 {
   // Process incoming serial data, and perform callbacks
   cmdMessenger.feedinSerialData();
-
-  // Toggle LED periodically. If the LED does not toggle every 2000 ms, 
-  // this means that cmdMessenger are taking a longer time than this  
-  if (hasExpired(previousToggleLed,2000)) // Toggle every 2 secs
-  {
-    toggleLed();  
-  } 
 }
-
-// Toggle led state 
-void toggleLed()
-{  
-  ledState = !ledState;
-  digitalWrite(kBlinkLed, ledState?HIGH:LOW);
-}  

// In order to receive, attach a callback function to these events
enum
{
  // Commands
  kAcknowledge         , // Command to acknowledge that cmd was received
  kError               , // Command to report errors
  kFloatAddition       , // Command to request add two floats
  kFloatAdditionResult , // Command to report addition result
};

// Commands we send from the PC and want to receive on the Arduino.
// We must define a callback function in our Arduino program for each entry in the list below.

void attachCommandCallbacks()
{
  // Attach callback methods
  cmdMessenger.attach(OnUnknownCommand);
  cmdMessenger.attach(kFloatAddition, OnFloatAddition);
}

// ------------------  C A L L B A C K S -----------------------

// Called when a received command has no attached function
void OnUnknownCommand()
{
  cmdMessenger.sendCmd(kError,"Command without attached callback");
}

// Callback function that responds that Arduino is ready (has booted up)
void OnArduinoReady()
{
  cmdMessenger.sendCmd(kAcknowledge,"Arduino ready");
}

// Callback function calculates the sum of the two received float values
void OnFloatAddition()
{
  // Retreive first parameter as float
  float a = cmdMessenger.readFloatArg();
  
  // Retreive second parameter as float
  float b = cmdMessenger.readFloatArg();
  
  // Send back the result of the addition
  //cmdMessenger.sendCmd(kFloatAdditionResult,a + b);
  cmdMessenger.sendCmdStart(kFloatAdditionResult);
  cmdMessenger.sendCmdArg(a+b);
  cmdMessenger.sendCmdArg(a-b);
  cmdMessenger.sendCmdEnd();
}

// ------------------ M A I N  ----------------------

// Setup function
void setup() 
{
  // Listen on serial connection for messages from the pc
  Serial.begin(115200); 

  // Adds newline to every command

  attachCommandCallbacks();

  // Send the status to the PC that says the Arduino has booted
  // Note that this is a good debug function: it will let you also know 
  // if your program had a bug and the arduino restarted  
  cmdMessenger.sendCmd(kStatus,"Arduino has started!");

  // set pin for blink LED
  pinMode(kBlinkLed, OUTPUT);
}

// Loop function
