#define LED PORTA.RA5
#define BTN PORTB.RB5
#define DIR PORTD.RD4

/*
Variaveis referente ao tratamento do protocolo
*/
#define SLAVE_ADRESS 1
char buffer[20];



/*
Function codes
*/
const char READ_COIL = 0x01;
const char WRITE_COIL = 0x05;

const char READ_INPUT_REGISTER = 0x03;

unsigned int read_temperature();
void crc_calc_and_send(char dataLenght);
void crc_calc(char dataLenght);
void send_buffer(char dataLenght);
void decode_packet();

unsigned int temp = 0;
bit led_status;

//DHT11 DEFINITONS
sbit DHT11_Pin at PORTB.B0;
sbit DHT11_DIR at TRISB.B0;
extern unsigned int DHT11_TMP;
extern unsigned int DHT11_HUM;
extern char DHT11_CHKSM;
//END OF DHT11 DEFINITONS

void main() {

     int timeout = 0;
     char packet_index = 0;


     TRISA = 0b11011111;
     TRISB = 0xFF;
     TRISD = 0;

     LED = 0;
     led_status = 0;

     DIR = 0; //listening for bus data

     ADC_Init();       /* Initialize the ADC module */
     DHT11_init();


     UART1_init(9600);
     Soft_UART_Init(&PORTB, 5, 4, 9600, 0); // debug stuff , rx pin RB5 and tx pin RB4

     while(1){

       timeout++;
       delay_us(1);

       if(timeout == 3640){ //timeout if no data is received
         timeout = 0;
         packet_index = 0;
       }

       if(!UART1_data_ready()) // don't proceed if UART is not ready
         continue;

       buffer[packet_index] = UART1_read(); // read packet
     //  Soft_UART_Write( buffer[packet_index]); //debug stuff

       packet_index++;
       timeout = 0;

       if(packet_index < 8) // continue reading packet
         continue;



       // packet end, start decoding

       packet_index = 0;   //reset index

       if(buffer[0] != SLAVE_ADRESS) // don't proceed if slave id doesn't match
         continue;

       decode_packet();
     }

}

void decode_packet(){
   char function_code = buffer[1];

   if(function_code == READ_COIL){
       if(buffer[2] == 0x00 && buffer[3] == 0x02){ //check register number
                    buffer[2] = 0x01;   //1 byte count
                  if(BTN)
                    buffer[3] = 0x00; // input state
                  else
                    buffer[3] = 0x01; // input state

                    crc_calc_and_send(4);
       }
   }


   if(function_code == WRITE_COIL){
      if(buffer[2] == 0x30 && buffer[3] == 0x20){ //check register number
             if(buffer[4] == 0xFF){
               LED = 1;
               led_status = 1;
             }

             if(buffer[4] == 0x00){
               LED = 0;
               led_status = 0;
             }

             crc_calc_and_send(6);
      }
   }

   if(function_code == READ_INPUT_REGISTER){
       if(buffer[4] == 0x00 && buffer[5] == 0x01){  //check size of data

         if(buffer[2] == 0x00 && buffer[3] == 0x01){ //check register number (potenciometer)

             buffer[2] = 0x00;   //2 byte count
             buffer[3] = 0x02;   //2 byte count


             buffer[4] = 0;
             buffer[5] = ADC_Read(0) >> 2; // convert 10 bits adc value to 8 bits

             crc_calc_and_send(6);
         }

         if(buffer[2] == 0x00 && buffer[3] == 0x02){ //check register number (dht11 temp)

             buffer[2] = 0x00;   //2 byte count
             buffer[3] = 0x02;   //2 byte count


             Dht11_Start();
             DHT11_Read();

             if(DHT11_CHKSM==((DHT11_TMP>>8)+(DHT11_HUM>>8)+(DHT11_TMP&0xff)+(DHT11_HUM&0xff))){

              buffer[4] = 0;
              buffer[5] = DHT11_TMP>>8; // convert dht11 temp value to 8 bits
            }

             crc_calc_and_send(6);
         }

         if(buffer[2] == 0x00 && buffer[3] == 0x03){ //check register number (dht11 temp)

             buffer[2] = 0x00;   //2 byte count
             buffer[3] = 0x02;   //2 byte count


             Dht11_Start();
             DHT11_Read();

             if(DHT11_CHKSM==((DHT11_TMP>>8)+(DHT11_HUM>>8)+(DHT11_TMP&0xff)+(DHT11_HUM&0xff))){

              buffer[4] = 0;
              buffer[5] = DHT11_HUM>>8; // convert dht11 temp value to 8 bits
            }

             crc_calc_and_send(6);
         }

         if(buffer[2] == 0x00 && buffer[3] == 0x04){ //check register number (ds18b20 temp)

             buffer[2] = 0x00;   //2 byte count
             buffer[3] = 0x02;   //2 byte count


             Ow_Reset(&PORTC, 5);                         // Onewire reset signal
             Ow_Write(&PORTC, 5, 0xCC);                   // Issue command SKIP_ROM
             Ow_Write(&PORTC, 5, 0x44);                   // Issue command CONVERT_T
             Delay_us(120);

             Ow_Reset(&PORTC, 5);
             Ow_Write(&PORTC, 5, 0xCC);                   // Issue command SKIP_ROM
             Ow_Write(&PORTC, 5, 0xBE);                   // Issue command READ_SCRATCHPAD

             buffer[5] = Ow_Read(&PORTC, 5);  // Write MSB
             buffer[4] = Ow_Read(&PORTC, 5);  // Write LSB

             crc_calc_and_send(6);
         }
       }
   }

}

void crc_calc_and_send(char data_lenght){
  crc_calc(data_lenght);
  send_buffer(data_lenght + 2);
}

void crc_calc(char data_lenght){
  unsigned int checksum = 0xFFFF;
  char j;
  char i;

  unsigned char lowCRC;
  unsigned char highCRC;

  for(j = 0; j < data_lenght; j++){
    checksum ^= (unsigned int)buffer[j];
    for(i = 8;i > 0; i--){
      if((checksum) & 0x0001)
        checksum = (checksum >> 1)^0xA001;
      else
        checksum >>=1;
    }
  }

  highCRC = checksum >> 8;
  lowCRC = checksum;
  buffer[data_lenght] = lowCRC;
  buffer[data_lenght + 1] = highCRC;
}

void send_buffer(char data_lenght){
     char i = 0;

     DIR = 1;
     delay_ms(5);

     for(i = 0; i < data_lenght; i++){
       UART1_write(buffer[i]);
     }

     delay_ms(5);
     DIR = 0;
}