ATTiny2313 mit ATMega32 über SPI

/*

 * SPI_Master.c

 *

 * Created: 06.07.2013 21:05:31

 *  Author: Jens

 */ 

// This program is for the SPI-Master on an ATMega device

#include <avr/io.h>

#include <util/delay.h>

// Initialize the SPI-Interface

void init_spi()

{

  //Set MOSI, clock pin and SS pin as output.  Not using

  //  the SS pin at this point.

  DDRB = (1<<DDB4) | (1<<DDB5) | (1<<DDB7);

  //Enable SPI mode, master and F_CPU/16.  Slowed it down so

  //  could see what is going on with scope.

  SPCR = (1<<SPE) | (1<<MSTR) | (1<<SPR0);

}

// Send data via SPI

void send_spi(int data)

{

  // Load the data into the data register

  SPDR = data;

  // Wait until data is transmitted

  while(!(SPSR & (1<<SPIF)));

  // Wait 500ms before sending the next Byte

  _delay_ms(500);

}

int main(void)

{

  int data;

  // Set LED-Port PB2 and PB3 as output

  DDRB = (1<<DDB3) | (1<<DDB2);

  init_spi();

  data = '5';

  // Send 5, 6, 5, 6, 5, ...

    while(1)

    {

         if(data == '5')

     {

      // Send '5' and turn on LED1 and off LED2

      send_spi(data);

      data = '6'; 

      PORTB = (1<<PB3);

      PORTB &= ~(1<<PB2);

     }

     else

     {

      // Send '6' and turn on LED2 and off LED1

      send_spi(data);

      data = '5'; 

      PORTB = (1<<PB2);

      PORTB &= ~(1<<PB3);

     }

    }

  return 0;

}

/*

 * SPI_Slave.c

 *

 * Created: 07.07.2013 10:59:29

 *  Author: Jens

 */ 

// This program is for an SPI-Slave Tiny device

#include <avr/io.h>

#include <avr/interrupt.h>

#include <util/delay.h>

int data;

// Initialize SPI-Interface

void init_spi()

{

  // Set DO as output and DI, USCK as input

  DDRB = (1<<DDB6);

  DDRB &= ~(1<<DDB5) | ~(DDB7);

  // Set 3-wire-mode and external positive clock

  USICR = (1<<USIWM0) | (1<<USICS1);

  // Set the counter-overflow flag

  USISR = (1<<USIOIF);

  // Enable interrupt for counter-overflow when data is received

  USISR = (1<<USISIF);

}

ISR(USI_OVERFLOW_vect) 

{

  // Wait for reception complete 

  while(!(USISR & (1<<USIOIF)));

  // Return data register

  data = USIDR;

}

int main(void)

{

  // Set LED-Ports PB2 (LED1) and PB3 (LED2) as output

  DDRB = (1<<DDB2) | (1<<DDB3);

  init_spi();

  // If data is received via SPI, check if it is an '5' or an '6'. 

  // Then turn on the corresponding LED

    while(1)

  {  

    // Check if "data" includes an '5' -> Turn on LED1 PB2

    if(data == '5')

    {

        PORTB = (1<<PB2);

        PORTB &= ~(1<<PB3);

    }

    // Check if "data" includes an '6' -> Turn on LED2 PB3

    else if(data == '6')

    {

        PORTB = (1<<PB3);

        PORTB &= ~(1<<PB2);

    }

    }

  return 0;

}