Cleanup for 1.1.0 release

adafruit · Oct 1, 2018 · 0042e4e · 0042e4e
1 parent 98e6872
commit 0042e4e
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Showing 4 changed files with 158 additions and 98 deletions.
diff --git a/Adafruit_HTU21DF.cpp b/Adafruit_HTU21DF.cpp
@@ -1,100 +1,144 @@
-/*************************************************** 
+/***************************************************
   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  
+  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 
+  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.  
+  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() {
+/**
+* Constructor for the HTU21DF driver.
+ */
+Adafruit_HTU21DF::Adafruit_HTU21DF()
+{
+    /* Assign default values to internal tracking variables. */
+    _last_humidity = 0.0f;
+    _last_temp = 0.0f;
 }
 
+/**
+ * Initialises the I2C transport, and configures the IC for normal operation.
+ *
+ * @return true (1) if the device was successfully initialised, otherwise
+ *         false (0).
+ */
+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
+}
 
-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
+/**
+ * Sends a 'reset' request to the HTU21DF, followed by a 15ms delay.
+ */
+void Adafruit_HTU21DF::reset(void)
+{
+    Wire.beginTransmission(HTU21DF_I2CADDR);
+    Wire.write(HTU21DF_RESET);
+    Wire.endTransmission();
+    delay(15);
 }
 
-void Adafruit_HTU21DF::reset(void) {
-  Wire.beginTransmission(HTU21DF_I2CADDR);
-  Wire.write(HTU21DF_RESET);
-  Wire.endTransmission();
-  delay(15);
+/**
+ * Performs a single temperature conversion in degrees Celsius.
+ *
+ * @return a single-precision (32-bit) float value indicating the measured
+ *         temperature in degrees Celsius.
+ */
+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!
+
+    uint8_t count = Wire.requestFrom(HTU21DF_I2CADDR, 3);
+
+    /* Make sure we got 3 bytes back. */
+    if (count != 3) {
+        return 0.0f;
+    }
+
+    /* Read 16 bits of data, dropping the last two status bits. */
+    uint16_t t = Wire.read();
+    t <<= 8;
+    t |= Wire.read() & 0b11111100;
+
+    uint8_t crc = Wire.read();
+    (void)crc;
+
+    float temp = t;
+    temp *= 175.72f;
+    temp /= 65536.0f;
+    temp -= 46.85f;
+
+    /* Track the value internally in case we need to access it later. */
+    _last_temp = temp;
+
+    return temp;
 }
 
+/**
+ * Performs a single relative humidity conversion.
+ *
+ * @return A single-precision (32-bit) float value indicating the relative
+ *         humidity in percent (0..100.0%).
+ */
+float Adafruit_HTU21DF::readHumidity(void) {
+    /* Prepare the I2C request. */
+    Wire.beginTransmission(HTU21DF_I2CADDR);
+    Wire.write(HTU21DF_READHUM);
+    Wire.endTransmission();
 
-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()) {}
+    /* Wait a bit for the conversion to complete. */
+    delay(50);
 
-  uint16_t t = Wire.read();
-  t <<= 8;
-  t |= Wire.read();
+    /* Read the conversion results. */
+    uint8_t count = Wire.requestFrom(HTU21DF_I2CADDR, 3);
 
-  uint8_t crc = Wire.read();
+    /* Make sure we got 3 bytes back. */
+    if (count != 3) {
+        return 0.0f;
+    }
 
-  float temp = t;
-  temp *= 175.72;
-  temp /= 65536;
-  temp -= 46.85;
+    /* Read 16 bits of data, dropping the last two status bits. */
+    uint16_t h = Wire.read();
+    h <<= 8;
+    h |= Wire.read() & 0b11111100;
 
-  return temp;
-}
-
+    uint8_t crc = Wire.read();
+    (void)crc;
 
-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;
-}
+    float hum = h;
+    hum *= 125.0f;
+    hum /= 65536.0f;
+    hum -= 6.0f;
 
+    /* Track the value internally in case we need to access it later. */
+    _last_humidity = hum;
 
-
-/*********************************************************************/
+    return hum;
+}
diff --git a/Adafruit_HTU21DF.h b/Adafruit_HTU21DF.h
@@ -1,16 +1,16 @@
-/*************************************************** 
+/***************************************************
   This is a library for the HTU21D-F Humidity & Temp Sensor
 
   Designed specifically to work with the HTU21D-F sensor from Adafruit
   ----> https://www.adafruit.com/products/1899
 
-  These displays use I2C to communicate, 2 pins are required to  
+  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 
+  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.  
+  Written by Limor Fried/Ladyada for Adafruit Industries.
   BSD license, all text above must be included in any redistribution
  ****************************************************/
 
@@ -24,25 +24,39 @@
 #endif
 #include "Wire.h"
 
-#define HTU21DF_I2CADDR       0x40
-#define HTU21DF_READTEMP      0xE3
-#define HTU21DF_READHUM       0xE5
-#define HTU21DF_WRITEREG       0xE6
-#define HTU21DF_READREG       0xE7
-#define HTU21DF_RESET       0xFE
+/** Default I2C address for the HTU21D. */
+#define HTU21DF_I2CADDR         (0x40)
 
+/** Read temperature register. */
+#define HTU21DF_READTEMP        (0xE3)
 
+/** Read humidity register. */
+#define HTU21DF_READHUM         (0xE5)
 
+/** Write register command. */
+#define HTU21DF_WRITEREG        (0xE6)
+
+/** Read register command. */
+#define HTU21DF_READREG         (0xE7)
+
+/** Reset command. */
+#define HTU21DF_RESET           (0xFE)
+
+/**
+ * Driver for the Adafruit HTU21DF breakout board.
+ */
 class Adafruit_HTU21DF {
- public:
-  Adafruit_HTU21DF();
-  boolean begin(void);
-  float readTemperature(void);
-  float readHumidity(void);
-  void reset(void);
- private:
-  boolean readData(void);
-  float humidity, temp;
+    public:
+        Adafruit_HTU21DF();
+
+        boolean begin(void);
+        float   readTemperature(void);
+        float   readHumidity(void);
+        void    reset(void);
+
+    private:
+        boolean readData(void);
+        float _last_humidity, _last_temp;
 };
 
-#endif
+#endif /* _ADAFRUIT_HTU21DF_H */
diff --git a/examples/HTU21DFtest/HTU21DFtest.ino b/examples/HTU21DFtest/HTU21DFtest.ino
@@ -1,10 +1,10 @@
-/*************************************************** 
+/***************************************************
   This is an example for the HTU21D-F Humidity & Temp Sensor
 
   Designed specifically to work with the HTU21D-F sensor from Adafruit
   ----> https://www.adafruit.com/products/1899
 
-  These displays use I2C to communicate, 2 pins are required to  
+  These displays use I2C to communicate, 2 pins are required to
   interface
  ****************************************************/
 
@@ -28,9 +28,11 @@ void setup() {
   }
 }
 
-
 void loop() {
-  Serial.print("Temp: "); Serial.print(htu.readTemperature());
-  Serial.print("\t\tHum: "); Serial.println(htu.readHumidity());
-  delay(500);
-}
+    float temp = htu.readTemperature();
+    float rel_hum = htu.readHumidity();
+    Serial.print("Temp: "); Serial.print(temp); Serial.print(" C");
+    Serial.print("\t\t");
+    Serial.print("Humidity: "); Serial.print(rel_hum); Serial.println(" \%");
+    delay(500);
+}
diff --git a/library.properties b/library.properties
@@ -1,5 +1,5 @@
 name=Adafruit HTU21DF Library
-version=1.0.1
+version=1.1.0
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library for the HTU21D-F sensors in the Adafruit shop