#include <mega32a.h>
#include <delay.h>
// Declare your global variables here

void expander(unsigned char adresa, unsigned char data1, unsigned char data2);

void main(void)
{
PORTA=0xFF;
DDRA=0xFF;

PORTD=0xFF;
DDRD=0xFF;

// Analog Comparator initialization
// Analog Comparator: Off
// Analog Comparator Input Capture by Timer/Counter 1: Off
ACSR=0x80;
SFIOR=0x00;

////////////////////// n a s t a v e n i   i 2 c //////////////////////
TWSR=0x00;      // pro 60 kHZ
TWBR=0x48;      // cca 60 kHz =0x7e   (pri 16 MHHz)
TWAR=0x40;      // sl.adrres 20 + 0
TWCR=0x44;      // enable TWI + enable ACK
/*
TWDR - data to transmit
TWCR - START/STOP
TWSR - 7...3 bity urcuji stav
*/
///////////////////////////////////////////////////////////////////////

delay_ms(5);
expander(0x06,0x00,0x00);
delay_ms(5);
expander(0x00,0x00,0xFF);

while (1)
      {
                         
      }
}

void expander(unsigned char adresa, unsigned char data1, unsigned char data2)
{
TWCR=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);  //START
while (!(TWCR&(1<<TWINT)));            //START poslan
if ((TWSR & 0xF8) == 0x08)             //kontrola stavu START
    {
    PORTD.7=0;
    }

TWDR=0x40;                              //slave adresa + 0
TWCR = (1<<TWINT) | (1<<TWEN);          //TWIN = 1 (vzdy), start prenosu
while (!(TWCR & (1<<TWINT)));           //poslano
delay_us(12);
if ((TWSR & 0xF8) == 0x18)              //kontrola stavu "prijato"
    {
    PORTD.6=0;
    }

TWDR=adresa;                             //adresa registru v exp.
TWCR = (1<<TWINT) | (1<<TWEN);          //TWIN = 1 (vzdy), start prenosu
while (!(TWCR & (1<<TWINT)));           //poslano
delay_us(12);
if ((TWSR & 0xF8) == 0x28)              //kontrola stavu "prijato"
    {
    PORTA.0=0;
    }

TWDR=data1;                              //hodnota 1
TWCR = (1<<TWINT) | (1<<TWEN);          //TWIN = 1 (vzdy), start prenosu
while (!(TWCR & (1<<TWINT)));           //poslano
if ((TWSR & 0xF8) == 0x28)              //kontrola stavu "prijato"
    {
    PORTA.1=0;
    }
delay_us(12);

TWDR=data2;                              //hodnota 2
TWCR = (1<<TWINT) | (1<<TWEN);          //TWIN = 1 (vzdy), start prenosu
while (!(TWCR & (1<<TWINT)));           //poslano
delay_us(12);
if ((TWSR & 0xF8) == 0x28)              //kontrola stavu "prijato"
    {
    PORTA.2=0;
    }
    
delay_us(12);
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO); //STOP
delay_us(12);
}