BMP280 (気温・気圧センサー)

#include ＜Wire.h＞

#define BMP280_ADDR     0x77
#define BMP280_ID       0xD0
#define BMP280_RESET    0xE0
#define BMP280_CONTROL  0xF4
#define BMP280_PRESSURE 0xF7
#define BMP280_TEMP     0xFA

#define BMP280_DIG_T1    0x88
#define BMP280_DIG_T2    0x8A
#define BMP280_DIG_T3    0x8C
#define BMP280_DIG_P1    0x8E
#define BMP280_DIG_P2    0x90
#define BMP280_DIG_P3    0x92
#define BMP280_DIG_P4    0x94
#define BMP280_DIG_P5    0x96
#define BMP280_DIG_P6    0x98
#define BMP280_DIG_P7    0x9A
#define BMP280_DIG_P8    0x9C
#define BMP280_DIG_P9    0x9E

#define BMP280_T1 bmp280DIG[0]
#define BMP280_T2 bmp280DIG[1]
#define BMP280_T3 bmp280DIG[2]
#define BMP280_P1 bmp280DIG[3]
#define BMP280_P2 bmp280DIG[4]
#define BMP280_P3 bmp280DIG[5]
#define BMP280_P4 bmp280DIG[6]
#define BMP280_P5 bmp280DIG[7]
#define BMP280_P6 bmp280DIG[8]
#define BMP280_P7 bmp280DIG[9]
#define BMP280_P8 bmp280DIG[10]
#define BMP280_P9 bmp280DIG[11]

uint16_t bmp280DIG[12] ; // 0-3 : T1-T3 / 3-11 : P1-P9
int32_t t_fine;

char str[120] ;

// 1バイトコマンドを送信
void sendBMP280(uint8_t addr , uint8_t command) {
  Wire.beginTransmission(BMP280_ADDR);
  Wire.write(addr);
  Wire.write(command);
  Wire.endTransmission();
}

// センサー読み取り
uint32_t readBMP32b20(uint8_t addr) {
  uint32_t sensorData = 0 ;
  uint8_t readData ;

  // Read Address Set
  Wire.beginTransmission(BMP280_ADDR);
  Wire.write(addr);
  Wire.endTransmission();
  
  // 3Byte Read
  Wire.requestFrom(BMP280_ADDR, 3);
  while(Wire.available()＜3);
  readData = Wire.read();
  sensorData = readData ;
  readData = Wire.read();
  sensorData = (sensorData ＜＜ 8) | readData ;
  readData = Wire.read();
  sensorData = (sensorData ＜＜ 8) | readData ;
  sensorData ＞＞= 4 ;

  return sensorData ;
}

// 補正値読み取り
uint16_t readBMP32b16LE(uint8_t addr) {
  uint16_t readData ;
  // Read Address Set
  Wire.beginTransmission(BMP280_ADDR);
  Wire.write(addr);
  Wire.endTransmission();
  
  // 2Byte Read
  Wire.requestFrom(BMP280_ADDR, 2);
  while(Wire.available()＜2);
  uint8_t d1 = Wire.read();
  uint8_t d2 = Wire.read();
  readData = d2 ＜＜ 8 | d1 ;
  // ▼ こんな書き方も出来るけど…あまりお勧めしない
  // ▼ 何をやってるのか直感的に分かりにくいから
  // ((uint8_t *)&readData)[0] = d1 ;
  // ((uint8_t *)&readData)[1] = d2 ;

  return readData ;
}

// Register読み取り
uint8_t readBMP32b8(uint8_t addr) {
  uint8_t readData ;
  // Read Address Set
  Wire.beginTransmission(BMP280_ADDR);
  Wire.write(addr);
  Wire.endTransmission();
  
  // 1Byte Read
  Wire.requestFrom(BMP280_ADDR, 1);
  while(Wire.available()＜1);
  readData = Wire.read();

  return readData ;
}

// 温度読み取り
int32_t readBMP32Tmp() {
  uint32_t temData = readBMP32b20(BMP280_TEMP) ;

  // ----- DATA 補正 -----
  int32_t var1, var2;
  uint16_t t1 = BMP280_T1 ;
  int16_t t2 = (int16_t)BMP280_T2,t3=(int16_t)BMP280_T3 ;
  var1 = (((temData ＞＞ 3) - ((int32_t)(t1 ＜＜ 1))) * ((int32_t)t2)) ＞＞ 11;
  var2 = (((((temData ＞＞ 4) - ((int32_t)t1)) * ((temData ＞＞ 4) - ((int32_t)t1))) ＞＞ 12) * ((int32_t)t3)) ＞＞ 14;

  t_fine = var1 + var2;
  temData = (t_fine * 5 + 128) ＞＞ 8;

  return temData ;
}

// 気圧読み取り
int32_t readBMP32Pre() {
  readBMP32Tmp(); // 気温センサー読み取り
  uint32_t preData = readBMP32b20(BMP280_PRESSURE) ; // 気圧センサー読み取り

  // ----- DATA 補正 -----
  int64_t var1, var2 , p;
  uint16_t p1 = BMP280_P1 ;
  int16_t p2 = (int16_t)BMP280_P2,p3=(int16_t)BMP280_P3 ;
  int16_t p4 = (int16_t)BMP280_P4,p5=(int16_t)BMP280_P5 ;
  int16_t p6 = (int16_t)BMP280_P6,p7=(int16_t)BMP280_P7 ;
  int16_t p8 = (int16_t)BMP280_P8,p9=(int16_t)BMP280_P9 ;

  var1 = ((int64_t)t_fine) - 128000;
  var2 = var1 * var1 * (int64_t)p6;
  var2 = var2 + ((var1*(int64_t)p5)＜＜17);
  var2 = var2 + (((int64_t)p4)＜＜35);
  var1 = ((var1 * var1 * (int64_t)p3)＞＞8) + ((var1 * (int64_t)p2)＜＜12);
  var1 = (((((int64_t)1)＜＜47)+var1))*((int64_t)p1)＞＞33;
  if (var1 == 0) {
    return 0; // avoid exception caused by division by zero
  }

  p = 1048576-preData;
  p = (((p＜＜31)-var2)*3125)/var1;
  var1 = (((int64_t)p9) * (p＞＞13) * (p＞＞13)) ＞＞ 25;
  var2 = (((int64_t)p8) * p) ＞＞ 19;
  p = ((p + var1 + var2) ＞＞ 8) + (((int64_t)p7)＜＜4);

  preData = (uint32_t)p /256 ;

  return preData ;
}


void setup() {
  Serial.begin(9600);
  Wire.begin();

   Serial.println("START");
  // BMP280リセット
  sendBMP280(BMP280_RESET,0xB6) ;
  delay(4) ;  // 通常軌道に2m秒を要するので、多めに4m秒待ってみる

  if (readBMP32b8(BMP280_ID) != 0x58) { // デバイスIDチェック
     Serial.println("Device is not BMP280"); // チェックする必要はない気がする、間違う奴はおらんやろう
  }
   Serial.println("CHECK ID - OK");

  // 補正データ読み出し
  BMP280_T1 = readBMP32b16LE(BMP280_DIG_T1) ;
  BMP280_T2 = readBMP32b16LE(BMP280_DIG_T2) ;
  BMP280_T3 = readBMP32b16LE(BMP280_DIG_T3) ;
  sprintf(str,"dig_T1=%d",BMP280_T1) ;  Serial.println(str) ;
  sprintf(str,"dig_T2=%d",BMP280_T2) ;  Serial.println(str) ;
  sprintf(str,"dig_T3=%d",BMP280_T3) ;  Serial.println(str) ;

  BMP280_P1 = readBMP32b16LE(BMP280_DIG_P1) ;
  BMP280_P2 = readBMP32b16LE(BMP280_DIG_P2) ;
  BMP280_P3 = readBMP32b16LE(BMP280_DIG_P3) ;
  BMP280_P4 = readBMP32b16LE(BMP280_DIG_P4) ;
  BMP280_P5 = readBMP32b16LE(BMP280_DIG_P5) ;
  BMP280_P6 = readBMP32b16LE(BMP280_DIG_P6) ;
  BMP280_P7 = readBMP32b16LE(BMP280_DIG_P7) ;
  BMP280_P8 = readBMP32b16LE(BMP280_DIG_P8) ;
  BMP280_P9 = readBMP32b16LE(BMP280_DIG_P9) ;

  // 動作モード設定
  sendBMP280(BMP280_CONTROL,0b00111111) ; // 001:温度の解像度　111：気圧の解像度　11:動作モード(ノーマルモード)
}

void loop() {
  long tmp = readBMP32Tmp() ;
  int tn=tmp/100 ;
  int td=tmp%100 ;
  sprintf(str,"%d.%02d℃  ",tn,td) ;
  Serial.print(str) ;

  long pre = readBMP32Pre() ;
  sprintf(str,"%dhPa",pre/100) ;
  Serial.println(str) ;

  delay(3000) ;
  
}