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GSS2.Core/Hardware/TemperatureHumidityService.cs

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+using System.Device.I2c;
+using Microsoft.Extensions.Logging;
+
+namespace GSS2.Core.Hardware;
+
+public class TemperatureHumidityService : IDisposable
+{
+    public class TemperatureHumidityServiceConfiguration
+    {
+        public static TemperatureHumidityServiceConfiguration Default => new TemperatureHumidityServiceConfiguration
+        {
+            Bus = 0,
+            Address = 0x44
+        };
+
+        public int Bus { get; set; }
+        public int Address { get; set; }
+    }
+    private bool _disposedValue;
+    private readonly ILogger<TemperatureHumidityService> _logger;
+    private readonly TemperatureHumidityServiceConfiguration _configuration;
+
+    private readonly I2cDevice _sensor;
+
+    public TemperatureHumidityService(ILogger<TemperatureHumidityService> logger, TemperatureHumidityServiceConfiguration? configuration = null)
+    {
+        _logger = logger;
+
+        _logger.LogInformation("Temperature and humidity sensor initialization");
+
+        if (configuration is null)
+        {
+            _logger.LogWarning("Temperature and humidity sensor configuration not set. Using default configuration.");
+            _configuration = TemperatureHumidityServiceConfiguration.Default;
+        }
+        else
+        {
+            _configuration = configuration;
+        }
+
+        _logger.LogDebug(@$"Temperature and humidity sensor use following configuration:
+            Bus:     {_configuration.Bus}
+            Address: {_configuration.Address}
+        ");
+
+        try
+        {
+            _sensor = I2cDevice.Create(new I2cConnectionSettings(_configuration.Bus, _configuration.Address));
+        }
+        catch (Exception e)
+        {
+            _logger.LogCritical(e, "An exception occurred while temperature and humidity sensor initialization");
+            throw;
+        }
+    }
+
+    public async Task<(double temperature, double relativeHumidity)> MeasureAsync(int measurementsCount = 1, CancellationToken cancellationToken = default)
+    {
+        // В соответствии с даташитом на SHT45-AD1B-R2 псевдокод измерения с высокой точностью следующий:
+        // i2c_write(i2c_addr=0x44, tx_bytes=[0xFD])
+        // wait_seconds(0.01)
+        // rx_bytes = i2c_read(i2c_addr=0x44, number_of_bytes=6)
+        // t_ticks = rx_bytes[0] * 256 + rx_bytes[1]
+        // checksum_t = rx_bytes[2]
+        // rh_ticks = rx_bytes[3] * 256 + rx_bytes[4]
+        // checksum_rh = rx_bytes[5]
+        // t_degC = -45 + 175 * t_ticks/65535
+        // rh_pRH = -6 + 125 * rh_ticks/65535
+        // if (rh_pRH > 100):
+        // rh_pRH = 100
+        // if (rh_pRH < 0):
+        // rh_pRH = 0
+
+        if (measurementsCount <= 0)
+            throw new ArgumentOutOfRangeException(nameof(measurementsCount));
+
+        double sumTemperature = 0;
+        double sumRelativeHumidity = 0;
+        int successMeasurementsCount = 0;
+
+        Span<byte> command = stackalloc byte[] { 0xFD };
+        Span<byte> data = stackalloc byte[6];
+
+        for (int i = 0; i < measurementsCount; i++)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+
+            try
+            {
+                // Отправляем команду
+                _sensor.Write(command);
+                // 10 мс ожидания
+                await Task.Delay(10, cancellationToken);
+                // Читаем данные
+                _sensor.Read(data);
+
+                // Распаковываем данные [2 * 8-bit T-data; 8-bit CRC; 2 * 8-bit RH-data; 8-bit CRC]
+                ushort temperatureTicks = BitConverter.ToUInt16(data.ToArray(), 0);
+                byte temperatureChecksum = data[2];
+                int relativeHumidityTicks = BitConverter.ToUInt16(data.ToArray(), 3);
+                byte relativeHumidityChecksum = data[5];
+
+                // Проверка по CRC
+                if (!CheckCrc(data.Slice(0, 2), temperatureChecksum) ||
+                    !CheckCrc(data.Slice(3, 2), relativeHumidityChecksum))
+                {
+                    _logger.LogWarning("Temperature and humidity sensor CRC error");
+                    continue;
+                }
+
+                // Пересчёт
+                double temperature = -45 + 175 * (temperatureTicks / 65535.0);
+                double relativeHumidity = -6 + 125 * (relativeHumidityTicks / 65535.0);
+                relativeHumidity = Math.Clamp(relativeHumidity, 0, 100);
+
+                // Сумма для усреднения
+                sumTemperature += temperature;
+                sumRelativeHumidity += relativeHumidity;
+                successMeasurementsCount++;
+            }
+            catch (Exception e)
+            {
+                _logger.LogWarning(e, "Temperature and humidity sensor not available on I2C bus");
+            }
+        }
+
+        if (successMeasurementsCount == 0)
+        {
+            _logger.LogError("Temperature and humidity sensor: no successful measurements");
+            return (double.NaN, double.NaN);
+        }
+
+        return (sumTemperature / successMeasurementsCount, sumRelativeHumidity / successMeasurementsCount);
+    }
+
+    private static bool CheckCrc(Span<byte> data, byte expectedCrc)
+    {
+        byte crc = 0xFF;
+        foreach (var b in data)
+        {
+            crc ^= b;
+            for (int i = 0; i < 8; i++)
+            {
+                if ((crc & 0x80) != 0)
+                    crc = (byte)((crc << 1) ^ 0x31);
+                else
+                    crc <<= 1;
+            }
+        }
+        return crc == expectedCrc;
+    }
+
+    protected virtual void Dispose(bool disposing)
+    {
+        if (!_disposedValue)
+        {
+            if (disposing)
+            {
+                try
+                {
+                    _sensor?.Dispose();
+                }
+                catch { }
+            }
+
+            _disposedValue = true;
+        }
+    }
+    void IDisposable.Dispose()
+    {
+        Dispose(disposing: true);
+        GC.SuppressFinalize(this);
+    }
+}