#include <ModbusRtu.h>

uint16_t au16data[16]; //!< data array for modbus network sharing  Array
uint8_t u8state; //!< machine state
uint8_t u8query; //!< pointer to message query

Modbus master(0,0,2); // this is master and RS-232 or USB-FTDI  ///  7 = PIN ENEABLE rs485

modbus_t telegram[0];

unsigned long u32wait;

const int  switchOnePin = 3;    // digital in 2 (pin the switch one is attached to)
const int  switchTwoPin = 4;    // digital in 3 (pin the switch two is attached to)
const int  switchThreePin = 5;  // digital in 4 (pin the switch three is attached to)
const int  LED1 = 8;    // digital in 2 (pin the switch one is attached to)
const int  LED2 = 9;    // digital in 3 (pin the switch two is attached to)
const int  LED3 = 10;  // digital in 4 (pin the switch three is attached to)


int switchOneState = 0;         // current state of the switch
int lastSwitchOneState = 0;     // previous state of the switch

int switchTwoState = 0;
int lastSwitchTwoState = 0;

int switchThreeState = 0;
int lastSwitchThreeState = 0;


void setup() {

    master.setTimeOut( 5000 ); // if there is no answer in 5000 ms, roll over
    u32wait = millis() + 1000;
    u8state = u8query = 0;

    //initialize serial communication at 9600 bits per second:
    Serial.begin(9600);

    int switchOneState = 0;         // current state of the switch
    int lastSwitchOneState = 0;     // previous state of the switch switch pins as an input
    pinMode(switchOnePin, INPUT);
    pinMode(switchTwoPin, INPUT);
    pinMode(switchThreePin, INPUT);
    pinMode(LED1, OUTPUT);
    pinMode(LED2, OUTPUT);
    pinMode(LED3, OUTPUT);
}

void loop() {
      master.poll(); // check incoming messages
    if (master.getState() == COM_IDLE) {
       u32wait = millis() + 100;

    // read the switch input pins:
    switchOneState   = digitalRead(switchOnePin);
    switchTwoState   = digitalRead(switchTwoPin);
    switchThreeState = digitalRead(switchThreePin);

    // compare the switchState to its previous state
    if (switchOneState != lastSwitchOneState) {
        // if the state has changed, increment the counter
        if (switchOneState == HIGH) {
        // if the current state is HIGH then the button
        // went from off to on:
            //digitalWrite(LED1, HIGH);
            //Serial.println("Switch one is on");

   telegram[0].u8id = 1;                // slave address
   telegram[0].u8fct = 5;               // function code (write Single coil)
   telegram[0].u16RegAdd = 0;           // start address in slave -  direccion de Inicio 0
   telegram[0].u16CoilsNo = 2;          // number of elements (coils or registers) to read  0 - 16
   master.query( telegram[0] ); // send query (only once)
        } else {
            if (switchOneState == LOW)
            // if the current state is LOW then the button
            // went from on to off:
            //Serial.println("Switch one is off");
            digitalWrite(LED1, LOW);
        }
    }

    if (switchTwoState != lastSwitchTwoState) {
        if (switchTwoState == HIGH) {
            //Serial.println("Switch two is on");
            //digitalWrite(LED2, HIGH);
              // telegram 1: write a multiple  register = function 16
  telegram[1].u8id = 1;                 // slave address
  telegram[1].u8fct = 6;               // function code (write multiple registers 16 )
  telegram[1].u16RegAdd = 1;           // start address in slave  -  direccion de Inicio 10
  telegram[1].u16CoilsNo = 4;          // number of elements (coils or registers) to read
//   telegram[1].au16reg[0] = 0;
master.query( telegram[1] ); // send query (only once)
        } else {
            //Serial.println("Switch two is off");
            //digitalWrite(LED2, LOW);
        }
    }

    if (switchThreeState != lastSwitchThreeState) {
        if (switchThreeState == HIGH) {
            //Serial.println("Switch three is on");
            //digitalWrite(LED3, HIGH);
    telegram[2].u8id = 1; // slave address
    telegram[2].u8fct = 5; // function code (this one is registers read)
    telegram[2].u16RegAdd = 0; // start address in slave
    telegram[2].u16CoilsNo = 0; // number of elements (coils or registers) to read
//    telegram.au16reg = au16data; // pointer to a memory array in the Arduino
master.query( telegram[3] ); // send query (only once)
        } else {
            //Serial.println("Switch thre is off");
            //digitalWrite(LED3, LOW);
        }
    }

    // Delay a little bit to avoid bouncing
    delay(50);

    // save the current state as the last state,
    //for next time through the loop
    lastSwitchOneState   = switchOneState;
    lastSwitchTwoState   = switchTwoState;
    lastSwitchThreeState = switchThreeState;
    }
}