// here i found some info regarding debug print using macro / and compiler switches
// http://forum.arduino.cc/index.php?topic=256308.0
// now i combine it with a toggle menu variable

// KLL 17.09.2014
//Sketch uses 6,374 bytes (22%) of program storage space. Maximum is 28,672 bytes.
//Global variables use 206 bytes (8%) of dynamic memory, leaving 2,354 bytes for local variables. Maximum is 2,560 bytes.
// shows:
//HALLO WORLD setup
//HALLO WORLD loop, type d[ENTER] to switch OFF 
//HALLO WORLD loop, type d[ENTER] to switch OFF ....
// until you send "d"[ENTER]
//#define DEBUG   // if compiler switch OFF see
//Sketch uses 6,182 bytes (21%) of program storage space. Maximum is 28,672 bytes.
//Global variables use 206 bytes (8%) of dynamic memory, leaving 2,354 bytes for local variables. Maximum is 2,560 bytes.


#define DEBUG

#ifdef DEBUG
#define db(t,x)       if(t) { Serial.print(x);  }
#define dbln(t,x)     if(t) { Serial.println(x); }
#else
#define db(t,x)       // define empty, so macro does nothing
#define dbln(t,x)
#endif 

boolean debugp = true;                             // variables dump to screen for diag
const long ser0bd = 115200;                        // 300, 1200 good, 2400, 9600 good, 14400, 19200 good, 28800, 38400 good, 57600 setpoint not good, 115200 good
//String inputstring = "";                           // a string to hold incoming data from the PC
int serloop = 0, serloopend = 5001;                // only after serloopend cycles check for USB income, because its slow
char inChar;                                       // operator input for menu operation
const char mline[]="_______________________________";

//___________________________________________________________________________________
void serial_setup() {

     Serial.begin(ser0bd);                                                     //set baud rate for the hardware serial port_0
#if defined(__PIC32MX__)

#else
     while (!Serial) {
                      ; // wait for serial port to connect. Needed for Leonardo only // not work?
                     }    
//     inputstring.reserve(20);                                                  //set aside some bytes for receiving data from the PC but seems to work also for longer strings??
#endif

}

//___________________________________________________________________________________
void one_char_operator_input_NOWAIT() {

      serloop = serloop + 1;                                                   // for check on USB 
      if (serloop == serloopend)       {
        serloop = 0;                                                           //reset and check ( after serloopend cycles )
                                                                               // by sending one byte from PC Terminal select job from menu
	if (Serial.available() > 0) {                                          // USB terminal interrupt NO WAIT and only check SERLOOPEND loops
		                                                               // read the first incoming byte:
             inChar = (char)Serial.read();                                     // take a byte
             while (Serial.available() > 0) { Serial.read(); }                 // clean the rest
                                    }                                          // end avail
                                     }                                         // after xxx loops check on serial available
                                      }                                        // end 
                                      
//___________________________________________________________________________________
void operator_HMI() {
      one_char_operator_input_NOWAIT();
            switch (inChar) {
#ifdef DEBUG
              case 'd': //a   menu entry 
                  //Serial.write(inByte);
                  debugp = !debugp;                          //toggle debug
              break;
#endif
              case ' ': //[space]
#ifdef DEBUG
                  Serial.println(F("  d: diag toggle"));
#endif
                  // here more menu ...
                  Serial.println(mline);    
                  Serial.print  (F("select: "));
              break;

            } // switch
    inChar = 0;    
                     }
                     
                     
//___________________________________________________________________________________
void setup() {
    serial_setup();
    dbln(debugp,F("HALLO WORLD setup"));
}

//___________________________________________________________________________________
void loop() {
    operator_HMI();
    dbln(debugp,F("HALLO WORLD loop, type d[ENTER] to switch OFF "));
  
}