.NET nanoFramework RAK4200 LoRaWAN library ABP Join

After getting my RAKwireless RAK4200 module to reliably connect to The Things Network(TTN) using Over The Air Activation(OTAA) the next step was to built an Activation By Personalisation(ABP) sample application.

I modified the NetworkJoinOTAA sample(based on the asynchronous version of BreakOutSerial) to send the required sequence of AT commands and display the responses.

namespace devMobile.IoT.LoRaWAN.nanoFramework.RAK4200
{
   using System;
   using System.Diagnostics;
   using System.IO.Ports;
   using System.Text;
   using System.Threading;
#if ESP32_WROOM
   using global::nanoFramework.Hardware.Esp32; ///need NuGet nanoFramework.Hardware.Esp32
#endif

   public class Program
   {
#if ST_STM32F769I_DISCOVERY
      private const string SerialPortId = "COM6";
#endif
#if ESP32_WROOM
      private const string SerialPortId = "COM2";
#endif
      private const string DevEui = "...";
      private const string AppEui = "...";
      private const string AppKey = "...";
      private const byte MessagePort = 1;
      private const string Payload = "01020304"; // Is AQIDBA==

      public static void Main()
      {
         string response;

         Debug.WriteLine("devMobile.IoT.Rak4200.NetworkJoinOTAA starting");

         try
         {
#if ESP32_WROOM
            Configuration.SetPinFunction(Gpio.IO16, DeviceFunction.COM2_TX);
            Configuration.SetPinFunction(Gpio.IO17, DeviceFunction.COM2_RX);
#endif

            Debug.Write("Ports:");
            foreach (string port in SerialPort.GetPortNames())
            {
               Debug.Write($" {port}");
            }
            Debug.WriteLine("");

            using (SerialPort serialDevice = new SerialPort(SerialPortId))
            {
               // set parameters
               serialDevice.BaudRate = 9600;
               //_SerialPort.BaudRate = 115200;
               serialDevice.Parity = Parity.None;
               serialDevice.StopBits = StopBits.One;
               serialDevice.Handshake = Handshake.None;
               serialDevice.DataBits = 8;

               serialDevice.ReadTimeout = 10000;
               //serialDevice.ReadBufferSize = 128; 
               //serialDevice.ReadBufferSize = 256; 
               serialDevice.ReadBufferSize = 512;
               //serialDevice.ReadBufferSize = 1024;

               serialDevice.NewLine = "\r\n";

               serialDevice.DataReceived += SerialDevice_DataReceived;

               serialDevice.Open();

               serialDevice.WatchChar = '\n';

               // clear out the RX buffer
               serialDevice.ReadExisting();
               response = serialDevice.ReadExisting();
               Debug.WriteLine($"Response :{response.Trim()} bytes:{response.Length}");
               Thread.Sleep(500);

               // Set the Working mode to LoRaWAN
               Debug.WriteLine("lora:work_mode:0");
               serialDevice.WriteLine("at+set_config=lora:work_mode:0");
               Thread.Sleep(1500);

               // Set the JoinMode
               Debug.WriteLine("lora:join_mode");
               serialDevice.WriteLine("at+set_config=lora:join_mode:0");
               Thread.Sleep(500);

               // Set the Class
               Debug.WriteLine("lora:class");
               serialDevice.WriteLine("at+set_config=lora:class:0");
               Thread.Sleep(500);

               // Set the Region to AS923
               Debug.WriteLine("lora:region");
               serialDevice.WriteLine("at+set_config=lora:region:AS923");
               Thread.Sleep(500);

               // Set the devEUI
               Debug.WriteLine("lora:dev_eui");
               serialDevice.WriteLine($"at+set_config=lora:dev_eui:{DevEui}");
               Thread.Sleep(500);

               // Set the appEUI
               Debug.WriteLine("lora:app_eui");
               serialDevice.WriteLine($"at+set_config=lora:app_eui:{AppEui}");
               Thread.Sleep(500);

               // Set the appKey
               Debug.WriteLine("lora:app_key");
               serialDevice.WriteLine($"at+set_config=lora:app_key:{AppKey}");
               Thread.Sleep(500);

               // Set the Confirm flag
               Debug.WriteLine("lora:confirm");
               serialDevice.WriteLine("at+set_config=lora:confirm:0");
               Thread.Sleep(500);

               Debug.WriteLine("lora:adr");
               serialDevice.WriteLine("at+set_config=lora:adr:1");
               Thread.Sleep(500);

               // Join the network
               Debug.WriteLine("at+join");
               serialDevice.WriteLine("at+join");
               Thread.Sleep(10000);

               byte counter = 1;
               while (true)
               {
                  // Send the BCD messages
                  string payload = $"{Payload}{counter:X2}";
                  Debug.WriteLine($"at+send=lora:{MessagePort}:{payload}");
                  serialDevice.WriteLine($"at+send=lora:{MessagePort}:{payload}");

                  counter += 1;

                  Thread.Sleep(300000);
               }
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);
         }
      }

      private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
      {
         SerialPort serialPort = (SerialPort)sender;
         string response;

         switch (e.EventType)
         {
            case SerialData.Chars:
               break;

            case SerialData.WatchChar:
               response = serialPort.ReadExisting();
               Debug.Write(response);
               break;
            default:
               Debug.Assert(false, $"e.EventType {e.EventType} unknown");
               break;
         }
      }
   }
}

The NetworkJoinABP application assumes that all of the AT commands succeed.

TTN Console live data tab connection process
Visual Studio Output windows displaying connection process and a D2C message

I have been using at+set_config=lora:default_parameters set the WisDuo RAK4200 back to factory settings so I can figure out what settings are persisted by a “at+set_config=device:restart” and which ones need to be set every time the application is run.

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