsigned char Tick,Long;
   unsigned char DataValue;
   unsigned char TXENABLE;
   unsigned char i;
   unsigned char shift;





void i2c_dly(void)
{
_delay(50);
}


void i2c_start(void)
{
SDA = 1;
i2c_dly();
SCL = 1;
i2c_dly();
SDA = 0;
GPIO = 0b11011;
i2c_dly();
SCL = 0;
i2c_dly();
}

void i2c_stop(void)
{
  SDA = 0;
  GPIO = 0b11010;           // i2c stop bit sequence
  i2c_dly();
  SCL = 1;
  i2c_dly();
  SDA = 1;
  i2c_dly();
}

bit i2c_tx(unsigned char d)
{
char x;
static bit b;
  for(x=8; x; x--) {
    if(d&0x80) SDA = 1;
    else SDA = 0;
	i2c_dly();
	GPIO = 0b11010;
	i2c_dly();
	SCL = 1;
    i2c_dly();
	d <<= 1;
    SCL = 0;
	i2c_dly();
  }
  SDA = 1;
  i2c_dly();
  SCL = 1;
  i2c_dly();
  b = SDA_IN;          // possible ACK bit
  i2c_dly();
  SCL = 0;
  i2c_dly();
  return b;
}

unsigned char i2c_rx(char ack)
{
unsigned char x, d=0;
 SDA = 1;
 i2c_dly(); 
  for(x=0; x<8; x++) {
    d <<= 1;
    SCL = 1;
    i2c_dly(); 
    if(SDA_IN) d |= 1;
	i2c_dly();
	SCL = 0;
	i2c_dly();
  } 
  if(ack) SDA = 0;
  else SDA = 1;
  i2c_dly();           // send (N)ACK bit
  SCL = 1;
  i2c_dly();
  SCL = 0;		
  SDA = 1;
  return (d) ;
}



void InitSoftUART(void)		// Initialize UART pins to proper values
{
	UART_TX = 1;			// TX pin is high in idle state
	
}

void interrupt isr(void)
{
asm("nop");
asm("nop");
asm("nop");
asm("nop");
asm("nop");
asm("nop");
asm("nop");
asm("nop");
asm("nop");


	if(T0IF)
	{
		TMR0=205;
		T0IF = 0;
		GIE= 1;
		loop--;
	}
	if (loop==0)
	{
		loop=200;
		Long--;
		if (Long==0)
		{	
			SEC++;
			Long=6;
		}
	}

	if (TXENABLE==1)
	{
		if (i==0)
		{
			UART_TX = 0;
		}
		else if (i==9)
		{
			UART_TX = 1;
			i=0;
			TXENABLE=0;
		}	
		
		if(i>0 & i<9)
		{
			shift = i-1;
			if( ((DataValue>>shift) &0x1) == 0x1 )	
				{
				UART_TX = 1;
				}
				else      //if Bit is low
				{
				UART_TX = 0;
				}
		}
		i++;
	}
			
		
	
}
void main()
{
	unsigned char ch = 0;
	i=0;
	ADCON0=0;
	ANSEL=0;
	CMCON0=7;
	VRCON = 0b00000000;
	TRISIO = 0b10100;
	GPIO = 0b10011;	
	T0CS = 0;  // bit 5  TMR0 Clock Source Select bit...0 = Internal Clock (CLKO) 1 = Transition on T0CKI pin
	T0SE = 0;  // bit 4 TMR0 Source Edge Select bit 0 = low/high 1 = high/low
	PSA = 0;   // bit 3  Prescaler Assignment bit...0 = Prescaler is assigned to the Timer0
	PS2 = 0;   // bits 2-0  PS2:PS0: Prescaler Rate Select bits
	PS1 = 1;
	PS0 = 1;
	TMR0 = 178;             // preset for timer register


	T0IE = 1;
	PSA = 0;
    PEIE = 1;
	GIE = 1;


	TXENABLE = 0;
   	tempmsb=0;
   	templsb=0;
	count=0;
	Tick=200;
	Long= 6;
	SEC=0;
	loop=200;
	//T0IE=1;
	//GIE=1;			
	InitSoftUART();  	
   while(1)
   {


		if (SEC==30)
		{
		SEC=0;
		i2c_dly;
		
		//Set Pointer to the Temperature Register
		i2c_start();
		i2c_tx(0b10010000);
		i2c_tx(0b00000000);
		i2c_start();
		i2c_tx(0b10010001);
		tempmsb=i2c_rx(1);
		templsb=i2c_rx(0);
		i2c_stop();
		tempmsb=tempmsb;
		tempBCD1=(tempmsb/10) + 48;
		tempBCD2=(tempmsb % 10) + 48;

				
		DataValue = 'T';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'e';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'm';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'p';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'e';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'r';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'a';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 't';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'u';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'r';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = 'e';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = ' ';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = '=';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		DataValue = ' ';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		
		DataValue = tempBCD1;
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		
 		DataValue = tempBCD2;
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		

		DataValue = '\r';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		
		DataValue = '\n';
		i=0;
		TXENABLE=1;
		__delay_ms(50);
		

		__delay_ms(300);
		}
	}
}