public class Program
{
   // === Sensor Modbus params (from Seeed datasheet and label on cable) ===
   const byte SlaveAddress = 0x2A;   // default
   const ushort RegTemperature = 0x00; // int16 (twos-comp), value = °C * 100
   const ushort RegHumidity = 0x01; // uint16, value = %RH * 100
   const ushort RegDewPointTemperature = 0x02; // int16 (twos-comp), value = °C * 100

   public static void Main()
   {
      Console.WriteLine("Modbus Client for Seeedstudio Temperature Humidity and Dew point sensor SKU101990882");

#if ESP32_XIAO_ESP32_S3
      Configuration.SetPinFunction(Gpio.IO06, DeviceFunction.COM2_RX);
      Configuration.SetPinFunction(Gpio.IO05, DeviceFunction.COM2_TX);
      Configuration.SetPinFunction(Gpio.IO03, DeviceFunction.COM2_RTS);
#endif 
      var ports = SerialPort.GetPortNames();

      Console.WriteLine("Available ports: ");
      foreach (string port in ports)
      {
         Console.WriteLine($" {port}");
      }

      // Modbus Client
      using (var _client = new ModbusClient("COM2"))
      {
#if DEBUG_LOGGER
         _client.Logger = new DebugLogger("ModbusClient") 
         { 
            MinLogLevel = LogLevel.Debug 
         };
#endif

         while (true)
         {
            try
            {
               // regs[0] = Temperature.
               var regs = _client.ReadHoldingRegisters(SlaveAddress, RegTemperature, 3);
               short rawTemperature = regs[RegTemperature];
               double temperature = rawTemperature / 100.0; // Signed 16 - bit, value = °C * 100

               // regs[1] = Humidity.
               ushort rawRelativeHumidity = unchecked((ushort)regs[RegHumidity]);
               double relativeHumidity = rawRelativeHumidity / 100.0; // Humidity. Unsigned 16-bit, value = %RH * 100

               // regs[2] = Dewpoint.
               short rawDewPointTemperature = regs[RegDewPointTemperature];
               double dewPointTemperature = rawDewPointTemperature / 100.0; // Signed 16 - bit, value = °C * 100

               Console.WriteLine($"Temperature: {temperature:F1}°C, RH: {relativeHumidity:F0}%, Dewpoint:{dewPointTemperature:F1} °C");
            }
            catch (Exception ex)
            {
               Console.WriteLine($"Read failed: {ex.Message}");
            }

            Thread.Sleep(60000);
         }
      }
   }
}