New version with PRNG numbers for challenge response

AVR/main.c

@@ -1,48 +1,59 @@
 /* I2C Echo Example */
-#include "../I2CSlave/I2CSlave.h"
-
+#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 final;
+volatile uint8_t send=0;
 void I2C_received(uint8_t received_data)
 {
   data = received_data;
 }
 
-void I2C_requested()
-{
-  I2C_transmitByte(data);
+void I2C_requested() {
+  I2C_transmitByte(send);
 }
 void I2C_challenge() {
-  I2C_transmitByte(data*3);
+  I2C_transmitByte(send);
 }
 
-void setup()
-{
+void setup() {
   // set received/requested callbacks
   I2C_setCallbacks(I2C_received, I2C_requested);
 
   // init I2C
   I2C_init(I2C_ADDR);
   // init output gpio
-  DDRB = 0b00000001;  
-}
+  DDRC = 0b00000100;  // PC2
+  TCNT1 = 0;
+  TCCR1B |= (1 << CS10) | (1 << CS11); // No prescaling
 
-int main()
-{
+}
+int main() {
   setup();
-
+  int challenge = 0;
+  unsigned int i = 0;
   // Main program loop
   while(1) {
-	if(data != 4) {
+  	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();
-	}
-	else {
-		//PORTB |= 1<<1;			
-		data = 2;
-		I2C_requested();
-		 
-	}
+	}*/
   }
 }

AVR/makefile

@@ -9,7 +9,7 @@ MCU = atmega328p
 FORMAT = ihex
 TARGET = main
 SRC = $(TARGET).c \
-	I2CSlave.c
+	../avr-i2c-slave/I2CSlave.c
 ASRC = 
 OPT = s