/// <summary>
/// Force the sensor to make a reading and update the relevanyt properties.
/// </summary>
/// <param name="startAddress">Start address for the read operation.</param>
/// <param name="amount">Amount of data to read from the EEPROM.</param>
public byte[] Read(ushort startAddress, ushort amount)
{
CheckAddress(startAddress, amount);
var address = new byte[2];
address[0] = (byte)((startAddress >> 8) & 0xff);
address[1] = (byte)(startAddress & 0xff);
_eeprom.WriteBytes(address);
return(_eeprom.ReadBytes(amount));
}
/// <summary>
/// Send a command to the display.
/// </summary>
/// <param name="command">Command byte to send to the display.</param>
private void SendCommand(byte command)
{
if (connectionType == ConnectionType.SPI)
{
dataCommandPort.State = Command;
spiDisplay.WriteByte(command);
}
else
{
i2cPeriferal.WriteBytes(new byte[] { 0x00, command });
}
}
/// <summary>
/// Send a command to the display.
/// </summary>
/// <param name="command">Command byte to send to the display.</param>
protected virtual void SendCommand(byte command)
{
if (connectionType == ConnectionType.SPI)
{
dataCommandPort.State = Command;
_spiPeripheral.WriteByte(command);
}
else
{
_I2cPeripheral.WriteBytes(new byte[] { 0x00, command });
}
}
/// <summary>
/// Update the temperature and pressure from the sensor and set the Pressure property.
/// </summary>
public async Task Update()
{
//
// Tell the sensor to take a temperature and pressure reading, wait for
// 3ms (see section 2.2 of the datasheet) and then read the ADC values.
//
mpl115a2.WriteBytes(new byte[] { Registers.StartConversion, 0x00 });
await Task.Delay(5);
var data = mpl115a2.ReadRegisters(Registers.PressureMSB, 4);
//
// Extract the sensor data, note that this is a 10-bit reading so move
// the data right 6 bits (see section 3.1 of the datasheet).
//
var pressure = (ushort)(((data[0] << 8) + data[1]) >> 6);
var temperature = (ushort)(((data[2] << 8) + data[3]) >> 6);
Conditions.Temperature = (float)((temperature - 498.0) / -5.35) + 25;
//
// Now use the calculations in section 3.2 to determine the
// current pressure reading.
//
const double PRESSURE_CONSTANT = 65.0 / 1023.0;
var compensatedPressure = coefficients.A0 + ((coefficients.B1 + (coefficients.C12 * temperature))
* pressure) + (coefficients.B2 * temperature);
Conditions.Pressure = (float)(PRESSURE_CONSTANT * compensatedPressure) + 50;
}
//Set sensor resolution
/*******************************************************************************************/
//Sets the sensor resolution to one of four levels
//Page 12:
// 0/0 = 12bit RH, 14bit Temp
// 0/1 = 8bit RH, 12bit Temp
// 1/0 = 10bit RH, 13bit Temp
// 1/1 = 11bit RH, 11bit Temp
//Power on default is 0/0
void SetResolution(SensorResolution resolution)
{
byte userData = si7021.ReadRegister(READ_USER_REGISTER); //Go get the current register state
//userRegister &= 0b01111110; //Turn off the resolution bits
//resolution &= 0b10000001; //Turn off all other bits but resolution bits
//userRegister |= resolution; //Mask in the requested resolution bits
var res = (byte)resolution;
userData &= 0x73; //Turn off the resolution bits
res &= 0x81; //Turn off all other bits but resolution bits
userData |= res; //Mask in the requested resolution bits
//Request a write to user register
si7021.WriteBytes(new byte[] { WRITE_USER_REGISTER }); //Write to the user register
si7021.WriteBytes(new byte[] { userData }); //Write the new resolution bits
}
private async Task Update()
{
byte[] readBuffer;
BitArray bufferBits;
//Send the command to the sensor to tell it to do the thing.
i2cPeripheral.WriteBytes(mprlsMeasurementCommand);
//Datasheet says wait 5 ms.
await Task.Delay(5);
while (true)
{
readBuffer = i2cPeripheral.ReadBytes(1);
bufferBits = new BitArray(readBuffer);
//From section 6.5 of the datasheet.
this.IsDevicePowered = bufferBits[6];
this.IsDeviceBusy = bufferBits[5];
this.HasMemoryIntegrityFailed = bufferBits[2];
this.InternalMathSaturated = bufferBits[0];
if (this.InternalMathSaturated)
{
throw new InvalidOperationException("Sensor pressure has exceeded max value!");
}
if (this.HasMemoryIntegrityFailed)
{
throw new InvalidOperationException("Sensor internal memory integrity check failed!");
}
if (!(this.IsDeviceBusy))
{
break;
}
}
readBuffer = i2cPeripheral.ReadBytes(4);
RawPSIMeasurement = (readBuffer[1] << 16) | (readBuffer[2] << 8) | readBuffer[3];
//Console.WriteLine(RawPSIMeasurement);
//From Section 8.0 of the datasheet.
CalculatedPSIMeasurement = (RawPSIMeasurement - 1677722) * (psiMax - psiMin);
//Console.WriteLine(CalculatedPSIMeasurement);
CalculatedPSIMeasurement /= 15099494 - 1677722;
//Console.WriteLine(CalculatedPSIMeasurement);
CalculatedPSIMeasurement += psiMin;
//Console.WriteLine(CalculatedPSIMeasurement);
//https://www.justintools.com/unit-conversion/pressure.php?k1=psi&k2=millibars
CalculatedhPAMeasurement = CalculatedPSIMeasurement * 68.947572932;
//Console.WriteLine(CalculatedhPAMeasurement);
Conditions.Pressure = CalculatedPSIMeasurement;
}
private long ReadUncompensatedTemperature()
{
// write register address
bmp085.WriteBytes(new byte[] { 0xF4, 0x2E });
// Required as per datasheet.
Thread.Sleep(5);
// write register address
bmp085.WriteBytes(new byte[] { 0xF6 });
// get MSB and LSB result
byte[] data = new byte[2];
data = bmp085.ReadBytes(2);
return((data[0] << 8) | data[1]);
}
/// <summary>
/// Get ASG01DB VOC Gas Concentration
/// </summary>
/// <returns>Concentration (ppm)</returns>
public double GetConcentration()
{
var data = new byte[] { ASG_DATA_MSB, ASG_DATA_LSB };
sensor.WriteBytes(data);
var readBuffer = sensor.ReadBytes(3);
// CRC check
// if (!CheckCrc8(readBuffer, 2, readBuffer[1]))
// {
// return -1;
// }
ushort res = BinaryPrimitives.ReadUInt16BigEndian(readBuffer.AsSpan(0, 2));
return(res / 10.0);
}
public byte[] Execute(int returnBytes, out UInt16 ResultCode)
{
lock (lockObject)
{
sas.WriteBytes(WriteBufferData);
#if DEBUGSERIAL
Console.WriteLine($"TX: {BitConverter.ToString(WriteBufferData,0,WriteBufferData.Length)}");
#endif
return(Read(returnBytes, out ResultCode));
}
}
void TransmitData()
{
i2cPeripheral.WriteBytes(transmissionData);
Thread.Sleep(100);
}
