Code for the RPi

RPi/Makefile

@@ -0,0 +1,19 @@
+#
+# Makefile:
+#################################################################################
+
+
+#DEBUG  = -g -O0
+DEBUG   = -O3
+CC      = gcc
+INCLUDE = -I/usr/local/include
+CFLAGS  = $(DEBUG) -Wall $(INCLUDE) -Winline -pipe
+
+LDFLAGS = -L/usr/local/lib
+LDLIBS    = -lwiringPi -lwiringPiDev -lpthread -lm
+
+# Should not alter anything below this line
+###############################################################################
+
+SRC     =       i2c_challenge.c                                               \
+

RPi/README.md

@@ -0,0 +1,10 @@
+This is a runnable executable that sends I²C-values to a specified slave (In this case an AVR on address 0x20)
+
+On the pi you need:
+wiringpi
+gcc
+
+To compile and run:
+make i2c_challenge
+
+./i2c_challenge

RPi/i2c_challenge.c

@@ -0,0 +1,65 @@
+O/*
+*i2ctest.c
+*	Raspberry Pi I2C test using wiringPi library.
+*
+*Copyright (c) Nahid Alam. <nahid.mahfuza.alam@gmail.com>
+***********************************************************
+*i2ctest is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU Lesser General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    i2ctest is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Lesser General Public License for more details.
+ *
+***********************************************************
+*/
+
+#include <stdio.h>
+#include <wiringPi.h>
+#include <wiringPiI2C.h>
+
+int main (int argc, char *argv[])
+{
+        int fd;
+        int data;
+	int send=1;
+        wiringPiSetup () ;
+        fd=wiringPiI2CSetup (0x20) ;  /*Use i2cdetect command to find your respective device address*/
+        if(fd==-1)
+        {
+                printf("Can't setup the I2C device\n");
+                return -1;
+        }
+        else
+        {
+		while(data != 6) {
+			wiringPiI2CWrite(fd, send);
+                        data=wiringPiI2CRead(fd);
+                        if(data==-1)
+                        {
+                                printf("No data\n");
+                                //return -1;
+                        }
+			else if(data == send*3) {
+				printf("Sending challenge");
+				wiringPiI2CWrite(fd, 4);
+			}
+			else if(data == 6) {
+				printf("Read proper response \n");
+				break;
+			}
+                        else
+                        {
+                                //print data
+				printf("Waiting to send challenge");
+                        }
+                        printf(" data=%d\n", data);				
+			
+                }
+        }
+        return 0;
+}
+