Merge pull request #81 from finitespace/filtering

Filtering

src/BME280.cpp

@@ -53,6 +53,12 @@ bool BME280::Initialize()
  if(success)
  {
  success &= ReadTrim();
+
+ if(m_settings.filter != Filter_Off)
+ {
+ InitializeFilter();
+ }
+
  WriteSettings();
  }
 
@@ -61,6 +67,24 @@ bool BME280::Initialize()
  return m_initialized;
 }
 
+
+/****************************************************************/
+bool BME280::InitializeFilter()
+{
+ // Force an unfiltered measurement to populate the filter buffer.
+ // This fixes a bug that causes the first read to always be 28.82 °C 81732.34 hPa.
+ Filter filter = m_settings.filter;
+ m_settings.filter = Filter_Off;
+
+ WriteSettings();
+
+ float dummy;
+ read(dummy, dummy, dummy);
+
+ m_settings.filter = filter;
+}
+
+
 /****************************************************************/
 bool BME280::ReadChipID()
 {

src/BME280.h

@@ -205,10 +205,16 @@ class BME280
 /* CONSTRUCTOR INIT FUNCTIONS */
 /*****************************************************************/
 
- //////////////////////////////////////////////////////////////////
+ ///////////////////////////////////////////////////////////////
  /// Write configuration to BME280, return true if successful.
+ /// Must be called from any child classes.
  virtual bool Initialize();
 
+ ///////////////////////////////////////////////////////////////
+ /// Force a unfiltered measurement to populate the filter 
+ /// buffer.
+ bool InitializeFilter();
+
 
 /*****************************************************************/
 /* ACCESSOR FUNCTIONS */

src/BME280SpiSw.h

@@ -81,7 +81,8 @@ class BME280SpiSw: public BME280{
 protected:
 
  ////////////////////////////////////////////////////////////////
- /// Method used at start up to initialize the class. Starts the I2C interface.
+ /// Method used at start up to initialize the class. Starts the
+ /// software SPI interface.
  virtual bool Initialize();
 
 private: