ELAB-RFID-I2C/AVR/main.c

/* I2C Echo Example */
#include "../avr-i2c-slave/I2CSlave.h"
#include <util/delay.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#define I2C_ADDR 0x20

volatile uint8_t data;
volatile uint8_t send=0;
void I2C_received(uint8_t received_data)
{
  data = received_data;
}

void I2C_requested() {
  I2C_transmitByte(send);
}
void I2C_challenge() {
  I2C_transmitByte(send);
}

void setup() {
  // set received/requested callbacks
  I2C_setCallbacks(I2C_received, I2C_requested);

  // init I2C
  I2C_init(I2C_ADDR);
  // init output gpio
  DDRC = 0b00000100;  // PC2
  TCNT1 = 0;
  TCCR1B |= (1 << CS10) | (1 << CS11); // No prescaling

}
int main() {
  setup();
  int challenge = 0;
  unsigned int i = 0;
  // Main program loop
  while(1) {
  	if(data == 1) {
		i = TCNT1;
		srand(i);
		send = rand();
	  while(data != send+3) {
  		I2C_challenge();
	  }
	  send = 17;
	  I2C_challenge();
	  PORTC |= 2<<1;			
	  _delay_ms(5000);
	  PORTC = 0;		 
	  data = 0;

}/*	else {		
		send = 0;
		I2C_challenge();
	}*/
  }
}