AVRFreaks.net

if(usiTwiDataInReceiveBuffer())
{
  temp = usiTwiReceiveByte();

  switch (temp)
  {
    case 1: led(LED1, 1); break;
    case 2: led(LED2, 1); break;
    case 3: led(LED3, 1); break;

    usiTwiTransmitByte(distance);
  }
 //       usiTwiTransmitByte(distance);
 }

#include <avr/io.h>
#include <avr/interrupt.h>
#include "usiTwiSlave.h"

// TWI Slave defines
#define TWI_SLA 0x07  // Slave Address
int main(void)
    {
    unsigned char temp = 0;
    DDRA = 0x07; // set ddra as output

    // Own TWI slave address
    usiTwiSlaveInit(TWI_SLA);
    sei( );

    for (;;)
   {
   if (usiTwiDataInReceiveBuffer())
       {
       temp = usiTwiReceiveByte();
       }
   PORTA = temp; // activate a few leds to visualize the data
   }
    return 0;
    }

//Includes
#include <avr/io.h>
#include <avr/interrupt.h>
#include "twi.c"

//defines
#define Slave 0x07

// Globales Variables
uint8_t data;

//main
int main(void)
    {
    DDRB = 0xff; // Port B as Output
    PORTB |= (1 << PB4);

    data = 0x02; //initilize data
    twiInit(10); //init twi
    sei( );

    while (1)
   {
   //twiWrite(Slave,&data,1);
   if (twiStart(Slave, TW_WRITE)) // 0 = error , non 0 = ok
       {
       PORTB &= ~(1 << PB4);
       PORTB |= (1 << PB1);
       twiStop();
       PORTB &= ~(1 << PB1);
       }
   else
       {
       PORTB &= ~(1 << PB4);
       PORTB |= (1 << PB2);
       twiWriteBytes(&data, 1);
       twiStop();
       PORTB &= ~(1 << PB2);
       }
   }
    return 0;
    }

usiTwiDataInTransmitBuffer()

   case USI_SLAVE_SEND_DATA:
      // Get data from Buffer
      if ( txHead != txTail )
      {
         txTail = ( txTail + 1 ) & TWI_TX_BUFFER_MASK;
        USIDR = txBuf[ txTail ];
      }
      else
      {
        // the buffer is empty
        SET_USI_TO_READ_ACK( );
        SET_USI_TO_TWI_START_CONDITION_MODE( );
        return;
      } // end if
      overflowState = USI_SLAVE_REQUEST_REPLY_FROM_SEND_DATA;
      SET_USI_TO_SEND_DATA( );
      break;

#include <Wire.h>

void setup()
{
  Wire.begin();        // join i2c bus (address optional for master)
  Serial.begin(9600);  // start serial for output
  Serial.println("Initializing");
}

void loop()
{
  Wire.beginTransmission(0x26);
  Wire.send(120);
  Wire.endTransmission();
 
  Wire.requestFrom(0x26, 1);    // request 6 bytes from slave device #2

  while(Wire.available())    // slave may send less than requested
  {
    char c = Wire.receive(); // receive a byte as character
    Serial.print("Received:");
    Serial.println(c);         // print the character
  }

  delay(500);
}

#include <avr/io.h>
#include <avr/interrupt.h>
extern "C"
{
        #include "usiTwiSlave.h"
}

int main(void)
{
   unsigned char slaveAddress, temp;

        sei(); // enable interupts

   slaveAddress = 0x26;
        usiTwiSlaveInit(slaveAddress);

   for(;;)
        {
      if(usiTwiDataInReceiveBuffer())
          {
          temp = usiTwiReceiveByte();
         usiTwiTransmitByte(120);
      }
      asm volatile ("NOP" ::);
   }
}