Pi2c

Pi2c is a C++ is a class which allows for easy communication to an Arduino from the Raspberry Pi over the I2C bus.

Version: 1

Compiling

Pi2c is already compiled for Raspbian running on the Raspberry Pi. If you want to compile it for another system, you just need to run:

g++ -c pi2c.cpp

You may find you need to install i2c-tools in order for it to compile and it's a useful set of tools to have anyway in order help with problems on the I2C Bus.

Using Pi2c

In order to use this on a Raspberry Pi running Raspbian, you just need to copy pi2c.h and pi2c.o into your project and then include the header in your program. You then need to add the object to your compile command. eg.

g++ pi2c.o test.cpp -o test

###Example Usage###

Example C++ file:

#include "pi2c.h"

int main(){
    Pi2c arduino(7); //Create a new object "arduino" using address "0x07"
    char receive[16]; //Create a buffer of char (single bytes) for the data

    //Receive from the Arduino and put the contents into the "receive" char array
    arduino.i2cRead(receive,16);
     //Print out what the Arduino is sending...
    std::cout << "Arduino Says: " << receive << std::endl;

    //Send an 16 bit integer
    arduino.i2cWriteArduinoInt(4356);

    return 0;
}

Example Arduino file:

#include <Wire.h>

void setup() {
  Serial.begin(9600);// open the serial port at 9600 bps:
  Wire.begin(0x07); //Set Arduino up as an I2C slave at address 0x07
  Wire.onRequest(requestEvent); //Prepare to send data
  Wire.onReceive(receiveEvent); //Prepare to recieve data
}

void loop() {
}

void requestEvent()
{
  unsigned char char_ar[16] = "Hi Raspberry Pi"; //Create String
  Wire.write(char_ar,16); //Write String to Pi.
}

void receiveEvent(int numBytes){
  //Set Up Vars
  int receive_int=0;
  int count=0;

  //We'll recieve one byte at a time. Stop when none left
  while(Wire.available())
  {
    char c = Wire.read();    // receive a byte as character
    //Create Int from the Byte Array
    receive_int = c << (8 * count) | receive_int;
    count++;
  }
  //Print the Int out.
  Serial.print("Received Number: "); 
  Serial.println(receive_int);
}