File content as of revision 2:a8bbf677e774:

/**
 * @file   : communication.h (1.0)
 * @brief  : manage communication
 * @author : Shinnosuke KOIKE
 * @date   : 2015/08/06
 */

#ifndef COMMUNICATION_H
#define COMMUNICATION_H

#include "mbed.h"

class CommuMaster {
public:
    CommuMaster(PinName sda, PinName scl);
    void receiveData(int correctFrequency, char addr, char data[], char length);

private:
    I2C* i2cmaster;
};

class CommuSlave {
public:
    CommuSlave(PinName sda, PinName scl);
    void sendData(int correctFrequency, char addr, char data[], char length);

private:
    I2CSlave* i2cslave;
};

// initialize
CommuMaster::CommuMaster(PinName sda, PinName scl) {
    i2cmaster = new I2C(sda, scl);
}

// receive some data
void CommuMaster::receiveData(int correctFrequency, char addr, char data[], char length) {
    i2cmaster->frequency(correctFrequency);
    i2cmaster->read(addr | 1, data, length, false);
}

// initialize
CommuSlave::CommuSlave(PinName sda, PinName scl) {
    i2cslave = new I2CSlave(sda, scl);
}

// send some data
void CommuSlave::sendData(int correctFrequency, char addr, char data[], char length) {
    i2cslave->frequency(correctFrequency);
    i2cslave->address(addr);
    i2cslave->write(data, length);
}

#endif

/**
 * example program(master)

#include "mbed.h"

#define DATA_NUM    8

int main(void) {
    CommuMaster master(D5, D6);
    char addr = 0xA0;
    int  freq = 2000;
    char data[DATA_NUM];
    char length = 8;

    while (1) {
        master.receiveData(freq, addr, data, length);
        for (int i = 0; i < DATA_NUM; i++) {
            pc.printf("%d ", data[i]);
        }
        pc.putchar('\n');
    }
}

 * example program(slave)

#include "mbed.h"

int main(void) {
    CommuSlave slave(D5, D6);
    char addr = 0xA0;
    int  freq = 2000;
    char data[8] = {1, 1, 0, 0, 0, 0, 0, 1};
    char length;

    while (1) {
        slave.sendData(freq, addr, data, length);
    }
}
*/