/**
 *  Modbus master example 2:
 *  The purpose of this example is to query several sets of data
 *  from an external Modbus slave device.
 *  The link media can be USB or RS232.
 *
 *  Recommended Modbus slave:
 *  diagslave http://www.modbusdriver.com/diagslave.html
 *
 *  In a Linux box, run
 *  "./diagslave /dev/ttyUSB0 -b 19200 -d 8 -s 1 -p none -m rtu -a 1"
 *   This is:
 *    serial port /dev/ttyUSB0 at 19200 baud 8N1
 *    RTU mode and address @1
 */


#include <ModbusRtu.h>
#include <SoftwareSerial.h>
#define ID   0
//#define Led 3


uint16_t au16data[32]; //!< data array for modbus network sharing


uint8_t u8state; //!< machine state
uint8_t u8query; //!< pointer to message query




/**
 *  Modbus object declaration
 *  u8id : node id = 0 for master, = 1..247 for slave
 *  u8serno : serial port (use 0 for Serial)
 *  u8txenpin : 0 for RS-232 and USB-FTDI
 *               or any pin number > 1 for RS-485
 */
Modbus master(0,0,2); // this is master and RS-232 or USB-FTDI


/**
 * This is an structe which contains a query to an slave device
 */
modbus_t telegram[2];


unsigned long u32wait;


SoftwareSerial mySerial(0, 1);


void setup() {


ioset_up();
  // telegram 0: write single coil
  telegram[0].u8id = 1; // slave address
  telegram[0].u8fct = 5; // function code (this one is single coil)
  telegram[0].u16RegAdd = 0; // start address in slave
  telegram[0].u16CoilsNo = 2; // number of elements (coils or registers) to read
  telegram[0].au16reg = au16data[0]; // pointer to a memory array in the Arduino

  //telegram 1: write a single register
  telegram[1].u8id = 1; // slave address
  telegram[1].u8fct = 6; // function code (this one is write a single register)
  telegram[1].u16RegAdd = 1; // start address in slave
  telegram[1].u16CoilsNo = 4; // number of elements (coils or registers) to read
  telegram[1].au16reg = au16data[0]; // pointer to a memory array in the Arduino

  // telegram 2: write single coil
  telegram[2].u8id = 1; // slave address
  telegram[2].u8fct = 5; // function code (this one is single coil)
  telegram[2].u16RegAdd = 1; // start address in slave
  telegram[2].u16CoilsNo = 2; // number of elements (coils or registers) to read
  telegram[2].au16reg = au16data[0]; // pointer to a memory array in the Arduino

  Serial.begin( 9600);
  master.begin( 9600 ); // baud-rate at 9600
  master.begin( &mySerial, 9600 );
  master.setTimeOut( 3000 ); // if there is no answer in 3000 ms, roll over
  u32wait = millis() + 1000;
  u8state = u8query = 0;


  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);


}
void loop() {
  io_poll();


  switch( u8state ) {
  case 0:
    if (millis() > u32wait) u8state++; // wait state
    break;
  case 1:
    master.query( telegram[u8query] ); // send query (only once)
    u8state++;
  u8query++;
  if (u8query > 2) u8query = 0;
    break;
  case 2:
    master.poll(); // check incoming messages
    if (master.getState() == COM_IDLE) {
      u8state = 0;
      u32wait = millis() + 1000;

   Serial.print(au16data[0]);


    }
    break;


  // set digital outputs -> au16data[0]
  digitalWrite( 6, bitRead( au16data[0], 0 ));
  digitalWrite( 7, bitRead( au16data[0], 1 ));
  digitalWrite( 8, bitRead( au16data[0], 2 ));
  digitalWrite( 9, bitRead( au16data[0], 3 ));

  }
  }