public async Task <BMP180SensorData> ReadSensorDataAsync(BMP180AccuracyMode oss)
{
this.CheckState();
Debug.WriteLine("BMP180@{0:X} - Read Sensor Data", this.I2cAddress);
// Read the Uncompestated values from the sensor.
byte[] tData = await ReadUncompestatedTemperature();
byte[] pData = await ReadUncompestatedPressure(oss);
int ut = (tData[0] << 8) + tData[1];
double up = (pData[0] * 256.0) + pData[1] + (pData[2] / 256.0);
// Calculate real values
int b5 = calculateB5(ut);
int t = (b5 + 8) >> 4;
//double temperature = t / 10.0;
double temperature = (double)t / 10.0;
double s = temperature - 25.0;
double x = (x2 * Math.Pow(s, 2)) + (x1 * s) + x0;
double y = (y2 * Math.Pow(s, 2)) + (y1 * s) + y0;
double z = (up - x) / y;
double pressure = (p2 * Math.Pow(z, 2)) + (p1 * z) + p0;
return(new BMP180SensorData(temperature, pressure, tData, pData, oss));
}
public async Task <byte[]> ReadUncompestatedPressure(BMP180AccuracyMode ossMode)
{
this.CheckState();
byte pressureCommand = 0;
int delay = 5;
switch (ossMode)
{
case BMP180AccuracyMode.UltraLowPower:
pressureCommand = (byte)BMP180Commands.ReadPressureLowAccuracy;
delay = 5;
break;
case BMP180AccuracyMode.Standard:
pressureCommand = (byte)BMP180Commands.ReadPressureStandardAccuracy;
delay = 8;
break;
case BMP180AccuracyMode.HighResolution:
pressureCommand = (byte)BMP180Commands.ReadPressureHighAccuracy;
delay = 14;
break;
case BMP180AccuracyMode.UltraHighResolution:
pressureCommand = (byte)BMP180Commands.ReadPressureUltraHighAccuracy;
delay = 26;
break;
}
Debug.WriteLine("BMP180@{0:X} - Read Uncompensated Pressure {1:X} with mode {2:X}.", this.I2cAddress, pressureCommand, ossMode);
byte[] command = { (byte)BMP180Registers.Command, pressureCommand };
this.bmp180I2c.Write(command);
await Task.Delay(delay);
return(WriteRead(BMP180Registers.Result, 3));
}
/// <summary>
///
/// </summary>
/// <param name="Temperature"></param>
/// <param name="Pressure"></param>
/// <param name="UncompensatedTemperature"></param>
/// <param name="UncompensatedPressure"></param>
public BMP180SensorData(double temperature, double pressure, byte[] uncompensatedTemperature, byte[] uncompensatedPressure, BMP180AccuracyMode mode)
{
// Remove 11 degrees for heat offset from RPI.
// Probably more after case is installed.
this.Temperature = temperature - 11.0;
this.Pressure = pressure;
this.UncompensatedTemperature = uncompensatedTemperature;
this.UncompensatedPressure = uncompensatedPressure;
this.AccuracyMode = mode;
this.PressureAtSeaLevelHpa = 1013.25;
}
