// Method to read a 16-bit value from a register and return it in little endian format
private UInt16 ReadUInt16_LittleEndian(byte register)
{
byte[] writeBuffer = new byte[] { register };
byte[] readBuffer = new byte[] { 0x00, 0x00 };
bme280.WriteRead(writeBuffer, readBuffer);
int h = readBuffer[1] << 8;
int l = readBuffer[0];
UInt16 value = (UInt16)(h + l);
return(value);
}
// Method to initialize the BME280 sensor using the I2C interface
public async Task InitializeDevice()
{
Debug.WriteLine("BME280::Initializing device with I2C interface");
try
{
bme280 = new I2CDevicePI(bus, BME280_Address);
if (bme280 == null) // Check if a device was found at the slave address provided by BME280_Address
{
Debug.WriteLine("Device not found");
return;
}
else // Since we found a device, let's verify that it is a BME280 by looking at the signature
{
Debug.WriteLine("BME280::Verifying device signature");
var WriteBuffer = new byte[] { (byte)Registers.BME280_REGISTER_CHIPID }; // This register stores the signature value
var ReadBuffer = new byte[] { 0xFF }; // Initialized to an arbitrary number
bme280.WriteRead(WriteBuffer, ReadBuffer); // Read the device signature and store in ReadBuffer[0]
if (ReadBuffer[0] != BME280_Signature) // Verify the device signature
{
Debug.WriteLine("BME280::Signature mismatch");
return;
}
Debug.WriteLine("BME280::Getting device ready");
// As per the data sheet's instructions, we need some stuff before we can
// start taking measurements using the BME280's registers.
await ReadCalibrationCoefficients(); // Read the compensation coefficients from the factory
await WriteControlRegister(); // Write to the control register
await WriteControlRegisterHumidity(); // Write to the humidity control register
Debug.WriteLine("BME280::Device is ready");
}
init = true;
}
catch (Exception e)
{
Debug.WriteLine("Exception: " + e.Message + "\n" + e.StackTrace);
throw;
}
}