[General] UART communication protocol read with Arduino

void ProcessSerialData(){
  uint8_t mData = 0;
  uint8_t i = 0;
  uint8_t mPkt[10] = {0};
  uint8_t mCheck = 0;
  while (Serial.available() > 0){    
    // packet format: AA   C0   PM25_Low   PM25_High   PM10_Low   PM10_High   0   0   CRC   AB
    mData = Serial.read();     
    delay(2);                                   // wait until packet is received
       if (mData == 0xAA){               // head1 ok
       mPkt[0] =  mData;
           mData = Serial.read();
           if (mData == 0xc0){           // head2 ok
           mPkt[1] =  mData;
    mCheck = 0;
       for (i = 0; i < 6; i++){           // data recv and crc calc
       mPkt[i + 2] = Serial.read();
       delay(2);
       mCheck += mPkt[i + 2];
     }
        mPkt[8] = Serial.read();
        delay(1);
        mPkt[9] = Serial.read();
        if (mCheck == mPkt[8]){        // crc ok
          Serial2.flush();
          
        Pm25 = (uint16_t)mPkt[2] | (uint16_t)(mPkt[3] << 8);
        Pm10 = (uint16_t)mPkt[4] | (uint16_t)(mPkt[5] << 8);
        return;
        }
      }
    }
  }
}

void setup() {
  winsenBegin();
  Serial.begin(9600);
}

void loop() {
  float result = winsenRead();
  Serial.println(result, DEC);
}
/**
   Setup the Winsen sensor
*/
void winsenBegin() {
  Serial1.begin(9600);
  byte setConfig[] = {0xFF, 0x01, 0x78, 0x41, 0x00, 0x00, 0x00, 0x00, 0x46}; //Set 1 Q/A configuration
  Serial1.write(setConfig, sizeof(setConfig)); //
  delay(1000);// Wait for a response
  while (Serial1.available() > 0) { // Flush the response
    byte c = Serial1.read();
  }
}
/**
   Read the sensor
   @return {float} sensor [C]
*/
float winsenRead() {
  byte petition[] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79}; // Petition to get a single result
  byte measure[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; // Space for the response
  float ppm;
  Serial1.write(petition, sizeof(petition));
  delay(2000);
  if (Serial1.available() > 0) {
    Serial1.readBytes(measure, 9);
    if (measure[0] == 0xff && measure[1] == 0x78) {
      Serial1.readBytes(measure, 9);
    }

    if (measure[0] == 0xff && measure[1] == 0x86) {
      ppm = (measure[2] * 256 + measure[3]) * 0.1; // this formula depends of the sensor is in the dataSheet
    } else {
      ppm = -1;
    }
  }
  return ppm;
}

packetReceived = 0;
while(!packetReceived)
{
    readIndex = 0;
    while(readIndex == 0)
    {
        if(Serial1.available())  // Wait until a character is available
        {
            measure[readIndex] = Serial1.read();  // Read it in
            if( 0xAA == measure[readIndex])         // Is it the start of a header
            {
                 readIndex++;                             // Yes - increment the pointer
                 break;                                       // Break out of the while loop
            }
        }     // Still not seen a valid header so keep on looking
    }
    // We have a valid header character - read in the rest of the packet
    while( readIndex < 10)
    {
        if( Serial1.available())    // Wait until the character is available
        {
            message[readIndex] = Serial1.read();   // Read the character
            if( readIndex == 1)
            {
                // Check that the second character is the expected command ID
                if( message[readIndex] != 0xc0)
                { break; }   // It is not the expected character - something is wrong so dump this packet
            }
            if( readIndex == 9)
            {
                // Check that the end of the packet marker has been read
                if( message[readIndex] != 0xAB)
                { break; }        // Not the expected message tail - dump the packet
                else
                { packetReceived = 1; }  // Show that we have a complete packet
            }
            readIndex++;
        }
    }
}
// When you get here you know you have a complete and valid packet