  * DHT11/22 - 1 unit,
  * DS18B20  - 3 units,
  * 
- * Communicates using Modbus RTU:
- * Holding Registers (4x) 40001 - 40010
+ * Supports Modbus RTU.
+ * Holding Registers (4X), function 03H.
+ * Register address 1 corresponds to the physical address 0.
+ * 
+ * Register  Type   Description
+ * 01-02     Float  Pressure (BMP280)
+ * 03-04     Float  Temperature (BMP280)
+ * 05-06     Float  Humidity (DHT22)
+ * 06-08     Float  Temperature (DHT22)
+ * 07-10     Float  Temerature 0 (DS18B20)
+ * 08-12     Float  Temerature 1 (DS18B20)
+ * 11-14     Float  Temerature 2 (DS18B20)
  * 
  * (c) 2017-2019, Mikhail Shiryaev
  */
 
+#include <Adafruit_BMP280.h>   // https://github.com/adafruit/Adafruit_BMP280_Library
 #include <DHT.h>               // https://github.com/adafruit/DHT-sensor-library
 #include <OneWire.h>           // http://www.pjrc.com/teensy/td_libs_OneWire.html
 #include <DallasTemperature.h> // https://github.com/milesburton/Arduino-Temperature-Control-Library

  Serial.println(millis() - time);
}
#endif

// Read data from DHT sensor
void readDHT() {

  Serial.begin(9600);
  DEBUG_PRINTLN();
  DEBUG_PRINTLN("SERIAL TH meter started");
  initBMP();
  initDHT();
  initDS();
  DEBUG_PRINTLN();
