/*
Example of processing incoming serial data without blocking.

Author: Nick Gammon
Date:   13 November 2011

Released for public use.
*/

// how much serial data we expect before a newline
const unsigned int MAX_INPUT = 50;

void setup ()
{
  Serial.begin(9600);
} // end of setup

// here to process incoming serial data after a terminator received
void process_data (char * data)
  {
  // for now just display it
  Serial.println (data);
  }  // end of process_data
  

void loop()
{
static char input_line [MAX_INPUT];
static unsigned int input_pos = 0;

  if (Serial.available () > 0) 
    {
    char inByte = Serial.read ();

    switch (inByte)
      {

      case '\n':   // end of text
        input_line [input_pos] = 0;  // terminating null byte
        
        // terminator reached! process input_line here ...
        process_data (input_line);
        
        // reset buffer for next time
        input_pos = 0;  
        break;
  
      case '\r':   // discard carriage return
        break;
  
      default:
        // keep adding if not full ... allow for terminating null byte
        if (input_pos < (MAX_INPUT - 1))
          input_line [input_pos++] = inByte;
        break;

      }  // end of switch

  }  // end of incoming data

  // do other stuff here like testing digital input (button presses) ...

}  // end of loop

R4500S80G3

// Example state machine reading serial input
// Author: Nick Gammon
// Date: 17 December 2011

// the possible states of the state-machine
typedef enum {  NONE, GOT_R, GOT_S, GOT_G } states;

// current state-machine state
states state = NONE;
// current partial number
unsigned int currentValue;

void setup ()
{
  Serial.begin (115200);
  state = NONE;
}  // end of setup

void processRPM (const unsigned int value)
{
  // do something with RPM 
  Serial.print ("RPM = ");
  Serial.println (value);
} // end of processRPM

void processSpeed (const unsigned int value)
{
  // do something with speed 
  Serial.print ("Speed = ");
  Serial.println (value);
} // end of processSpeed

void processGear (const unsigned int value)
{
  // do something with gear 
  Serial.print ("Gear = ");
  Serial.println (value);  
} // end of processGear

void handlePreviousState ()
{
  switch (state)
  {
  case GOT_R:
    processRPM (currentValue);
    break;
  case GOT_S:
    processSpeed (currentValue);
    break;
  case GOT_G:
    processGear (currentValue);
    break;
  }  // end of switch  

  currentValue = 0; 
}  // end of handlePreviousState

void processIncomingByte (const byte c)
{
  if (isdigit (c))
  {
    currentValue *= 10;
    currentValue += c - '0';
  }  // end of digit
  else 
  {

    // The end of the number signals a state change
    handlePreviousState ();

    // set the new state, if we recognize it
    switch (c)
    {
    case 'R':
      state = GOT_R;
      break;
    case 'S':
      state = GOT_S;
      break;
    case 'G':
      state = GOT_G;
      break;
    default:
      state = NONE;
      break;
    }  // end of switch on incoming byte
  } // end of not digit  
  
} // end of processIncomingByte

void loop ()
{
  if (Serial.available ())
    processIncomingByte (Serial.read ());

  // do other stuff in loop as required
  
}  // end of loop

  byte a, b, c, d, e;
  if (Serial.available () > 0)
    {
    a = Serial.read ();  
    b = Serial.read ();  
    c = Serial.read ();  
    d = Serial.read ();  
    e = Serial.read ();  
    }  // end of if serial data available

const byte LED = 13;

void flash ()
  {
  digitalWrite (LED, HIGH);
  digitalWrite (LED, LOW);
  }  // end of flash

void setup ()
 {
 pinMode (LED, OUTPUT);
 Serial.begin (115200);
 }  // end of setup
 
void loop ()
  {
  byte a, b, c, d, e;
  if (Serial.available () > 0)
    {
    flash ();
    a = Serial.read ();  
    flash ();
    b = Serial.read ();  
    flash ();
    c = Serial.read ();  
    flash ();
    d = Serial.read ();  
    flash ();
    e = Serial.read ();  
    flash ();  
    
    exit (0);  // stop program to save confusion
    }  // end of if serial data available
  } // end of loop

// Example of sending numbers by Serial
// Author: Nick Gammon
// Date: 31 March 2012

const char startOfNumberDelimiter = '<';
const char endOfNumberDelimiter   = '>';

void setup ()
  { 
  srand (42);
  Serial.begin (115200);
  } // end of setup
  
void loop ()
  {
  Serial.println ("Starting ...");
  for (int i = 0; i < 10; i++)
    {
    Serial.print (startOfNumberDelimiter);    
    Serial.print (rand ());    // send the number
    Serial.print (endOfNumberDelimiter);  
    Serial.println ();
    }  // end of for

  delay (5000);
  }  // end of loop

Starting ...
<17766>
<11151>
<23481>
<32503>
<7018>
<25817>
<28529>
<9160>
<16666>
<13513>

// Example of receiving numbers by Serial
// Author: Nick Gammon
// Date: 31 March 2012

const char startOfNumberDelimiter = '<';
const char endOfNumberDelimiter   = '>';

void setup ()
  { 
  Serial.begin (115200);
  Serial.println ("Starting ...");
  } // end of setup
  
void processNumber (const long n)
  {
  Serial.println (n);
  }  // end of processNumber
  
void processInput ()
  {
  static long receivedNumber = 0;
  static boolean negative = false;
  
  byte c = Serial.read ();
  
  switch (c)
    {
      
    case endOfNumberDelimiter:  
      if (negative) 
        processNumber (- receivedNumber); 
      else
        processNumber (receivedNumber); 

    // fall through to start a new number
    case startOfNumberDelimiter: 
      receivedNumber = 0; 
      negative = false;
      break;
      
    case '0' ... '9': 
      receivedNumber *= 10;
      receivedNumber += c - '0';
      break;
      
    case '-':
      negative = true;
      break;
      
    } // end of switch  
  }  // end of processInput
  
void loop ()
  {
  
  if (Serial.available ())
    processInput ();
    
  // do other stuff here
  } // end of loop

Starting ...
17766
11151
23481
32503
7018
25817
28529
9160
16666
13513