The 1 Wire Functions are:

unsigned char w1_init(void)


this function initializes the 1 Wire devices on the bus.

It returns 1 if there were devices present or 0 if not.

unsigned char w1_read(void)

this function reads a byte from the 1 Wire bus.

unsigned char w1_write(unsigned char data)

this function writes the byte data to the 1 Wire bus.

It returns 1 if the write process completed normally or 0 if not.

unsigned char w1_search(unsigned char cmd,void *p)

this function returns the number of devices connected to the 1 Wire bus.
If no devices were detected then it returns 0.

/*****************************************************
This program was produced by the
CodeWizardAVR V1.24.4 Standard
Automatic Program Generator
© Copyright 1998-2004 Pavel Haiduc, HP InfoTech s.r.l.
http://www.hpinfotech.com
e-mail:office@hpinfotech.com

Project :
Version :
Date    : 07.05.2002
Author  : ps1x                            
Company : sas                            
Comments:


Chip type           : ATtiny26L
Clock frequency     : 4,000000 MHz
Memory model        : Tiny
External SRAM size  : 0
Data Stack size     : 32
*****************************************************/

#include <tiny26.h>

// 1 Wire Bus functions
#asm
   .equ __w1_port=0x18;PORTB
   .equ __w1_bit=6
#endasm
#include <1wire.h>
#include <delay.h>
eeprom char *temp;
// External Interrupt 0 service routine
interrupt [EXT_INT0] void ext_int0_isr(void)
{
// Place your code here

}

// Timer 0 overflow interrupt service routine
interrupt [TIM0_OVF] void timer0_ovf_isr(void)
{
// Place your code here

}

// Declare your global variables here

void main(void)
{
unsigned char devices,rom[9];


// Declare your local variables here

// Input/Output Ports initialization
// Port A initialization
// Func7=Out Func6=Out Func5=Out Func4=Out Func3=Out Func2=Out Func1=Out Func0=Out
// State7=0 State6=0 State5=0 State4=0 State3=0 State2=0 State1=0 State0=0
PORTA=0xFF;
DDRA=0xFF;

// Port B initialization
// Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In
// State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T
PORTB=0x00;
DDRB=0x00;

// Timer/Counter 0 initialization
// Clock source: System Clock
// Clock value: 3,906 kHz
TCCR0=0x00;
TCNT0=0x00;

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: Timer 1 Stopped
// Mode: Normal top=FFh
// OC1A output: Disconnected
// OC1B output: Disconnected
PLLCSR=0x00;
TCCR1A=0x00;
TCCR1B=0x00;
TCNT1=0x00;
OCR1A=0x00;
OCR1B=0x00;
OCR1C=0x00;

// External Interrupt(s) initialization
// INT0: On
// INT0 Mode: Falling Edge
// Interrupt on any change on pins PA3, PA6, PA7 and PB4-7: Off
// Interrupt on any change on pins PB0-3: Off
GIMSK=0x00;
MCUCR=0x00;
GIFR=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x00;

// Universal Serial Interface initialization
// Mode: Disabled
// Clock source: Register & Counter=no clk.
// USI Counter Overflow Interrupt: Off
USICR=0x00;

// Analog Comparator initialization
// Analog Comparator: Off
ACSR=0x80;

// 1 Wire Bus initialization
w1_init();

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

while (1)                                              
      {                          
      devices=w1_search(0x33,rom);
      if (devices){PORTA=0x00;delay_ms(1000);PORTA=0xFF;*temp=rom;}
      // Place your code here

      };
}

   A 4.7k PULLUP RESISTOR MUST BE CONNECTED
   BETWEEN DATA (PA6) AND PORTA HEADER PIN 10 (VTG) !

TERM:CLR TR0
JB DATA,$
MOV TH0,#HI(R_DEL)
MOV TL0,#LO(R_DEL)
SETB TR0
WAIT:JNB DATA,$
SJMP TERM

RES:      JNB DATA,$

MOV R3,#14
DJNZ R3,$;delay 30 uS
CLR DATA;presence pulse begin

MOV R3,#58
DJNZ R3,$;delay 120 uS
SETB DATA;presence pulse end

MOV R0,#FAM_CODE-1;pointer load
MOV R1,#9;load number of bytes (1 RX + 8 TX)
MOV R2,#8;load number of bits
SETB RXF;set RX flag
MOV A,#0FFH;perform RX
RRC A;C <- first TX bit
CLR IE0;clear interrupt flag

;1-Wire RX-TX Loop:

LOOPH:JNB IE0,$;wait for interrupt flag

MOV DATA,C;DATA <- C
MOV TH0,#HI(R_DEL)
MOV TL0,#LO(R_DEL)
SETB TR0;start timer 0 (reset timeout)
MOV R3,#9
DJNZ R3,$;delay
MOV C,DATA;receive data bit
SETB DATA;DATA <- 1 (30uS is over)
RRC A;save received bit in ACC

CLR IE0;clear interrupt flag
DJNZ R2,LOOP;advance bit counter
JNB RXF,NEXT;jump if TX cycle

CLR RXF
CJNE A,#033H,MISM;RX complete, check command code
SJMP NEXT
MISM:CJNE A,#00FH,TERM

NEXT:INC R0;advance pointer
MOV R2,#8;bits counter reload
MOV A,@R0
RRC A
DJNZ R1,LOOP
SJMP TERM

LOOP:     JNB DATA,$;wait for DATA = 1
CLR TR0
SJMP LOOPH

;TIMER0 Interrupt Holder:
;Timer terminates process if reset pulse detected

TIMER:CLR TR0;timer 0 stop
MOV SP,#STACK
MOV A,#LO(RES)
PUSH ACC
MOV A,#HI(RES)
PUSH ACC
RETI;return to RES

.END