Getting correct information to the slave and some coding questions

Using Arduino Programming Questions
1

the char "H" would represent 1 byte
and the chars 'HL' would represent 2 bytes correct?

When i Write that on the Wire.write

would i phrase like

Wire.beginTransmission(5);
Wire.write ('HL');
Wire.endTransmission();

or

Wire.beginTransmission(5);
Wire.write ('H');
Wire.write ('L');
Wire.endTransmission();

or would these both do the same thing

also is there a tut on when to be using " " or ' '

from what i could understand while reading.. 'H' is actually telling it to send ASCII-encoded decimal of 72

if i wanted to send the dec value using the ASCII-encoded decimal way would i write it this way
Wire.write (", dec:72");

2

the char "H" would represent 1 byte
and the chars 'HL' would represent 2 bytes correct?

Where would this be ?

Wire.write() can take one of different types of parameter as follows

Wire.write(value)
Wire.write(string)
Wire.write(data, length)

value: a value to send as a single byte

string: a string to send as a series of bytes

data: an array of data to send as bytes

length: the number of bytes to transmit

Where do H and HL fit into this ?

Please post the code that you are having problems with.

3

Here are the sketches for master and slave

instead of attempting at 2 bytes im going for four bytes as a fix on this at 4 bytes should solve most of my issues

Problem im incurring is on button press of button2 the correct information Wire.write ('B2BH'); or the depress of that button is not getting sent to the slave in a way the slave can understand it.
im trying to figure out how to get the correct 4 bytes recognized by the slave.

Sketch Master

/* Master Arduino code (Leonardo)

  uses 2 Arduino's
  1 set as master the other set as slave more less to double I/O pins
  Master collects digital input button toggles and sends them to slave
  via Wire.write using I2C method
  Slave acts as the output indicator controlling multiple LEDS that indicate
  which buttons on the master are toggled on or off
  Also in addition the Master functions as a Keyboard relaying a keystroke
  When the switches are togggled from either position.
*/


#include <Wire.h>

const int button1Pin = 4;       // pin 4 is not the I2C bus for the Leonardo
const int button2Pin = 5;


const int JoyDown1ThrottlePin = 8;
const int JoyUp1ThrottlePin = 9;
int previousJoyUp1ThrottleState = HIGH;
int previousJoyDown1ThrottleState = HIGH;

int previousButton1State = HIGH;   // for checking the state of button1
int previousButton2State = HIGH;   // for checking the state of button2

void setup() {
  Serial.begin (9600);
  
  //while(!Serial);       // wait for the serial monitor for the Leonardo
  
  Serial.println(F("Master started"));
  
  Keyboard.begin ();      // only available in the Leonardo
  pinMode (button1Pin, INPUT_PULLUP);
  pinMode (button2Pin, INPUT_PULLUP);
  
  
  pinMode (JoyUp1ThrottlePin, INPUT_PULLUP);
  pinMode (JoyDown1ThrottlePin, INPUT_PULLUP);
  Wire.begin();

  // put your setup code here, to run once:

}

void loop() {

  
  // Start of Joy1UpThrottle

  int JoyUp1State = digitalRead(JoyUp1ThrottlePin);
  
  // check if the button state has changed.
  if (JoyUp1State != previousJoyUp1ThrottleState) {
    if( JoyUp1State == HIGH) {
      Serial.println ("JoyUpThrottleAxisCentered");

      //Wire.beginTransmission(5);  //REMoved not controlling a LED here
      //Wire.write ('S');           //REMoved not controlling a LED here
      //Wire.endTransmission();     //REMoved not controlling a LED here

      //Keyboard.release (KEY_LEFT_SHIFT);
    }
    else {
      Serial.println ("Joy1UpThrottleUp");

      //Wire.beginTransmission(5);  //REMoved not controlling a LED here
      //Wire.write ('W');           //REMoved not controlling a LED here
      //Wire.endTransmission();     //REMoved not controlling a LED here

      //Keyboard.press (KEY_LEFT_SHIFT);
    }
    
    previousJoyUp1ThrottleState = JoyUp1State;
  }
  // End of JoyUp1Throttle
  
  
  // Start of Joy1DownThrottle

  int JoyDown1State = digitalRead(JoyDown1ThrottlePin);
  
  // check if the button state has changed.
  if (JoyDown1State != previousJoyDown1ThrottleState) {
    if( JoyDown1State == HIGH) {
      Serial.println ("Joy_Y_Axis_Centered");

      //Wire.beginTransmission(5);  //REMoved not controlling a LED here
      //Wire.write ('S');           //REMoved not controlling a LED here
      //Wire.endTransmission();     //REMoved not controlling a LED here

      //Keyboard.release (KEY_LEFT_CTRL);
    }
    else {
      Serial.println ("Joy_Y_Axis_+");

      //Wire.beginTransmission(5); //REMoved not controlling a LED here
      //Wire.write ('W');          //REMoved not controlling a LED here
      //Wire.endTransmission();    //REMoved not controlling a LED here

      //Keyboard.press (KEY_LEFT_CTRL);
    }
    
    previousJoyDown1ThrottleState = JoyDown1State;
  }
  // End of JoyDown1Throttle
  
  
  // Start of Button1

  int button1State = digitalRead(button1Pin);
  
  // check if the button state has changed.
  if (button1State != previousButton1State) {
    if( button1State == HIGH) {
      Serial.println ("Button1Released"); 

      Wire.beginTransmission(5); // Assign a destination
      Wire.write ('L');          // Queing into memory to send 1 byte 
      Wire.endTransmission();    //Transmit the byte

      //Keyboard.print ('Later_Defined');
    }
    else {
      Serial.println ("Button1Pressed");

      Wire.beginTransmission(5); // Assign a destination
      Wire.write ('H');          // Queing into memory to send 1 byte 
      Wire.endTransmission();    //Transmit the byte

      //Keyboard.print ('Later_Defined');
    }
    
    previousButton1State = button1State;
  }
  // End of Button1
  
  delay(50);      // slow down loop



// Start of Button2

  int button2State = digitalRead(button2Pin);
  
  // check if the button state has changed.
  if (button2State != previousButton2State) {
    if( button2State == HIGH) {
      Serial.println ("Button2Released");
   

      Wire.beginTransmission(5);     // Assign a destination
      Wire.write ('B2BL');             // Attempt at Queing 4 bytes 
      Wire.endTransmission();        //Transmit the bytes
      
      //Keyboard.print ('Later_Defined');
    }
    else {
      Serial.println ("Button2Pressed");

      Wire.beginTransmission(5);    // Assign a destination
      Wire.write ('B2BH');            // Attempt at Queing 4 bytes
      Wire.endTransmission();       //Transmit the bytes 

      //Keyboard.print ('Later_Defined');
    }
    
    previousButton2State = button2State;
  }
  // End of Button2


}

Sketch Slave

/* SLAVE Arduino CODE (MEGA2560)

uses 2 Arduino's
  1 set as master the other set as slave more less to double I/O pins
  Master collects digital input button toggles and sends them to slave
  via Wire.write using I2C method
  Slave acts as the output indicator controlling multiple LEDS that indicate
  which buttons on the master are toggled on or off
  Also in addition the Master functions as a Keyboard relaying a keystroke
  When the switches are togggled from either position.
*/
#include <Wire.h>

const int button1LedGreen = 13;
const int button1LedRed = 12;
const int button2LedGreen = 11;
const int button2LedRed = 10;

void setup() 
{
  Serial.begin(9600);
  //Serial.println(F("Slave started"));
  Serial.println ("Slave Started");
  pinMode(button1LedGreen, OUTPUT);  // output for LED1 from toggle Button 1 ON
  pinMode(button1LedRed, OUTPUT);  // output for LED2 from toggle Button 1 OFF
  pinMode(button2LedGreen, OUTPUT);  // output for LED2 from toggle Button 2 ON
  pinMode(button2LedRed, OUTPUT);  // output for LED2 from toggle Button 2 OFF
  digitalWrite (button1LedGreen, LOW);
  digitalWrite (button1LedRed, LOW);
  digitalWrite (button2LedGreen, LOW);
  digitalWrite (button1LedRed, LOW);
  
  Wire.begin(5);
  Wire.onReceive(receiveEvent);
}

void loop() 
{
}

void receiveEvent(int howMany)
{
  
  // start of receive one byte
  // we are expecting just a single byte
  if (howMany == 1)

  {
    char c = Wire.read();
    
    // Start of LED1 for Button1
    if (c == 'H')
    {
      digitalWrite(button1LedGreen, HIGH);
      digitalWrite(button1LedRed, LOW);
      Serial.print (c);
    }
    else if (c == 'L')
    {
      digitalWrite(button1LedRed, HIGH);
      digitalWrite(button1LedGreen, LOW);
      
      // End of LED1 for Button1
     
    }
   Serial.println (c);
    
    //End of receive 1 byte
    
  }


  // My attempt to receive 4 bytes
 if (howMany == 4)

  {
    char d = Wire.read();
   
    Serial.println (d);
    // Start of LED2 for Button2
    if (d == 'B2BH')
    {
      digitalWrite(button2LedGreen, HIGH);
      digitalWrite(button2LedRed, LOW);
    }
    else if (d == 'B2BL')
    {
      digitalWrite(button2LedRed, HIGH);
      digitalWrite(button2LedGreen, LOW);
      
      // End of LED1 for Button1
     
    }
   Serial.println (d);
    
    //End of Attempt at Four bytes received
}
}