File content as of revision 4:133b49d51b18:

#include "mbed.h"
#include "rtos.h"

void write_to_master(char);                    //function to write data to master
Thread * ptr_t_i2c;
I2CSlave slave(D14,D15);                       //configuring pins p27, p28 as I2Cslave
Serial pc (USBTX,USBRX);
InterruptIn interrupt(D9);

typedef struct
{
    char data;          // To avoid dynamic memory allocation
    int length;
}i2c_data;

Mail<i2c_data,16> i2c_data_receive;
Mail<i2c_data,16> i2c_data_send;

void FUNC_I2C_WRITE2CDMS(char *data_receive,char *data_send, int length=1)
{
       
    int slave_status = 1;
    while(slave_status)
    {                 
            slave.address(0x20);
            if(slave.receive()==1)
            {
                slave_status=slave.write(data_send,length);
               // printf("\n In the while loop\n");
                
                /*if(!slave_status)
                {
                        printf("slave wrote %c to master\n\r",*data);
              
                }*/
                
            }
            else
                if(slave.receive()==3 || slave.receive()==2)
                {
                     //i2c_data *i2c_data_r = i2c_data_receive.alloc();
                     slave_status=slave.read(data_receive,length);
                     /*if(!slave_status)
                     {
                         printf("1 read %c from master\n\r",*data);
                     }*/
                }
            //slave.stop();
    }
            printf("2 done");

}

void T_I2C_BAE(void const * args)
{
    char data_send,data_receive;
    data_send = 'a';
    while(1)
    {
        Thread::signal_wait(0x1);
        FUNC_I2C_WRITE2CDMS(&data_receive,&data_send);
        //printf("\n Data received from CDMS is %c\n",data_receive);
        i2c_data * i2c_data_r = i2c_data_receive.alloc();
        i2c_data_r->data = data_receive;
        i2c_data_r->length = 1;
        i2c_data_receive.put(i2c_data_r);
    }
}
        
void FUNC_INT()
{
  // char * data = new char;
   //*data = 'a';
   ptr_t_i2c->signal_set(0x1);
   //delete data;
}
   


void main()
{
    printf("\nStarted slave... waiting for master\n");
    ptr_t_i2c = new Thread(T_I2C_BAE);
    char data='a';
    interrupt.rise(&FUNC_INT);
    while(1)
    {
        //*(data_send)=pc.getc();
        
        //FUNC_I2C_WRITE2CDMS(&data,1);
        //printf("\n The data send or received by slave is %c\n",data);
        //(data)++;
        //wait(1);
         osEvent evt = i2c_data_receive.get();
         if (evt.status == osEventMail) 
         {
            i2c_data *i2c_data_r = (i2c_data*)evt.value.p;
            printf("\nData read from CDMS is %c\n",i2c_data_r->data);
            
            i2c_data_receive.free(i2c_data_r);
            //delete i2c_data_r;
        }
        
    }
}