public void ReadTemperatureTest()
{
List <byte> packet = new List <byte>();
var sht21 = new SHT21();
sht21.Reset();
// Start measurement, Temperature - hold master
packet.Add((byte)0xFD);
packet.Add((byte)0xE3);
sht21.Write(packet.ToArray());
packet.Clear();
// Read temperature sensor data result
packet.Add((byte)0xFC);
packet.Add((byte)0xE3);
sht21.Write(packet.ToArray());
packet.Clear();
byte[] temperatureBytes = sht21.Read();
// Check SHT21 CRC
// Check SHT21 CRC
byte[] resultArray = new byte[2] {
0, 0
};
resultArray[0] = temperatureBytes[0];
resultArray[1] = temperatureBytes[1];
byte checkCRC = GetSTH21CRC(resultArray, 2);
Assert.AreEqual(checkCRC, temperatureBytes[2]);
// Assemble data bytes - default precision value is 14 bit
UInt16 temperatureInt = (UInt16)((((int)temperatureBytes[0] << 6) & 0x3FC0) + (((int)temperatureBytes[1] & 0xFC) >> 2));
// Calculate temperature
// T = -46.85 + 175.72 * ST/2^16
double temperature = 17572.0 * Convert.ToDouble(temperatureInt) / 65536.0 - 46.85;
temperature = Math.Round(temperature, 2);
Assert.Greater(temperature, 0);
}
public void InitTest()
{
List <byte> packet = new List <byte>();
var sht21 = new SHT21();
sht21.Reset();
// Check the serial number in on-chip memory 1
// TODO: not fully implemented, now returns zeros
packet.Add((byte)0xFC);
packet.Add((byte)0xFA);
packet.Add((byte)0x0F);
sht21.Write(packet.ToArray());
packet.Clear();
byte[] serialNr = sht21.Read();
Assert.AreEqual(serialNr[0], 0x0);
Assert.AreEqual(serialNr[1], 0x0);
Assert.AreEqual(serialNr[2], 0x0);
Assert.AreEqual(serialNr[3], 0x0);
Assert.AreEqual(serialNr[4], 0x0);
Assert.AreEqual(serialNr[5], 0x0);
Assert.AreEqual(serialNr[6], 0x0);
Assert.AreEqual(serialNr[7], 0x0);
Assert.AreEqual(serialNr[8], 0x0);
// Check the serial number in on-chip memory 2
// TODO: not fully implemented, now returns zeros
packet.Add((byte)0xFD);
packet.Add((byte)0xFA);
packet.Add((byte)0xC9);
sht21.Write(packet.ToArray());
packet.Clear();
serialNr = sht21.Read();
Assert.AreEqual(serialNr[0], 0x0);
Assert.AreEqual(serialNr[1], 0x0);
Assert.AreEqual(serialNr[2], 0x0);
Assert.AreEqual(serialNr[3], 0x0);
Assert.AreEqual(serialNr[4], 0x0);
Assert.AreEqual(serialNr[5], 0x0);
Assert.AreEqual(serialNr[6], 0x0);
// Check the user register, write and read back
byte userWrite = 0xAA;
packet.Add((byte)0xFD);
packet.Add((byte)0xE6);
packet.Add(userWrite);
sht21.Write(packet.ToArray());
packet.Clear();
packet.Add((byte)0xFC);
packet.Add((byte)0xE7);
sht21.Write(packet.ToArray());
packet.Clear();
byte[] userRead = sht21.Read();
Assert.AreEqual(userRead[0], userWrite);
// Do a soft reset and check reset value of user register
packet.Add((byte)0xFD);
packet.Add((byte)0xFE);
packet.Add((byte)0x0);
sht21.Write(packet.ToArray());
packet.Clear();
packet.Add((byte)0xFC);
packet.Add((byte)0xE7);
sht21.Write(packet.ToArray());
packet.Clear();
userRead = sht21.Read();
Assert.AreEqual(userRead[0], 0x3A);
}
public void ReadHumidityTest()
{
List <byte> packet = new List <byte>();
var sht21 = new SHT21();
sht21.Reset();
////////////////////////////////////////////////////////////
// Start measurement, Relative Humidity - hold master - 12-bit resolution
packet.Add((byte)0xFD);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
// Read Relative Humidity sensor data result
packet.Add((byte)0xFC);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
byte[] humidityBytes = sht21.Read();
// Check SHT21 CRC
byte[] resultArray = new byte[2] {
0, 0
};
resultArray[0] = humidityBytes[0];
resultArray[1] = humidityBytes[1];
byte checkCRC = GetSTH21CRC(resultArray, 2);
Assert.AreEqual(checkCRC, humidityBytes[2]);
// Assemble data bytes - default precision value is 12 bit
UInt32 humidityInt = (UInt32)((((UInt16)humidityBytes[0] << 4) & 0xFF0) + (((UInt16)humidityBytes[1] >> 4) & 0xF));
// Calculate relative humidity
// RH = -6 + 125 * SRH/2^16
double humidity = 125.0 * Convert.ToDouble(humidityInt << 4) / 65536.0 - 6.0;
humidity = Math.Round(humidity, 1);
Assert.Greater(humidity, 0);
Assert.LessOrEqual(humidity, 100);
////////////////////////////////////////////////////////////
// Start measurement, Relative Humidity - hold master - 8-bit resolution
// Set 8-bit resolution
packet.Add((byte)0xFD);
packet.Add((byte)0xE6);
packet.Add((byte)0x3B);
sht21.Write(packet.ToArray());
packet.Clear();
// Start measurement
packet.Add((byte)0xFD);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
// Read Relative Humidity sensor data result
packet.Add((byte)0xFC);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
humidityBytes = sht21.Read();
// Check SHT21 CRC
resultArray = new byte[2] {
0, 0
};
resultArray[0] = humidityBytes[0];
resultArray[1] = humidityBytes[1];
checkCRC = GetSTH21CRC(resultArray, 2);
Assert.AreEqual(checkCRC, humidityBytes[2]);
// Assemble data bytes - precision value is 8 bit
humidityInt = (UInt32)(humidityBytes[0] & 0xFF);
// Calculate relative humidity
// RH = -6 + 125 * SRH/2^16
humidity = 125.0 * Convert.ToDouble(humidityInt << 8) / 65536.0 - 6.0;
//humidity *= 100;
humidity = Math.Round(humidity, 1);
Assert.Greater(humidity, 0);
Assert.LessOrEqual(humidity, 100);
// Start measurement, Relative Humidity - hold master - 8-bit resolution
// Set 10-bit resolution
packet.Add((byte)0xFD);
packet.Add((byte)0xE6);
packet.Add((byte)0xBA);
sht21.Write(packet.ToArray());
packet.Clear();
// Start measurement
packet.Add((byte)0xFD);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
// Read Relative Humidity sensor data result
packet.Add((byte)0xFC);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
humidityBytes = sht21.Read();
// Check SHT21 CRC
resultArray = new byte[2] {
0, 0
};
resultArray[0] = humidityBytes[0];
resultArray[1] = humidityBytes[1];
checkCRC = GetSTH21CRC(resultArray, 2);
Assert.AreEqual(checkCRC, humidityBytes[2]);
// Assemble data bytes - precision value is 10 bit
humidityInt = (UInt32)((((UInt16)humidityBytes[0] << 2) & 0x3FC) + (((UInt16)humidityBytes[1] >> 6) & 0x3));
// RH = -6 + 125 * SRH/2^16
humidity = 125.0 * Convert.ToDouble(humidityInt << 6) / 65536.0 - 6.0;
//humidity *= 100;
humidity = Math.Round(humidity, 1);
Assert.Greater(humidity, 0);
Assert.LessOrEqual(humidity, 100);
// Start measurement, Relative Humidity - hold master - 8-bit resolution
// Set 11-bit resolution
packet.Add((byte)0xFD);
packet.Add((byte)0xE6);
packet.Add((byte)0xBB);
sht21.Write(packet.ToArray());
packet.Clear();
// Start measurement
packet.Add((byte)0xFD);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
// Read Relative Humidity sensor data result
packet.Add((byte)0xFC);
packet.Add((byte)0xE5);
sht21.Write(packet.ToArray());
packet.Clear();
humidityBytes = sht21.Read();
// Check SHT21 CRC
resultArray = new byte[2] {
0, 0
};
resultArray[0] = humidityBytes[0];
resultArray[1] = humidityBytes[1];
checkCRC = GetSTH21CRC(resultArray, 2);
Assert.AreEqual(checkCRC, humidityBytes[2]);
// Assemble data bytes - precision value is 11 bit
humidityInt = (UInt32)((((UInt16)humidityBytes[0] << 3) & 0x7F8) + (((UInt16)humidityBytes[1] >> 5) & 0x7));
// Calculate relative humidity
// RH = -6 + 125 * SRH/2^16
humidity = 125.0 * Convert.ToDouble(humidityInt << 5) / 65536.0 - 6.0;
//humidity *= 100;
humidity = Math.Round(humidity, 1);
Assert.Greater(humidity, 0);
Assert.LessOrEqual(humidity, 100);
}
