TWI doesnt generate interrupt in slave mode, using micro Atmega32

[Mojtaba]

Hi all, I try to have communicate between two Atmega32. at first master should send zero to the slave, the code is:
start:
         senddata=0;
         address=10;
         master_transmitter(senddata,address);

void master_transmitter(unsigned char senddata1,unsigned char address1)
{
    TWCR=0b10100100;                                  //start condition
    while(!(TWCR &(0b10000000)));                      //wait for TWINT flag
    if((TWSR & 0xF8)==0x08 || (TWSR & 0xF8)==0x10)  //check TWSR
        {
            TWDR=((address1 << 1) & (0xFE));          //send SLA+W
            TWCR=0b10000100;
            while(!(TWCR & (0b10000000)));
        }
    if((TWSR & 0xF8)==0x18)
        {
            TWDR=senddata1;
            TWCR=0b10000100;
            while(!(TWCR & (0b10000000)));
        }
        TWCR=0b10010100;    //stop condition
}

and the slave code is:

start:
TWSR=0x00;
TWCR=0x45;
#asm(“sei”)
while(1)
    {
        if(receiveddata==0)
            {
        [do something]
        }
     }

interrupt [TWI] void twi_isr(void)
{
    unsigned char Sreg;
    Sreg=TWSR;
    switch(Sreg)
        {
            case 0x90:
                receiveddata=TWDR;
                sprintf(buff,”global:%d”,receiveddata);
                lcd_puts(buff);
                break;
            case 0x98:
                TWCR=0b10000000;
                break;
            case 0x80:
                receiveddata=TWDR;
                break;
            case 0xA8:
                TWDR=sendeddata;
                TWCR=TWCR|(0b10000000);
                break;
                
        }
        TWCR|=(0b10000000);
}

but I found that there isnt any interrupt in the slave when the master send zero to it! I really confused whit this! please help me.
 

[AJISH ALFRED]

Hi Mojtaba,

In TWI the start and stop bits have some speciality than other bits. They happen when the clock is enabled, while the data bits happen when the clock is disabled. Suggest you to learn the TWI in more detail and check it with your code.

[Ashutosh Bhatt]

follow the tutorial on TWI given for AVR micro controller on

EG labs / micro controller / AVR

[Author]

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