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/*****************************************************
Chip type               : ATmega16
Program type            : Application
AVR Core Clock frequency: 16,000000 MHz
Memory model            : Small
External RAM size       : 0
Data Stack size         : 256
*****************************************************/

#include <mega16.h>
#include <delay.h>
#define ACK                    0xD0
#define NACK                   0xD1



//Функции аппаратного I2C

void start_twi(void)                                                                 
{
   TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
   while (!(TWCR & (1<<TWINT))); 
}

void stop_twi(void)   
{
   TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
}
       
void write_twi(unsigned char data_byte)
{
   TWDR = data_byte;                             
   TWCR = (1<<TWINT) | (1<<TWEN); 
  while(!(TWCR & (1<<TWINT)));     
}


unsigned char i2read (unsigned ACK_Status)
{
   if(ACK_Status == ACK)                             
     TWCR = (1<<TWINT)| (1<<TWEA) | (1<<TWEN);     
      else                                         
        TWCR = (1<<TWINT)  | (1<<TWEN);             
                                                   
  while(!(TWCR & (1<<TWINT)));
  return TWDR;
}








void main(void)
{
DDRD=0xFF;
TWBR=0xC;


start_twi();
write_twi(0x90);
write_twi(0xAC);
write_twi(0x00);
stop_twi();


start_twi();
write_twi(0x90);
write_twi(0xEE);
stop_twi();


while(1)
{
delay_ms(1000);
start_twi();
write_twi(0x90);
write_twi(0xAA);   
start_twi();
write_twi(0x91);
i2read (ACK);
i2read (NACK);
stop_twi();



}

}

start_twi();
write_twi(0x90);
write_twi(0xAC);
write_twi(0x00);
stop_twi();

start_twi();
write_twi(0x90);
write_twi(0xEE);
stop_twi();

start_twi();
write_twi(0b10010000);