#include <avr/io.h>
#include <avr/eeprom.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>

#define F_CPU 1000000UL  // 1 MHz
#include <util/delay.h>


void delay_us(uint16_t t)
{
  int i;
  if (t > 10)
    for (i=0;i<t/10;i++)
      _delay_us(10);
  else
    _delay_us(t);
}

void delay_ms(uint16_t t)
{
  int i;
  if (t > 10)
    for (i=0;i<t/10;i++)
      _delay_ms(10);
  else
    _delay_ms(t);
}

int ds_reset()
{
  int r=0;
  PORTA &= ~(1<<4);
  DDRA |= (1<<4);        // DQ = 0;
  delay_us(500);        // 480us minimum
  DDRA &= ~(1<<4);        // DQ in
  delay_us(80);            // waits 15-60us and then
  r = (PINA & (1<<4));    //   capture the presence pulse (60-240us)
  delay_us(400);        
  return !r;
}

    \note When using _delay_us() and _delay_ms(), the expressions
    passed as arguments to these functions shall be compile-time
    constants, otherwise the floating-point calculations to setup the
    loops will be done at run-time, thereby drastically increasing
    both the resulting code size, as well as the time required to
    setup the loops.

#include <avr/io.h>
#include <avr/eeprom.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>

#define F_CPU 1000000UL  // 1 MHz
#include <util/delay.h>


void delay_ms(uint16_t t)
{
  uint8_t i;
  if (t > 10)
    for (i=0;i<t/10;i++)
      _delay_ms(10);
  else
    _delay_ms(t);
}

int ds_reset()
{
  uint8_t r=0;
  PORTA &= ~(1<<4);
  DDRA |= (1<<4);        // DQ = 0;
  _delay_us(480);
  DDRA &= ~(1<<4);        // DQ pull up
  _delay_us(70);
  r = (PINA & (1<<4));    // Capture the presence pulse
  _delay_us(410);        
  return !r;
}

void ds_write_bit(uint8_t b)
{
  if (b)
    {
        PORTA &= ~(1<<4);
      DDRA |= (1<<4);        // DQ = 0;
        _delay_us(6);
        DDRA &= ~(1<<4);        // DQ pull up
        _delay_us(64);    
    }
  else
    {
      PORTA &= ~(1<<4);
      DDRA |= (1<<4);        // DQ = 0;
      _delay_us(60);
      DDRA &= ~(1<<4);        // DQ pull up
      _delay_us(10);
    };
}

uint8_t ds_read_bit()
{
  uint8_t r=0;
  PORTA &= ~(1<<4);
  DDRA |= (1<<4);        // DQ = 0;
  _delay_us(6);
  DDRA &= ~(1<<4);        // DQ pull up
  _delay_us(9);
  r = (PINA & (1<<4));
  _delay_us(55);
  if (r)
    return 1;
  else
    return 0;
}

void ds_write_byte(uint8_t data)
{
  uint8_t loop;
  // Loop to write each bit in the byte, LS-bit first
  for (loop = 0; loop < 8; loop++)
    {
      ds_write_bit(data & 0x01);
      // shift the data byte for the next bit
      data >>= 1;
    }
}

uint8_t ds_read_byte()
{
  uint8_t loop, result=0;
  for (loop = 0; loop < 8; loop++)
    {
      // shift the result to get it ready for the next bit
      result >>= 1;
      // if result is one, then set MS bit
      if (ds_read_bit())
        result |= 0x80;
    }
  return result;
}

int16_t ds_read_temperature()
{
  int16_t r = -1;
  int i;
  uint8_t buf[9]={0};

  if (ds_reset())
    {
      ds_write_byte(0xCC);    //Skip ROM command
      ds_write_byte(0x44);    //Convert T command
      delay_ms(1000);        // lame :)
      ds_write_byte(0xBE);    //Read Scratchpad
      for (i=0; i < 10; i++)
        buf[i] = ds_read_byte();
      r = (buf[0] | (buf[1] << 8)) >> 4;

    };
  return r;
}

void delay_ms(uint16_t t)
{
   uint8_t i;
   if (t > 10)
      for (i=t/10;i;i--)
         _delay_ms(10);
      else
         _delay_ms(t);
}

void delay_ms(uint16_t t)
{
   uint8_t i;
   if (t >= 256)
   {
      for (i=t/256;i;i--)
         _delay_ms(256);
      t &= 255;
   }
   _delay_ms(t);
}

int ow_reset()
{
  uint8_t r=0;
  PORTA &= ~(1<<4); // +4.95В
  DDRA |= (1<<4);        // DQ = 0;
r = (PORTA & (1<<4));    //+4.28В        как такое может быть???
  _delay_us(480);
  DDRA &= ~(1<<4);        // DQ pull up
  _delay_us(70);
  r = (PORTA & (1<<4));    // Capture the presence pulse
  _delay_us(410);        
  return r;                        // +4.95В
}