#include <util/delay.h>

#define ADDR_DDR DDRA
#define ADDR_PORT PORTA
#define ADDR_PIN PINA

uint8_t get_one_address(int pin) {
  uint8_t result = 0;

  ADDR_DDR &= ~(1<<pin);    // set pin to input
  ADDR_PORT &= ~(1<<pin);   // disable internal pull-up
  _delay_ms(1);
  if (ADDR_PIN & (1 << pin)) {
    result = 2;         // pin set high
  } else {          // is pin set low or floating?
    ADDR_PORT |= (1<<pin);  // enable internal pull-up
    _delay_ms(0.1);     // see Tiny44A datasheet, 10.1.4
    if (ADDR_PIN & (1<<pin)) {  // ... is pin floating?
      result = 0;       // pin floating
    } else {
      result = 1;       // pin forced low
    }
    ADDR_PORT &= ~(1<<pin); // disable internal pull-up
  }
  return result;
}