//*****************************************************
//RFM12B OKK sections taken from the original Jeenode OKK Raw example
//Tested with Arduino 0021
// polling RFM12B to decode FSK iT+ with a Jeenode from Jeelabs.
// device  : iT+ TX29IT 04/2010 v36 D1 LA Crosse Technology (c)
// info    : http://forum.jeelabs.net/node/110
//           http://fredboboss.free.fr/tx29/tx29_sw.php
//           http://www.f6fbb.org/domo/sensors/
//           benedikt.k http://www.mikrocontroller.net/topic/67273
//           rinie,marf,joop 1 nov 2011
// *****************************************************
// * Resouces used:- 
// *http://www.susa.net/wordpress/2012/08/raspberry-pi-reading-wh1081-weather-sensors-using-an-rfm01-and-rfm12b/
// * jeenode_lacross_rx by Rufik
// *****************************************************
// 09/01/2013 V 0.01 Initial WH1080 fine offset Arduino decoder
//                   by Steve Pyle
//******************************************************
//************     To Do / Change log   ****************
//
//
// *****************************************************



#include <util/delay.h>
#include "Arduino.h"

#define clrb(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#define setb(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))

#define RF_PORT PORTB
#define RF_DDR DDRB
#define RF_PIN PINB

#define SDI 3 
#define SCK 5 
#define CS 2
#define SDO 4


#define CRC_POLY 0x31 // CRC-8 = 0x31 is for: x8 + x5 + x4 + 1
#define DEBUG 1 // set to 1 to see debug messages


int frame; 
int device_id;  
int temperature_raw; 
float temperature;  
int humidity; 
float wind_avg_ms; 
float wind_avg_mph; 
int wind_avg_raw; 
int wind_gust_raw; 
float wind_gust_ms; 
float wind_gust_mph; 
float rain; 
int rain_raw; 
int wind_direction;

char *direction_name[] = {"N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"};



//Receive message, data[] 
void receive(unsigned int *data)
{  unsigned char mesage[20];

   if (DEBUG) { Serial.println("Listening...."); }

  rf12_rxdata(mesage,20);

  if (DEBUG) {
    Serial.print("Received HEX raw data: ");
    for (int i=0; i<20; i++) { 
//     for(uint8_t i = 0; i<20; i++) 
      Serial.print(mesage[i], HEX);
      Serial.print(" ");
    }
    Serial.println();
  }
  
 //Write message into table
// for(uint8_t i = 0; i<20; i++)
  for (int i=0; i<20; i++) { //20
    data[i] = (unsigned int) mesage[i];
  }
}



// Calculate CRC
static uint8_t compute_crc(uint8_t b) {
  uint8_t do_xor;
  uint8_t reg;

  reg = 0;
  do_xor = (reg & 0x80);

  reg <<=1;
  reg |= b;

  if (do_xor) {
    reg ^= CRC_POLY;
  }

  return reg;
}




//check if CRC is OK
boolean is_crc_valid(unsigned int crcByte) {
  boolean result = false;
  
  uint8_t crc_computed = compute_crc((uint8_t) crcByte);
  if ((unsigned int) crc_computed == crcByte) {
    result = true;
    if (DEBUG) { Serial.print("CRC OK: "); Serial.println(crc_computed, HEX); }
  } else {
    if (DEBUG) {
      Serial.print("CRC Error... Calculated is "); Serial.print(crc_computed, HEX);
      Serial.print(" Received is "); Serial.println(crcByte, HEX);
    }

  }
  return result;
}




//Check if msg starts with A (WH1080)
boolean is_msg_valid(unsigned int msgFirstByte) {
  boolean result = false;

  unsigned int msgFlag = (msgFirstByte & 240) >> 4;
  if (msgFlag == 10) {
    result = true;
    if (DEBUG) { Serial.println("OK"); }
  } else {
    if (DEBUG) { Serial.print("Msg does not start with A, it's: "); Serial.println(msgFlag, HEX);}
  }
  return result;
}



void rf12_rxdata(unsigned char *data, unsigned char number)
{	uint8_t  i;
	rf12_xfer(0x82C8);			// receiver on
	rf12_xfer(0xCA81);			// set FIFO mode
	rf12_xfer(0xCA83);			// enable FIFO
	for (i=0; i<number; i++)
	{	rf12_ready();
		*data++=rf12_xfer(0xB000);
	}
	rf12_xfer(0x8208);			// Receiver off 
}

// ******** SPI + RFM 12B functies   ************************************************************************

unsigned short rf12_xfer(unsigned short value)
{	uint8_t i;

	clrb(RF_PORT, CS);
	for (i=0; i<16; i++)
	{	if (value&32768)
			setb(RF_PORT, SDI);
		else
			clrb(RF_PORT, SDI);
		value<<=1;
		if (RF_PIN&(1<<SDO))
			value|=1;
		setb(RF_PORT, SCK);
		asm("nop");
		asm("nop");
		clrb(RF_PORT, SCK);
	}
	setb(RF_PORT, CS);
	return value;
}


void rf12_ready(void)
{
clrb(RF_PORT, CS);
asm("nop");
asm("nop");
while (!(RF_PIN&(1<<SDO))); // wait until FIFO ready
setb(RF_PORT, CS);
}


static void rf12_la_init() 
{
RF_DDR=(1<<SDI)|(1<<SCK)|(1<<CS);
RF_PORT=(1<<CS);
for (uint8_t  i=0; i<10; i++) _delay_ms(10); // wait until POR done
rf12_xfer(0x80E8); // 80e8 CONFIGURATION EL,EF,868 band,12.5pF      // iT+ 915  80f8 
rf12_xfer(0xA67c); // a67c FREQUENCY SETTING 868.300                // a67c = 915.450 MHz
rf12_xfer(0xC613); // c613 DATA RATE c613  17.241 kbps
rf12_xfer(0xC26a); // c26a DATA FILTER COMMAND 
rf12_xfer(0xCA12); // ca12 FIFO AND RESET  8,SYNC,!ff,DR 
rf12_xfer(0xCEd4); // ced4 SYNCHRON PATTERN  0x2dd4 
rf12_xfer(0xC49f); // c49f AFC during VDI HIGH +15 -15 AFC_control_commAND
rf12_xfer(0x94a0); // 94a0 RECEIVER CONTROL VDI Medium 134khz LNA max DRRSI 103 dbm  
rf12_xfer(0xCC77); // cc77 not in RFM01 
rf12_xfer(0x9872); // 9872 transmitter not checked
rf12_xfer(0xE000); // e000 NOT USE 
rf12_xfer(0xC800); // c800 NOT USE 
rf12_xfer(0xC040); // c040 1.66MHz,2.2V 
}


void setup () {
  Serial.begin(57600);
  if (DEBUG) {
    Serial.println("WH1080 Weather Station Wireless Receiver ");
  }
  rf12_la_init();
  if (DEBUG) {
    Serial.println("RF Module setup complete");
}
}


void loop ()
{
  unsigned int frame[20];
  //get message
  receive(frame);
  //check if valid for Fineoffset (WH1080)
  if (is_msg_valid(frame[0])) {
   // check CRC
    if (is_crc_valid(frame[9]))
 
    {
	device_id = ((frame[0] << 4) | (frame[1] >> 4));
        temperature_raw = ((frame[1] & 0x0f) << 8) | (frame[2]);
	temperature = (float)temperature_raw / 10 ;
	humidity = frame[3];
	
	wind_avg_raw = frame[4];
	wind_avg_ms = ((float)wind_avg_raw * 34.0) / 100;
	wind_avg_mph = wind_avg_ms * 2.23693629;

	wind_gust_raw = frame[5];
	wind_gust_ms = ((float)wind_gust_raw * 34.0) / 100;
	wind_gust_mph = wind_gust_ms * 2.23693629;
	
	rain_raw = ((frame[6] & 0x0f) << 8) | frame[7];
	
	rain = (float)rain_raw * 0.3;
	
	wind_direction = frame[8] & 0x0f;
	char *direction_str = direction_name[wind_direction];
	
        Serial.print("Id: ");
	Serial.println(device_id);
        Serial.print("Temperature: ");
        Serial.println(temperature);
	Serial.print("Humidity: ");
        Serial.println(humidity);
        Serial.print("Wind avg: ");
        Serial.print(wind_avg_ms);
        Serial.print("m/s or ");
        Serial.print(wind_avg_mph);
        Serial.println("mph");
        Serial.print("Wind Gust: ");
        Serial.print(wind_gust_ms);
        Serial.print("m/s or ");
        Serial.print(wind_gust_mph);
        Serial.println("mph");
        Serial.print("Wind Direction: ");
        Serial.println(direction_str);
	Serial.print("Total rain: ");
        Serial.print(rain);
        Serial.println("mm");
        Serial.flush();

      
   }
  }
}