Master-SlaveCommunication

// --------------------------- slave -------------------------------------------
#include <Wire.h>

int led=13;

char cmd[100];
void setup()
{
  Wire.begin(1);
  Wire.onReceive(recEvent);
  pinMode(led, OUTPUT);
  digitalWrite(led, LOW);
  digitalWrite(10, HIGH);
}

void loop()
{
  delay(100);
}

void proc()
{
  char * a=(char *)malloc(15);
  char * b=(char *)malloc(15);

  a=strtok(cmd, " ");
  b=strtok('\0', " ");

  if(strcmp(a, "speed")==0)
  {
    analogWrite(13, 150);
  }
  if(strcmp(a, "steps")==0)
  {
    analogWrite(13, 0);
  }
}


void recEvent(int n)
{
  cmd[0]='\0';
  int i=0;
  while(Wire.available())
  {
    cmd[i++]=Wire.read();
    cmd[i]='\0';
  }
  proc();
}

// ------------------------------------------- master --------------------------------------------
#include <Wire.h>

void setup()
{
  Wire.begin();
  Serial.begin(19200);
}
char cmd[100];

void Read()
{
  cmd[0]='\0';
  int i=0;
  char character;

  while(Serial.available()) {
      character = Serial.read();
      cmd[i++]=character;
      cmd[i]='\0';
      delay(1);
  }

}

void loop()
{
  Read();
  if(cmd[0]!='\0')
  {
    Wire.beginTransmission(1);
    Wire.write(cmd);
    Wire.endTransmission();
    delay(500);

  }


}