// modbus slave PA 6cm control rgk 2018
// bedoeld voor een arduino nano board
#include <SimpleModbusSlave.h>
#include <Wire.h>
/* 
   SimpleModbusSlaveV10 supports function 3, 6 & 16.
   The modbus_update() method updates the holdingRegs register array and checks
   communication.

   REG_1 = control register (read)
   REG_2 = status register (write)
*/

#define MCP 0x4d      //I2c adres van de MCP9800 temperatuursensor
#define LED_ERR   11  // error led datacommunicatie
#define SLAVE_ID  3   // modbus slave adres
#define TX_RX     2   // RS485 Rx/Tx omschakel lijn

//control register low-byte 
#define PA_ON     0
#define TX_COAX   1
#define TX_MUTE   2

//status register low-byte (high byte is temperatuur uitlezing)
#define PA_STATUS 0

// digital pins 
#define POWER_ON  3
#define COAX      4
#define MUTE      5
#define STATUS    6


// Using the enum instruction allows for an easy method for adding and 
// removing registers. Doing it this way saves you #defining the size 
// of your slaves register array each time you want to add more registers
// and at a glimpse informs you of your slaves register layout.

//////////////// registers of your slave ///////////////////
enum 
{     
  // just add or remove registers and your good to go...
  // The first register starts at address 0
  REG_1,
  REG_2,        
  HOLDING_REGS_SIZE // leave this one
  // total number of registers for function 3 and 16 share the same register array
  // i.e. the same address space
};

unsigned int holdingRegs[HOLDING_REGS_SIZE]; // function 3 and 16 register array

////////////////////////////////////////////////////////////

void setup()
{
  Wire.begin(); // start de i2c service
  modbus_configure(&Serial, 38400, SERIAL_8N2, SLAVE_ID, TX_RX, HOLDING_REGS_SIZE, holdingRegs);
  pinMode(TX_RX,OUTPUT);
  pinMode(LED_ERR, OUTPUT);
  pinMode(POWER_ON,OUTPUT);
  pinMode(COAX,OUTPUT);
  pinMode(MUTE,OUTPUT);
  pinMode(STATUS,INPUT_PULLUP);
  
  

}

void loop()
{
  static byte CONTROL=0;
  static byte CONTROL_OLD=0;
  static int error;
  static unsigned int data;
  static long tijd;
  static long tijd_oud = 0;
  static int interval = 100; // delay time tussen coax om en TX-ON
  static bool send_enable;
  static char TEMP;
  tijd = millis();     
  error = modbus_update();
  TEMP = get_temp();
  CONTROL = lowByte(holdingRegs[REG_1]);
  if(CONTROL != CONTROL_OLD){    
    digitalWrite(POWER_ON,bitRead(CONTROL,PA_ON));
    digitalWrite(COAX,bitRead(CONTROL,TX_COAX));
    if(bitRead(CONTROL,TX_MUTE) == 1){
      send_enable = 1;
      }
    else{
      send_enable = 0;
      digitalWrite(MUTE,0);
    }
    tijd_oud = tijd;  
    CONTROL_OLD=CONTROL;
  }
  data=0;
  data |= digitalRead(STATUS);
  data |= TEMP*256;
  holdingRegs[REG_2] = data;
  
  if(error>10)digitalWrite(LED_ERR,HIGH);
  else digitalWrite(LED_ERR,LOW);

  if(tijd-tijd_oud > interval & send_enable==1){
  digitalWrite(MUTE,1);
  tijd_oud=tijd;
  }
  if(TEMP>45){
    send_enable = 0;
    digitalWrite(MUTE,0);
  }
}

char get_temp(){
  Wire.beginTransmission(MCP);
  Wire.write(00);
  Wire.requestFrom(MCP,2);
  char hi = Wire.read();
  char lo = Wire.read();//discard
  if(hi>127)hi-=256;
//  hi=0x16;//test temp
  return hi;  
}