#define ONEPIN       PINC // PIN register
#define ONEDDR       DDRC // Data Direction Register
#define ONEPORT      PORTC// PORT

unsigned char OneWireReset(unsigned char mask)
{
ONEPORT &= ~(mask);                 // Normal input no pull up
if (ONEPIN == 0) return 0;        // detect 0V on buss error
ONEDDR |= mask;                        // out at 0
  delay_us(500);
ONEDDR &= ~(mask);                  // Set to input
  delay_us(70);
if ((ONEPIN & mask) == 0)
   {
     delay_us(500);
   return mask;
   }
mask&=~ONEPIN;  
  delay_us(500);
return mask;
}