.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.

.NET nanoFramework RAK4200 LoRaWAN library OTAA Join

When I first tried Over The Air Activation(OTAA) to connect to The Things Network(TTN) with my RAKwireless RAK4200 module it didn’t work. I built another test harness with an FTDI module so I could send AT commands with the RAK Serial Port Tool to my RAK4200 module.

RAK4200 -> FTDI -? PC test harness

The default baud rate is 115200 but I sent “at+set_config=device:uart:1:9600” to the RAK4200 module.

RAK Serial Port Tool initiating at+join command

With the RAK Serial Port Tool I could get the RAK4200 connected to TTN and send unconfirmed messages. The sequence of commands I used was

at+set_config=lora:join_mode:0
at+set_config=lora:class:0
at+set_config=lora:region:AS923
at+set_config=lora:dev_eui:XXXX
at+set_config=lora:app_eui:XXXX
at+set_config=lora:app_key:XXXX
at+set_config=device:restart
at+join
at+send=lora:2:48656c6c6f204c6f526157414e

I then returned to my STM32F769I Discovery, RAK4200 Breakoutboard, Seeedstudio Grove Base Shield for Arduino and a Seeedstudio Grove-4 pin Female Jumper to Grove 4 pin Conversion Cable based test harness.

RAK4200, STM32F769I Discovery test harness

I modified the NetworkJoinOTAA sample(based on the asynchronous version of BreakOutSerial) to send the same 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.Threading;

   public class Program
	{
      private const string SerialPortId = "COM6";
      private const string DevEui = "...";
      private const string AppEui = "...";
      private const string AppKey = "...";
      private const byte MessagePort = 1;
      private const string Payload = "48656c6c6f204c6f526157414e"; // Hello LoRaWAN

      public static void Main()
      {
         string response;

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

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

         try
         {
            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.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
               Console.WriteLine("lora:work_mode:0");
               serialDevice.WriteLine("at+set_config=lora:work_mode:0");

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

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

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

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

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

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

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

               // Reset the device
               Console.WriteLine("device:restart");
               serialDevice.WriteLine($"at+set_config=device:restart");
               Thread.Sleep(10000);

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

               while (true)
               {
                  // Send the BCD messages
                  Console.WriteLine("lora:{MessagePort}:{Payload}");
                  serialDevice.WriteLine($"at+send=lora:{MessagePort}:{Payload}");

                  Thread.Sleep(20000);
               }
            }
         }
         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 NetworkJoinOTAA application assumes that all of the AT commands succeed

Visual Studio Output windows displaying connection process and a D2C message
TTN Console live data tab connection process
TTN Console live messaging tab C2D message

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