private Func <Int16, double> GetTemperatureConversionFunc()
{
byte tempRawMsb = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.T1_T0 + 0x80, "Failed to read HTS221 T1_T0");
byte temp0Lsb = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.T0_C_8 + 0x80, "Failed to read HTS221 T0_C_8");
UInt16 T0_C_8 = (UInt16)((((UInt16)tempRawMsb & 0x03) << 8) | (UInt16)temp0Lsb);
double T0 = T0_C_8 / 8.0;
byte temp1Lsb = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.T1_C_8 + 0x80, "Failed to read HTS221 T1_C_8");
UInt16 T1_C_8 = (UInt16)(((UInt16)(tempRawMsb & 0x0C) << 6) | (UInt16)temp1Lsb);
double T1 = T1_C_8 / 8.0;
Int16 T0_OUT = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.T0_OUT + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 T0_OUT");
Int16 T1_OUT = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.T1_OUT + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 T1_OUT");
// Temperature calibration slope
double m = (T1 - T0) / (T1_OUT - T0_OUT);
// Temperature calibration y intercept
double b = T0 - (m * T0_OUT);
return(rawTemperature => rawTemperature * m + b);
}
/// <summary>
/// Tries to update the readings.
/// Returns true if new readings are available, otherwise false.
/// An exception is thrown if something goes wrong.
/// </summary>
public override bool Update()
{
var readings = new SensorReadings
{
Timestamp = DateTime.Now
};
byte status = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.STATUS, "Failed to read HTS221 status");
if ((status & 0x02) == 0x02)
{
Int16 rawHumidity = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.HUMIDITY_OUT_L + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 humidity");
readings.Humidity = _humidityConversionFunc(rawHumidity);
readings.HumidityValid = true;
}
if ((status & 0x01) == 0x01)
{
Int16 rawTemperature = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.TEMP_OUT_L + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 temperature");
readings.Temperature = _temperatureConversionFunc(rawTemperature);
readings.TemperatureValid = true;
}
if (readings.HumidityValid || readings.TemperatureValid)
{
AssignNewReadings(readings);
return(true);
}
return(false);
}
/// <summary>
/// Tries to update the readings.
/// Returns true if new readings are available, otherwise false.
/// An exception is thrown if something goes wrong.
/// </summary>
public override bool Update()
{
byte status = I2CSupport.Read8Bits(_i2CDevice, LPS25HDefines.STATUS_REG, "Failed to read LPS25H status");
var readings = new SensorReadings
{
Timestamp = DateTime.Now
};
if ((status & 0x02) == 0x02)
{
Int32 rawPressure = (Int32)I2CSupport.Read24Bits(_i2CDevice, LPS25HDefines.PRESS_OUT_XL + 0x80, ByteOrder.LittleEndian, "Failed to read LPS25H pressure");
readings.Pressure = rawPressure / 4096.0;
readings.PressureValid = true;
}
if ((status & 0x01) == 0x01)
{
Int16 rawTemperature = (Int16)I2CSupport.Read16Bits(_i2CDevice, LPS25HDefines.TEMP_OUT_L + 0x80, ByteOrder.LittleEndian, "Failed to read LPS25H temperature");
readings.Temperature = rawTemperature / 480.0 + 42.5;
readings.TemperatureValid = true;
}
if (readings.PressureValid || readings.TemperatureValid)
{
AssignNewReadings(readings);
return(true);
}
return(false);
}
private Func <Int16, double> GetHumidityConversionFunc()
{
byte H0_H_2 = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.H0_H_2 + 0x80, "Failed to read HTS221 H0_H_2");
double H0 = H0_H_2 / 2.0;
byte H1_H_2 = I2CSupport.Read8Bits(_i2CDevice, HTS221Defines.H1_H_2 + 0x80, "Failed to read HTS221 H1_H_2");
double H1 = H1_H_2 / 2.0;
Int16 H0_T0_OUT = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.H0_T0_OUT + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 H0_T_OUT");
Int16 H1_T0_OUT = (Int16)I2CSupport.Read16Bits(_i2CDevice, HTS221Defines.H1_T0_OUT + 0x80, ByteOrder.LittleEndian, "Failed to read HTS221 H1_T_OUT");
// Humidity calibration slope
double m = (H1 - H0) / (H1_T0_OUT - H0_T0_OUT);
// Humidity calibration y intercept
double b = H0 - (m * H0_T0_OUT);
return(rawHumidity => rawHumidity * m + b);
}
