.NET Core Seeed LoRaE5 LoRaWAN library Part1

Basic connectivity

Over the weekend I started building a .Net Core C# library for a Seeedstudio LoRa-E5 Development Kit which was connected to a Raspberry PI 3 with a Grove Base Hat for Raspberry Pi

The RaspberryPI OS is a bit more strict than the other devices I use about port access. To allow my .Net Core application to access a serial port I connected to the device with ExtraPutty, then ran the RaspberyPI configuration tool, from the command prompt with “sudo raspi-config”

RaspberyPI OS Software Configuration tool mains screen
RaspberryPI OS IO Serial Port configuration
Raspberry PI OS disabling remote serial login shell
RaspberryPI OS enabling serial port access

Once serial port access was enabled I could enumerate them with SerialPort.GetPortNames() which is in the System.IO.Ports NuGet package. The code has compile time options for synchronous and asynchronous operation.

//---------------------------------------------------------------------------------
// Copyright (c) September 2021, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.NetCore.SeeedLoRaE5.ShieldSerial
{
	using System;
	using System.Diagnostics;
	using System.IO.Ports;
	using System.Threading;

	public class Program
	{
		private const string SerialPortId = "/dev/ttyS0";

		public static void Main()
		{
			SerialPort serialPort;

			Debug.WriteLine("devMobile.IoT.NetCore.SeeedLoRaE5.ShieldSerial starting");

			Debug.WriteLine(String.Join(",", SerialPort.GetPortNames()));

			try
			{
				serialPort = new SerialPort(SerialPortId);

				// set parameters
				serialPort.BaudRate = 9600;
				serialPort.Parity = Parity.None;
				serialPort.DataBits = 8;
				serialPort.StopBits = StopBits.One;
				serialPort.Handshake = Handshake.None;

				serialPort.ReadTimeout = 1000;

				serialPort.NewLine = "\r\n";

				serialPort.Open();

#if SERIAL_ASYNC_READ
				serialPort.DataReceived += SerialDevice_DataReceived;
#endif

				while (true)
				{
					serialPort.WriteLine("AT+VER");

#if SERIAL_SYNC_READ
					string response = serialPort.ReadLine();

					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
#endif

					Thread.Sleep(20000);
				}
			}
			catch (Exception ex)
			{
				Debug.WriteLine(ex.Message);
			}
		}

#if SERIAL_ASYNC_READ
		private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
		{
			SerialPort serialPort = (SerialPort)sender;

			switch (e.EventType)
			{
				case SerialData.Chars:
					string response = serialPort.ReadExisting();

					Debug.WriteLine($"RX:{response.Trim()} bytes:{response.Length}");
					break;

				case SerialData.Eof:
					Debug.WriteLine("RX :EoF");
					break;
				default:
					Debug.Assert(false, $"e.EventType {e.EventType} unknown");
					break;
			}
		}
#endif
	}
}

The synchronous version of the test client requests the Seeeduino LoRa-E5 version information with the AT+VER command.

Synchronously reading characters from the Seeeduino LoRa-E5

The asynchronous version of the application displays character(s) as they arrive so a response can be split across multiple SerialDataReceived events.

Asynchronous versions displaying partial responses

I use the excellent RaspberryDebugger to download the application and debug it on my Raspberry PI 3.

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