File content as of revision 0:21ffb42911bd:

#include "mbed.h"

char* read_from_master();                    //function to write data to master
int write_to_master(char*,int);

I2CSlave slave(D14,D15);                       //configuring pins p27, p28 as I2Cslave
Serial pc (USBTX,USBRX);

bool read_loop  = true;
bool write_loop = true;
char *data_rec  = new char;
char *data_send = new char;
char *rec_data  = new char;
int  slave_status = 1;
int k;


int main(){
    
    slave.address(0x20);  
    while(1){  
        slave.stop();
        printf("11 press any character for slave to start \n\r");
        *data_send = pc.getc();
        
        printf("1 in main\n\r");
        k = write_to_master(data_send,1);
        printf("4 done transfer with return %d\n\r",k);
    }           
    
}    
        
    
char* read_from_master(){
    
    while(slave_status)
                slave_status=slave.read(data_rec,1);
                
    return(data_rec);
                
     
     //read_loop = true;
     //slave.stop();
     
}  
    
int write_to_master(char* send, int length){
    slave_status=1;
    while(slave_status){
                printf("2 wait for status\n\r");
                //if(slave.receive()==1)
                     {
                     slave_status=slave.write(send,length);
                }
    }                 
    printf("3 wrote %c to master\n\r",*data_send);

            //slave.stop();
    return(1);
}