////// 1wire.c fontion ////// 
///// DS18b20 data pin connected to  pic16f628 B0 pin ////// 



/***********************1Wire Class***********************/ 
/*Description: This class handles all communication */ 
/* between the processor and the 1wire */ 
/* sensors. 
/*********************************************************/ 

/*-------1-wire definitions-------*/ 
#define ONE_WIRE_PIN PIN_A0

/*******************1-wire communication functions********************/ 


void onewire_reset()  // OK if just using a single permanently connected device 
{ 
output_low(ONE_WIRE_PIN); 
delay_us( 500 ); // pull 1-wire low for reset pulse 
output_float(ONE_WIRE_PIN); // float 1-wire high 
delay_us( 500 ); // wait-out remaining initialisation window. 
output_float(ONE_WIRE_PIN); 
} 

/*********************** onewire_write() ********************************/ 
/*This function writes a byte to the sensor.*/ 
/* */ 
/*Parameters: byte - the byte to be written to the 1-wire */ 
/*Returns: */ 
/*********************************************************************/ 

void onewire_write(int data) 
{ 
int count; 

for (count=0; count<8; ++count) 
{ 
  output_low(ONE_WIRE_PIN); 
  delay_us( 2 ); // pull 1-wire low to initiate write time-slot. 
  output_bit(ONE_WIRE_PIN, shift_right(&data,1,0)); // set output bit on 1-wire 
  delay_us( 60 ); // wait until end of write slot. 
  output_float(ONE_WIRE_PIN); // set 1-wire high again, 
  delay_us( 2 ); // for more than 1us minimum. 
} 
} 

/*********************** read1wire() *********************************/ 
/*This function reads the 8 -bit data via the 1-wire sensor. */ 
/* */ 
/*Parameters: */ 
/*Returns: 8-bit (1-byte) data from sensor */ 
/*********************************************************************/ 

int onewire_read() 
{ 
int count, data; 

for (count=0; count<8; ++count) 
{ 
  output_low(ONE_WIRE_PIN); 
  delay_us( 2 ); // pull 1-wire low to initiate read time-slot. 
  output_float(ONE_WIRE_PIN); // now let 1-wire float high, 
  delay_us( 8 ); // let device state stabilise, 
  shift_right(&data,1,input(ONE_WIRE_PIN)); // and load result. 
  delay_us( 120 ); // wait until end of read slot. 
} 

return( data ); 
}