#include "Wire.h"

 int Address = 0x69; // device address of SPS30 (fixed).

 byte w1, w2,w3;
 byte ND[60];
 long tmp;
 float measure;
 
void setup() {
  //enabling VDD_SW power rail to give 5V source to the dolfin board
 pinMode(SW_VDD_EN, OUTPUT);
 digitalWrite(SW_VDD_EN,HIGH);
 //enabling 5V_sensor power rail to switch on the sensor
 pinMode(EXP_36, OUTPUT);
 digitalWrite(EXP_36,HIGH);
 //enabling 3V3_SW power rail to pull the I2C bus up via the 10K resistors
 pinMode(SW_3V3_EN, OUTPUT);
 digitalWrite(SW_3V3_EN,HIGH);
 //wait for the power sources to be turned on
 delay(1000);
 
  Wire1.begin(); // Initiate the Wire1 instance
  Serial.begin(115200);
  delay(100);

}

void loop() {
/*
// RESET device
  delay(1000);
  SetPointer(0xD3, 0x04);
  delay(1000);
*/  

//Start Measurement
  Wire1.beginTransmission(Address);
  Wire1.write(0x00);
  Wire1.write(0x10);
  Wire1.write(0x03);
  Wire1.write(0x00);
  uint8_t data[2]={0x03, 0x00};
  Wire1.write(CalcCrc(data));
  Wire1.endTransmission();
  
  delay(10000);
/*
//Start Fan Cleaning
  Serial.println("clean");
  Start fan cleaning
  SetPointer(0x56, 0x07);
  delay(12000);
  Serial.println("clean end");
  delay(100);
*/
 while(1){
  Serial.println(" ---------- ");
  //Read data ready flag
  SetPointer(0x02, 0x02);
  Wire1.requestFrom(Address, 3);
  w1=Wire1.read();
  w2=Wire1.read();
  w3=Wire1.read();


  if (w2==0x01){              //0x01: new measurements ready to read
    SetPointer(0x03,0x00);
    Wire1.requestFrom(Address, 60);
    for(int i=0;i<60;i++) { ND[i]=Wire1.read();                        
//    for(int i=0;i<30;i++) { ND[i]=Wire.read();     //without Wire.h lib modification only first 5 values
    //Serial.print(i);Serial.print(": ");Serial.println(ND[i],HEX);
    }
    // Result: PM1.0/PM2.5/PM4.0,PM10[μg/m³] , PM0.5,PM1.0/PM2.5/PM4.0,PM10 [[#/cm³], Typical Particle Size [μm]
    for(int i=0;i<60;i++) { 
       if ((i+1)%3==0)
       {
         byte datax[2]={ND[i-2], ND[i-1]};
         //Serial.print("crc: ");Serial.print(CalcCrc(datax),HEX);
         //Serial.print("  "); Serial.println(ND[i],HEX);
         if(tmp==0) {
           tmp= ND[i-2]; 
           tmp= (tmp<<8) + ND[i-1]; 
          }
         else{
           tmp= (tmp<<8)+ ND[i-2];
           tmp= (tmp<<8) + ND[i-1];
           //Serial.print(tmp,HEX);Serial.print(" ");
           measure= (*(float*) &tmp);
           Serial.print(measure); Serial.print(" ");
           tmp=0;
         }
         
       }
      }
      

  }
  Serial.println("");

  delay(2000);

 }

//  Stop Meaurement
//  SetPointer(0x01, 0x04);
 
}

void SetPointer(byte P1, byte P2)
{
  Wire1.beginTransmission(Address);
  Wire1.write(P1);
  Wire1.write(P2);
  Wire1.endTransmission();
  }


// from datasheet:
byte CalcCrc(byte data[2]) {
  byte crc = 0xFF;
  for(int i = 0; i < 2; i++) {    crc ^= data[i];    for(byte bit = 8; bit > 0; --bit) {
      if(crc & 0x80) {
      crc = (crc << 1) ^ 0x31u;
      } else {
        crc = (crc << 1);
       }
     }
   }
  return crc;
}