101 lines
2.2 KiB
C++
101 lines
2.2 KiB
C++
|
/***************************************************
|
||
|
|
This is a library for the HTU21DF Humidity & Temp Sensor
|
||
|
|
|
||
|
|
Designed specifically to work with the HTU21DF sensor from Adafruit
|
||
|
|
----> https://www.adafruit.com/products/1899
|
||
|
|
|
||
|
|
These displays use I2C to communicate, 2 pins are required to
|
||
|
|
interface
|
||
|
|
Adafruit invests time and resources providing this open source code,
|
||
|
|
please support Adafruit and open-source hardware by purchasing
|
||
|
|
products from Adafruit!
|
||
|
|
|
||
|
|
Written by Limor Fried/Ladyada for Adafruit Industries.
|
||
|
|
BSD license, all text above must be included in any redistribution
|
||
|
|
****************************************************/
|
||
|
|
|
||
|
|
#include "Adafruit_HTU21DF.h"
|
||
|
|
#if defined(__AVR__)
|
||
|
|
#include <util/delay.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
Adafruit_HTU21DF::Adafruit_HTU21DF() {
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
boolean Adafruit_HTU21DF::begin(void) {
|
||
|
|
Wire.begin();
|
||
|
|
|
||
|
|
reset();
|
||
|
|
|
||
|
|
Wire.beginTransmission(HTU21DF_I2CADDR);
|
||
|
|
Wire.write(HTU21DF_READREG);
|
||
|
|
Wire.endTransmission();
|
||
|
|
Wire.requestFrom(HTU21DF_I2CADDR, 1);
|
||
|
|
return (Wire.read() == 0x2); // after reset should be 0x2
|
||
|
|
}
|
||
|
|
|
||
|
|
void Adafruit_HTU21DF::reset(void) {
|
||
|
|
Wire.beginTransmission(HTU21DF_I2CADDR);
|
||
|
|
Wire.write(HTU21DF_RESET);
|
||
|
|
Wire.endTransmission();
|
||
|
|
delay(15);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
float Adafruit_HTU21DF::readTemperature(void) {
|
||
|
|
|
||
|
|
// OK lets ready!
|
||
|
|
Wire.beginTransmission(HTU21DF_I2CADDR);
|
||
|
|
Wire.write(HTU21DF_READTEMP);
|
||
|
|
Wire.endTransmission();
|
||
|
|
|
||
|
|
delay(50); // add delay between request and actual read!
|
||
|
|
|
||
|
|
Wire.requestFrom(HTU21DF_I2CADDR, 3);
|
||
|
|
while (!Wire.available()) {}
|
||
|
|
|
||
|
|
uint16_t t = Wire.read();
|
||
|
|
t <<= 8;
|
||
|
|
t |= Wire.read();
|
||
|
|
|
||
|
|
uint8_t crc = Wire.read();
|
||
|
|
|
||
|
|
float temp = t;
|
||
|
|
temp *= 175.72;
|
||
|
|
temp /= 65536;
|
||
|
|
temp -= 46.85;
|
||
|
|
|
||
|
|
return temp;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
float Adafruit_HTU21DF::readHumidity(void) {
|
||
|
|
// OK lets ready!
|
||
|
|
Wire.beginTransmission(HTU21DF_I2CADDR);
|
||
|
|
Wire.write(HTU21DF_READHUM);
|
||
|
|
Wire.endTransmission();
|
||
|
|
|
||
|
|
delay(50); // add delay between request and actual read!
|
||
|
|
|
||
|
|
Wire.requestFrom(HTU21DF_I2CADDR, 3);
|
||
|
|
while (!Wire.available()) {}
|
||
|
|
|
||
|
|
uint16_t h = Wire.read();
|
||
|
|
h <<= 8;
|
||
|
|
h |= Wire.read();
|
||
|
|
|
||
|
|
uint8_t crc = Wire.read();
|
||
|
|
|
||
|
|
float hum = h;
|
||
|
|
hum *= 125;
|
||
|
|
hum /= 65536;
|
||
|
|
hum -= 6;
|
||
|
|
|
||
|
|
return hum;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
/*********************************************************************/
|