nanoFramework RAK811 LoRaWAN library Part7

Now with added callbacks

After building a nanoFramwork library “inspired” by the RakWireless Arduino library(which has some issues) I figured it would be good to refactor the library to be more asynchronous with event handlers for send confirmation (if configured) and received messages.

If the RAK811 module is initialised, and connects to the network successfully, the application sends “48656c6c6f204c6f526157414e” (“hello LoRaWAN”) every 5 minutes.

STM32F691Discovery with EVB plugged into Arduino headers

The code application code now has a lot more compile time options for network configuration and payload format.

//---------------------------------------------------------------------------------
// Copyright (c) June 2020, 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.
//
//---------------------------------------------------------------------------------
#define ST_STM32F769I_DISCOVERY      // nanoff --target ST_STM32F769I_DISCOVERY --update 
#define PAYLOAD_BCD
//#define PAYLOAD_BYTES
#define OTAA
//#define ABP
#define CONFIRMED
namespace devMobile.IoT.Rak811LoRaWanDeviceClient
{
   using System;
   using System.Threading;
   using System.Diagnostics;
   using Windows.Devices.SerialCommunication;

   using devMobile.IoT.LoRaWan;

   public class Program
   {
#if ST_STM32F769I_DISCOVERY
      private const string SerialPortId = "COM6";
#endif
#if OTAA
      private const string DevEui = "...";
      private const string AppEui = "...";
      private const string AppKey = "...";
#endif
#if ABP
      private const string DevAddress = "...";
      private const string NwksKey = "...";
      private const string AppsKey = "...";
#endif
      private const string Region = "AS923";
      private static readonly TimeSpan JoinTimeOut = new TimeSpan(0, 0, 10);
      private static readonly TimeSpan SendTimeout = new TimeSpan(0, 0, 10);
      private const byte MessagePort = 1;
#if PAYLOAD_BCD
      private const string PayloadBcd = "48656c6c6f204c6f526157414e"; // Hello LoRaWAN in BCD
#endif
#if PAYLOAD_BYTES
      private static readonly byte[] PayloadBytes = { 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x4c, 0x6f, 0x52, 0x61, 0x57, 0x41, 0x4e}; // Hello LoRaWAN in bytes
#endif

      public static void Main()
      {
         Result result;

         Debug.WriteLine("devMobile.IoT.Rak811LoRaWanDeviceClient starting");

         Debug.WriteLine($"Ports :{Windows.Devices.SerialCommunication.SerialDevice.GetDeviceSelector()}");

         try
         {
            using ( Rak811LoRaWanDevice device = new Rak811LoRaWanDevice())
            {
               result = device.Initialise(SerialPortId, 9600, SerialParity.None, 8, SerialStopBitCount.One);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Initialise failed {result}");
                  return;
               }

#if CONFIRMED
               device.OnMessageConfirmation += OnMessageConfirmationHandler;
#endif
               device.OnReceiveMessage += OnReceiveMessageHandler;

               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Region {Region}");
               result = device.Region(Region);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Region failed {result}");
                  return;
               }

               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} ADR On");
               result = device.AdrOn();
               if (result != Result.Success)
               {
                  Debug.WriteLine($"ADR on failed {result}");
                  return;
               }

#if CONFIRMED
               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Confirmed");
               result = device.Confirm(LoRaConfirmType.Confirmed);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Confirm on failed {result}");
                  return;
               }
#else
               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Unconfirmed");
               result = device.Confirm(LoRaConfirmType.Unconfirmed);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Confirm off failed {result}");
                  return;
               }
#endif

#if OTAA
               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} OTAA");
               result = device.OtaaInitialise(DevEui, AppEui, AppKey);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"OTAA Initialise failed {result}");
                  return;
               }
#endif

#if ABP
               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} ABP");
               result = device.AbpInitialise(DevAddress, NwksKey, AppsKey);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"ABP Initialise failed {result}");
                  return;
               }
#endif

               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Join start Timeout:{JoinTimeOut:hh:mm:ss}");
               result = device.Join(JoinTimeOut);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Join failed {result}");
                  return;
               }
               Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Join finish");

               while (true)
               {
#if PAYLOAD_BCD
                  Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Send Timeout:{SendTimeout:hh:mm:ss} port:{MessagePort} payload BCD:{PayloadBcd}");
                  result = device.Send(MessagePort, PayloadBcd, SendTimeout);
#endif
#if PAYLOAD_BYTES
                  Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Send Timeout:{SendTimeout:hh:mm:ss} port:{MessagePort} payload Bytes:{BitConverter.ToString(PayloadBytes)}");
                  result = device.Send(MessagePort, PayloadBytes, SendTimeout);
#endif
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Send failed {result}");
                  }

                  // if we sleep module too soon response is missed
                  Thread.Sleep(new TimeSpan( 0,0,5));

                  Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Sleep");
                  result = device.Sleep();
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Sleep failed {result}");
                     return;
                  }

                  Thread.Sleep(new TimeSpan(0, 5, 0));

                  Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Wakeup");
                  result = device.Wakeup();
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Wakeup failed {result}");
                     return;
                  }
               }
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);
         }
      }

      static void OnMessageConfirmationHandler(int rssi, int snr)
      {
         Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Send Confirm RSSI:{rssi} SNR:{snr}");
      }

      static void OnReceiveMessageHandler(int port, int rssi, int snr, string payloadBcd)
      {
         byte[] payloadBytes = Rak811LoRaWanDevice.BcdToByes(payloadBcd);

         Debug.WriteLine($"{DateTime.UtcNow:hh:mm:ss} Receive Message RSSI:{rssi} SNR:{snr} Port:{port} Payload:{payloadBcd} PayLoadBytes:{BitConverter.ToString(payloadBytes)}");
      }
   }
}

The debugging output with the Rak811LoRaWanDevice class diagnostics off

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.IoT.Rak811LoRaWanDeviceClient starting
Ports :COM5,COM6
12:00:51 Region AS923
12:00:51 ADR On
12:00:51 Confirmed
12:00:52 OTAA
12:00:52 Join start Timeout:00:00:10
12:00:59 Join finish
12:00:59 Send Timeout:00:00:10 port:1 payload BCD:48656c6c6f204c6f526157414e
12:01:02 Send Confirm RSSI:-79 SNR:9
12:01:07 Sleep
12:06:07 Wakeup
12:06:07 Send Timeout:00:00:10 port:1 payload BCD:48656c6c6f204c6f526157414e
12:06:08 Send Confirm RSSI:-65 SNR:8
12:06:13 Sleep
12:11:13 Wakeup
12:11:13 Send Timeout:00:00:10 port:1 payload BCD:48656c6c6f204c6f526157414e
12:11:15 Send Confirm RSSI:-60 SNR:7
12:11:15 Receive Message RSSI:-60 SNR:7 Port:5 Payload:48656c6c6f PayLoadBytes:48-65-6C-6C-6F
12:11:20 Sleep
TTN OTAA Connection + RX&TX

Some commands are quite quick to respond e.g. setting the Region, Sleep, and Wakeup. Others, take quite a while e.g. Join, Send, WorkMode so they have separate timeout configurations.

The code is approaching beat and I’ll be testing and fixing bugs for the next couple of days.

nanoFramework RAK811 LoRaWAN library Part6

Inspired by the Arduino Library

After successful proof of concept projects I have build a nanoFramwork library “inspired” by the RakWireless Arduino library.

The initial version only supports my RAK811 LPWAN Evaluation Board(EVB) and STM32F691DISCOVERY based test rig It handles failures, displays error codes/messages, but doesn’t handle all timeouts.

If the RAK811 module is initialised, then connects to the network successfully, the application sends “48656c6c6f204c6f526157414e” (“hello LoRaWAN”) every 20 seconds.

STM32F691Discovery with EVB plugged into Arduino headers

The code application code is now a lot smaller & simpler

   public class Program
   {
#if ST_STM32F769I_DISCOVERY
      private const string SerialPortId = "COM6";
#endif
#if OTAA
      private const string DevEui = "...";
      private const string AppEui = "...";
      private const string AppKey = "...";
#endif
#if ABP
      private const string devAddress = "...";
      private const string nwksKey = "...";
      private const string appsKey = "...";
#endif
      private const byte MessagePort = 1;
      private const string Payload = "48656c6c6f204c6f526157414e"; // Hello LoRaWAN

      public static void Main()
      {
         Result result;

         Debug.WriteLine(" devMobile.IoT.Rak811LoRaWanDeviceClient starting");

         Debug.WriteLine(Windows.Devices.SerialCommunication.SerialDevice.GetDeviceSelector());

         try
         {
            using ( Rak811LoRaWanDevice device = new Rak811LoRaWanDevice())
            {
               result = device.Initialise(SerialPortId, SerialParity.None, 8, SerialStopBitCount.One);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Initialise failed {result}");
                  return;
               }

               result = device.Region("AS923");
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Region failed {result}");
                  return;
               }

#if OTAA
               result = device.OtaaInitialise(DevEui, AppEui, AppKey);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"OTAA Initialise failed {result}");
                  return;
               }
#endif

#if ABP
               result = device.AbpInitialise(devAddress, nwksKey, appsKey);
               if (result != Result.Success)
               {
                  Debug.WriteLine($"ABP Initialise failed {result}");
                  return;
               }
#endif

               result = device.Join(new TimeSpan(0,0,10));
               if (result != Result.Success)
               {
                  Debug.WriteLine($"Join failed {result}");
                  return;
               }

               while (true)
               {
                  result = device.Send(MessagePort, Payload);
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Send failed {result}");
                  }

                  result = device.Sleep();
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Sleep failed {result}");
                     return;
                  }

                  Thread.Sleep(20000);

                  result = device.Wakeup();
                  if (result != Result.Success)
                  {
                     Debug.WriteLine($"Wakeup failed {result}");
                     return;
                  }
               }
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);
         }
      }
   }

I compared the debugging output with confirmations off

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
 devMobile.IoT.Rak811LoRaWanDeviceClient starting
COM5,COM6
01:11:13 lora:work_mode
TX: send 32 bytes 32 via COM6
RX 01:11:14:UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:OTAA, Class: A
Initialization OK 

01:11:15 lora:region
TX: send 33 bytes 33 via COM6
RX 01:11:16:OK 

01:11:16 lora:join_mode
TX: send 32 bytes 32 via COM6
RX 01:11:17:OK 

01:11:18 lora:dev_eui
TX: send 45 bytes 45 via COM6
RX 01:11:19:OK 

01:11:19 lora:app_eui
TX: send 45 bytes 45 via COM6
RX 01:11:20:OK 

01:11:21 lora:app_key
TX: send 61 bytes 61 via COM6
RX 01:11:22:OK 

01:11:22 join
TX: send 9 bytes 9 via COM6
RX 01:11:29:OK Join Success

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK 

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK 
at+recv=1,-54,9,5:48656c6c6f

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK 
at+recv=2,-51,7,5:48656c6c6f

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6

Then with confirmations on (note the at+recv=0,-59,7,0) and received messages (at+recv=23,-53,8,5:48656c6c6f)

devMobile.IoT.Rak811LoRaWanDeviceClient starting
COM5,COM6
01:20:54 lora:work_mode
TX: send 32 bytes 32 via COM6
RX 01:20:56:UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:OTAA, Class: A
Initialization OK 

01:20:56 lora:region
TX: send 33 bytes 33 via COM6
RX 01:20:57:OK 

01:20:58 lora:join_mode
TX: send 32 bytes 32 via COM6
RX 01:20:59:OK 

01:20:59 lora:dev_eui
TX: send 45 bytes 45 via COM6
RX 01:21:00:OK 

01:21:01 lora:app_eui
TX: send 45 bytes 45 via COM6
RX 01:21:02:OK 

01:21:02 lora:app_key
TX: send 61 bytes 61 via COM6
RX 01:21:03:OK 

01:21:04 join
TX: send 9 bytes 9 via COM6
RX 01:21:11:OK Join Success

01:21:11 lora:confirm
TX: send 30 bytes 30 via COM6
RX 01:21:12:OK 

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK 
at+recv=23,-53,8,5:48656c6c6f

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK 
at+recv=0,-59,7,0

In the Visual Studio 2019 debug output I could see the responses to the AT Commands and especially the lack of handling of downlink messages and confirmations from the network.

The next step is to implement timeouts for when operations fail or the module doesn’t respond. Then extend the code to support the receiving of messages as a class A device (missing for the RAK arduino library). I wonder how this will work for when the module is configured as a class C device which can receive messages at any time.

Some commands are quite quick to respond e.g. setting the Region, Sleep, and Wakeup so are most probably ok running synchronously. Other commands can take quite a while e.g. Join, Send, WorkMode so maybe these need to be asynchronous (along with the receiving of confirmations and messages ).

The code is not suitable for production but it confirmed my new approach worked.

nanoFramework RAK811 LoRaWAN library Part5

Nasty ABP connect

After a successful Over The Air Activation(OTAA) with my RAK811 LPWAN Evaluation Board(EVB) and STM32F691DISCOVERY based test rig. I figured for completeness an Activation by Personalization (ABP) would be a good.

My ABP implementation is based on my OTAA one so is pretty “nasty”. Again, I assumed that there would be no timeouts or failures and I only send one message BCD “48656c6c6f204c6f526157414e” (“hello LoRaWAN”) every 20 seconds.

STM32F691Discovery with EVB plugged into Arduino headers

I created a new ABP device

Things Network ABP configuration

Then I configured the RAK811 module for LoRaWAN

// Set the Working mode to LoRaWAN
bytesWritten = outputDataWriter.WriteString("at+set_config=lora:work_mode:0rn");
Debug.WriteLine($"TX: work_mode {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   string response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX sync:{response}");
}

Then sequentially stepped through the necessary configuration to join the The Things Network(TTN) network

// Set the JoinMode to ABP
bytesWritten = outputDataWriter.WriteString($"at+set_config=lora:join_mode:1\r\n");
Debug.WriteLine($"TX: join_mode {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   String response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX :{response}");
}

// Set the device address
bytesWritten = outputDataWriter.WriteString($"at+set_config=lora:dev_addr:{devAddress}\r\n");
Debug.WriteLine($"TX: dev_addr {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
   {
   String response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX :{response}");
   }
...

After making a few fixes to my code and tweaking some settings I could see data in the TTN Console.

ABP Device data uplink

The code is not suitable for production but it confirmed my software and hardware configuration worked.

In the Visual Studio 2019 debug output I could see the AT Command responses from were getting truncated in odd ways so I need to be careful how they are processed.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.IoT.Rak811.NetworkJoinABP starting
COM5,COM6
TX: work_mode 32 bytes to output stream.
TX: 32 bytes via COM6
RX :UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:ABP, Class: A
Initialization OK 

TX: region 33 bytes to output stream.
TX: 33 bytes via COM6
RX :OK 

TX: join_mode 32 bytes to output stream.
TX: 32 bytes via COM6
RX :OK 

TX: dev_addr 38 bytes to output stream.
TX: 38 bytes via COM6
RX :OK 

TX: nwks_key 62 bytes to output stream.
TX: 62 bytes via COM6
RX :OK 

TX: apps_key 62 bytes to output stream.
TX: 62 bytes via COM6
RX :OK 

TX: confirm 30 bytes to output stream.
TX: 30 bytes via COM6
RX :OK 

TX: join 9 bytes to output stream.
TX: 9 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :OK Jo
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :in Su
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :ccess
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :
OK 
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX :
OK 

The next step is to get rework the code to process responses to the AT commands in a smarter way and extract error codes when an operation fails.

nanoFramework RAK811 LoRaWAN library Part4

Nasty OTAA connect

After getting basic connectivity for my RAK811 LPWAN Evaluation Board(EVB) and STM32F691DISCOVERY test rig sorted. I wanted to see if I could get the device connected to The Things Network(TTN) via the RAK7246G LPWAN Developer Gateway which was on my desk. I had got the EVB configuration sorted with an Arduino Uno R3 device so I was confident it should work.

STM32F691Discovery with EVB plugged into Arduino headers

My Over the Air Activation(OTAA) implementation is pretty “nasty” I assumed that there would be no timeouts or failures and I only send one BCD message “48656c6c6f204c6f526157414e” which is “hello LoRaWAN”

I configured the RAK811 module for LoRaWAN

// Set the Working mode to LoRaWAN
bytesWritten = outputDataWriter.WriteString("at+set_config=lora:work_mode:0\r\n");
Debug.WriteLine($"TX: work_mode {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   string response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX sync:{response}");
}

Then just sequentially stepped through the necessary configuration to join the TTN network

// Set the Region to AS923
bytesWritten = outputDataWriter.WriteString("at+set_config=lora:region:AS923\r\n");
Debug.WriteLine($"TX: region {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   String response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX sync:{response}");
}

// Set the JoinMode
bytesWritten = outputDataWriter.WriteString($"at+set_config=lora:join_mode:0\r\n");
Debug.WriteLine($"TX: join_mode {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   String response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX sync:{response}");
}

// OTAA set the devEUI
bytesWritten = outputDataWriter.WriteString($"at+set_config=lora:dev_eui:{devEui}\r\n");
Debug.WriteLine($"TX: dev_eui {outputDataWriter.UnstoredBufferLength} bytes to output stream.");
txByteCount = outputDataWriter.Store();
Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

// Read the response
bytesRead = inputDataReader.Load(128);
if (bytesRead > 0)
{
   String response = inputDataReader.ReadString(bytesRead);
   Debug.WriteLine($"RX sync:{response}");
}
...

The code is not suitable for production but it confirmed my software and hardware configuration worked.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.IoT.Rak811.NetworkJoinOTAA starting
COM5,COM6
TX: work_mode 32 bytes to output stream.
TX: 32 bytes via COM6
RX sync:UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:OTAA, Class: A
Initialization OK 

TX: region 33 bytes to output stream.
TX: 33 bytes via COM6
RX sync:OK 

TX: join_mode 32 bytes to output stream.
TX: 32 bytes via COM6
RX sync:OK 

TX: dev_eui 45 bytes to output stream.
TX: 45 bytes via COM6
RX sync:OK 

TX: app_eui 45 bytes to output stream.
TX: 45 bytes via COM6
RX sync:OK 

TX: app_key 61 bytes to output stream.
TX: 61 bytes via COM6
RX sync:OK 

TX: confirm 30 bytes to output stream.
TX: 30 bytes via COM6
RX sync:OK 

TX: join 9 bytes to output stream.
TX: 9 bytes via COM6
RX sync:
RX sync:
RX sync:
RX sync:
RX sync:OK Join Success

TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
TX: send 43 bytes to output stream.
TX: 43 bytes via COM6
RX sync:OK 
at+recv=0,-59,9,0

In the Visual Studio 2019 debug out put I could see messages getting sent and then after a short delay they were visible in the TTN console.

I then modified the confirmed flag and in the TTN console I could see how they were processed differently.

Confirmed messages
Unconfirmed messages

I could receive messages but as the RAK 811 module can be configured to be a Class C device there didn’t appear to be a way to receive a message without sending one which seemed a bit odd.

The next step is to get Authentication By Personalisation(ABP) working.

nanoFramework RAK811 LoRaWAN library Part3

Factory Reset

When writing communications libraries one of the first things I try and get working is a “factory reset”. At some stage I will misconfigure the device so badly that it won’t work anymore and having a way to return to the device to its original configuration is really useful.

The RAK811 LPWAN Evaluation Board(EVB) test rig was based on an STM32F691DISCOVERY board which supports hardware (using D8 as I haven’t removed R11) and software reset with an AT command.

//---------------------------------------------------------------------------------
// Copyright (c) June 2020, 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.
//
//---------------------------------------------------------------------------------
// nanoff --target ST_STM32F769I_DISCOVERY --update
//#define SERIAL_SYNC_READ
//#define HARDWARE_RESET
//#define SOFTWARE_RESTART
//#define DEVICE_STATUS
//#define LORA_STATUS
namespace devMobile.IoT.Rak811.FactoryReset
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using Windows.Devices.Gpio;
   using Windows.Devices.SerialCommunication;
   using Windows.Storage.Streams;
   
   public class Program
   {
      private const string SerialPortId = "COM6";

      public static void Main()
      {
         SerialDevice serialDevice;

         Debug.WriteLine("devMobile.IoT.Rak811.FactoryReset starting");

         Debug.WriteLine(Windows.Devices.SerialCommunication.SerialDevice.GetDeviceSelector());

         try
         {
#if HARDWARE_RESET
            GpioPin resetPin = GpioController.GetDefault().OpenPin(PinNumber('J', 4));
            resetPin.SetDriveMode(GpioPinDriveMode.Output);
            resetPin.Write(GpioPinValue.Low);
#endif
            serialDevice = SerialDevice.FromId(SerialPortId);

            // set parameters
            serialDevice.BaudRate = 9600;
            serialDevice.Parity = SerialParity.None;
            serialDevice.StopBits = SerialStopBitCount.One;
            serialDevice.Handshake = SerialHandshake.None;
            serialDevice.DataBits = 8;

            serialDevice.ReadTimeout = new TimeSpan(0, 0, 30);
            serialDevice.WriteTimeout = new TimeSpan(0, 0, 4);

            DataWriter outputDataWriter = new DataWriter(serialDevice.OutputStream);

#if SERIAL_SYNC_READ
            DataReader inputDataReader = new DataReader(serialDevice.InputStream);
#else
            serialDevice.DataReceived += SerialDevice_DataReceived;
#endif

            // set a watch char to be notified when it's available in the input stream
            serialDevice.WatchChar = '\n';

            while (true)
            {
#if HARDWARE_RESET
               resetPin.Write(GpioPinValue.High);
               Thread.Sleep(10);
               resetPin.Write(GpioPinValue.Low);
#endif

#if SOFTWARE_RESTART
               uint bytesWritten = outputDataWriter.WriteString("at+set_config=device:restart\r\n");
               Debug.WriteLine($"TX: {outputDataWriter.UnstoredBufferLength} bytes to output stream.");

               // calling the 'Store' method on the data writer actually sends the data
               uint txByteCount = outputDataWriter.Store();
               Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");
#endif

#if DEVICE_STATUS
               uint bytesWritten = outputDataWriter.WriteString("at+get_config=device:status\r\n");
               Debug.WriteLine($"TX: {outputDataWriter.UnstoredBufferLength} bytes to output stream.");

               // calling the 'Store' method on the data writer actually sends the data
               uint txByteCount = outputDataWriter.Store();
               Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");
#endif

#if LORA_STATUS
               uint bytesWritten = outputDataWriter.WriteString("at+get_config=lora:status\r\n");
               Debug.WriteLine($"TX: {outputDataWriter.UnstoredBufferLength} bytes to output stream.");

               // calling the 'Store' method on the data writer actually sends the data
               uint txByteCount = outputDataWriter.Store();
               Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");
#endif

#if SERIAL_SYNC_READ
               // June 2020 appears to be limited to 256 chars
               uint bytesRead = inputDataReader.Load(50);

               Debug.WriteLine($"RXs :{bytesRead} bytes read from {serialDevice.PortName}");

               if (bytesRead > 0)
               {
                  String response = inputDataReader.ReadString(bytesRead);
                  Debug.WriteLine($"RX sync:{response}");
               }
#endif

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

      private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
      {
         switch (e.EventType)
         {
            case SerialData.Chars:
               //Debug.WriteLine("RX SerialData.Chars");
               break;

            case SerialData.WatchChar:
               Debug.WriteLine("RX: SerialData.WatchChar");
               SerialDevice serialDevice = (SerialDevice)sender;

               using (DataReader inputDataReader = new DataReader(serialDevice.InputStream))
               {
                  inputDataReader.InputStreamOptions = InputStreamOptions.Partial;

                  // read all available bytes from the Serial Device input stream
                  uint bytesRead = inputDataReader.Load(serialDevice.BytesToRead);

                  Debug.WriteLine($"RXa: {bytesRead} bytes read from {serialDevice.PortName}");

                  if (bytesRead > 0)
                  {
                     String response = inputDataReader.ReadString(bytesRead);
                     Debug.WriteLine($"RX:{response}");
                  }
               }
               break;
            default:
               Debug.Assert(false, $"e.EventType {e.EventType} unknown");
               break;
         }
      }
      static int PinNumber(char port, byte pin)
      {
         if (port < 'A' || port > 'J')
            throw new ArgumentException();

         return ((port - 'A') * 16) + pin;
      }
   }
}

Initially I tried strobing D8 which is connected to the reset pin on the RAK811 module.

UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:OTAA, Class: A
Initialization OK 

I then used the RAK Serial Port Tool to see if the configuration had changed

OK Work Mode: LoRaWAN
Region: AS923
Send_interval: 600s
Auto send status: false.
Join_mode: OTAA
DevEui: ...
AppEui: ...
AppKey: ...
Class: A
Joined Network:false
IsConfirm: false
AdrEnable: true
EnableRepeaterSupport: false
RX2_CHANNEL_FREQUENCY: 923200000, RX2_CHANNEL_DR:2
RX_WINDOW_DURATION: 3000ms
RECEIVE_DELAY_1: 1000ms
RECEIVE_DELAY_2: 2000ms
JOIN_ACCEPT_DELAY_1: 5000ms
JOIN_ACCEPT_DELAY_2: 6000ms
Current Datarate: 2
Primeval Datarate: 2
ChannelsTxPower: 0
UpLinkCounter: 0
DownLinkCounter: 0

The device reset but the settings appear not to have returned to factory.

I then tried the device:restart AT command

>>at+set_config=device:restart
UART1 work mode: RUI_UART_NORAMAL
Current work_mode:LoRaWAN, join_mode:OTAA, Class: A
Initialization OK 

>>at+get_config=lora:status
OK Work Mode: LoRaWAN
Region: AS923
Send_interval: 600s
Auto send status: false.
Join_mode: OTAA
DevEui: ...
AppEui: ...
AppKey: ...
Class: A
Joined Network:false
IsConfirm: false
AdrEnable: true
EnableRepeaterSupport: false
RX2_CHANNEL_FREQUENCY: 923200000, RX2_CHANNEL_DR:2
RX_WINDOW_DURATION: 3000ms
RECEIVE_DELAY_1: 1000ms
RECEIVE_DELAY_2: 2000ms
JOIN_ACCEPT_DELAY_1: 5000ms
JOIN_ACCEPT_DELAY_2: 6000ms
Current Datarate: 2
Primeval Datarate: 2
ChannelsTxPower: 0
UpLinkCounter: 0
DownLinkCounter: 0

The device settings appear not to have returned to factory.

After some experimentation it looks like the only way to get a factory reset maybe re-flashing the device.

nanoFramework RAK811 LoRaWAN library Part2

Shield Serial

My initial RAK811 LPWAN Evaluation Board(EVB) test rig was based on an STM32F691DISCOVERY. I connected the EVB with jumper leads and sent the AT Command to request the LoRaWAN module version information

STM32F691Discovery with EVB connected with Jumpers
STM32F691Discovery with EVB connected with Jumpers

The STM32F691DISCOVERY board has an Arduino Uno R3 format socket which I wanted to be able to plug the EVB into. After removing R8,R17 & R19 I put the EVB on the STM32F691DISCOVERY and could still retrieve the RAK811 module version information.

STM32F691Discovery with EVB plugged into Arduino headers
The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.IoT.Rfm9x.ShieldSerial starting
COM5,COM6
TX: 12 bytes to output stream.
TX: 12 bytes via COM6
RXs :19 bytes read from COM6
RX sync:OK V3.0.0.13.H.T3

TX: 12 bytes to output stream.
TX: 12 bytes via COM6
RXs :19 bytes read from COM6
RX sync:OK V3.0.0.13.H.T3

RAK811 LPWAN EVB Part3

Invalidating the warranty…

I wanted the RAK811 LPWAN Evaluation Board(EVB) -AS923 to work with selection of my Arduino and nanoFramework devices. The first decision was which of the hardware serial port (D0,D1) or the software serial port (D10,D11) should be connected to P1?

To use the EVB with my STM32F691DISCOVERY board running the nanoFramework (COM5 on the hardware serial port pins D0,D1) I removed R17&R19.

After some tinkering, I found that R8 which is connected to the RAK811 module reset had to be cut as well for the shield to work on my Arduino Uno R3 and STM32F691DISCOVERY devices.

RAK811 EVB with R17,R19 & R8 cut

I can still run the Arduino Uno R3 and RAK811 EVB in the original configuration with a couple of jumper leads

RAK811 on Arduino with Serial connected to D10,D1 a SoftwareSerial port

For devices where I needed D10,D11 for a  Serial Peripheral Interface(SPI) I could use an FTDI board and a couple of other pins (in this case D2,D3) for serial logging.

RAK811 on Arduino with Serial connected to D2,D2 a SoftwareSerial port

After debugging some code I also replaced the small jumpers on P1 with a couple of jumper leads so it was less fiddly to swap from downloading to debugging.

nanoFramework RAK811 LoRaWAN library Part1

Invalidating the warranty

Over the last couple of days I have been working on a nanoFramework C# library for my RAK811 LPWAN Evaluation Board(EVB) from RAK Wireless which I have been using with an Arduino Uno R3 device. My initial test rig is based on an STM32F691DISCOVERY board which has Arduino Uno R3 format socket for the EVB.

My first step was to check what serial ports were available (COM5 & COM6) on the STM32F691Discovery and what pins they were connected to. (COM6 Arduino D0 & D1). Then check that these would work with the EVB pin assignments.

RAK 811 EVB schematic pg1
RAK 811 EVB schematic pg2

My first test was was a simple loopback based on the nanoFramework samples Serial Communications example.

STM32F691Discovery with jumper loopback
STM32F691Discovery with jumper loopback
//---------------------------------------------------------------------------------
// Copyright (c) June 2020, 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.
//
//---------------------------------------------------------------------------------
//#define ESP32_WROOM   //nanoff --target ESP32_WROOM_32 --serialport COM4 --update
//#define NETDUINO3_WIFI   // nanoff --target NETDUINO3_WIFI --update
//#define MBN_QUAIL // nanoff --target MBN_QUAIL --update
//#define ST_NUCLEO64_F091RC // nanoff --target ST_NUCLEO64_F091RC --update
//#define ST_NUCLEO144_F746ZG //nanoff --target ST_NUCLEO144_F746ZG --update
#define ST_STM32F769I_DISCOVERY      // nanoff --target ST_STM32F769I_DISCOVERY --update 
namespace devMobile.IoT.Rak811.ShieldSerial
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using Windows.Devices.SerialCommunication;
   using Windows.Storage.Streams;

#if ESP32_WROOM_32_LORA_1_CHANNEL
   using nanoFramework.Hardware.Esp32;
#endif

   public class Program
   {
#if ESP32_WROOM
      private const string SerialPortId = "";
#endif
#if NETDUINO3_WIFI
      private const string SpiBusId = "";
#endif
#if MBN_QUAIL
      private const string SpiBusId = "";
#endif
#if ST_NUCLEO64_F091RC
      private const string SpiBusId = "";
#endif
#if ST_NUCLEO144_F746ZG
      private const string SpiBusId = "";
#endif
#if ST_STM32F429I_DISCOVERY
      private const string SpiBusId = "";
#endif
#if ST_STM32F769I_DISCOVERY
      private const string SerialPortId = "COM6";
#endif

      public static void Main()
      {
         SerialDevice serialDevice;

         Debug.WriteLine("devMobile.IoT.Rfm9x.ShieldSerial starting");

         Debug.WriteLine(Windows.Devices.SerialCommunication.SerialDevice.GetDeviceSelector());

         try
         {
            // set GPIO functions for COM2 (this is UART1 on ESP32)
            #if ESP32_WROOM
               Configuration.SetPinFunction(Gpio.IO04, DeviceFunction.COM2_TX);
               Configuration.SetPinFunction(Gpio.IO05, DeviceFunction.COM2_RX);
            #endif
            serialDevice = SerialDevice.FromId(SerialPortId);

            // set parameters
            serialDevice.BaudRate = 9600;
            serialDevice.Parity = SerialParity.None;
            serialDevice.StopBits = SerialStopBitCount.One;
            serialDevice.Handshake = SerialHandshake.None;
            serialDevice.DataBits = 8;

            serialDevice.ReadTimeout = new TimeSpan(0, 0, 30);
            serialDevice.WriteTimeout = new TimeSpan(0, 0, 4);

            DataWriter outputDataWriter = new DataWriter(serialDevice.OutputStream);

            #if SERIAL_SYNC_READ
               DataReader inputDataReader = new DataReader(serialDevice.InputStream);
            #else
               serialDevice.DataReceived += SerialDevice_DataReceived;
            #endif

            // set a watch char to be notified when it's available in the input stream
            serialDevice.WatchChar = '\n';

            while (true)
            {
               uint bytesWritten = outputDataWriter.WriteString("at+version\r\n");
               Debug.WriteLine($"TX: {outputDataWriter.UnstoredBufferLength} bytes to output stream.");

               // calling the 'Store' method on the data writer actually sends the data
               uint txByteCount = outputDataWriter.Store();
               Debug.WriteLine($"TX: {txByteCount} bytes via {serialDevice.PortName}");

#if SERIAL_SYNC_READ
               uint bytesRead = inputDataReader.Load(50);

               Debug.WriteLine($"RXs :{bytesRead} bytes read from {serialDevice.PortName}");

               if (bytesRead > 0)
               {
                  String response = inputDataReader.ReadString(bytesRead);
                  Debug.WriteLine($"RX sync:{response}");
               }
#endif

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

      private static void SerialDevice_DataReceived(object sender, SerialDataReceivedEventArgs e)
      {
         switch(e.EventType)
         {
            case SerialData.Chars:
               //Debug.WriteLine("RX SerialData.Chars");
               break;

            case SerialData.WatchChar:
               Debug.WriteLine("RX: SerialData.WatchChar");
               SerialDevice serialDevice = (SerialDevice)sender;

               using (DataReader inputDataReader = new DataReader(serialDevice.InputStream))
               {
                  inputDataReader.InputStreamOptions = InputStreamOptions.Partial;

                  // read all available bytes from the Serial Device input stream
                  uint bytesRead = inputDataReader.Load(serialDevice.BytesToRead);

                  Debug.WriteLine($"RXa: {bytesRead} bytes read from {serialDevice.PortName}");

                  if (bytesRead > 0)
                  {
                     String response = inputDataReader.ReadString(bytesRead);
                     Debug.WriteLine($"RX:{response}");
                  }
               }
               break;
            default:
               Debug.Assert(false, $"e.EventType {e.EventType} unknown");
               break;
         }
      }
   }
}

After some tinkering I could successfully transmit and receive a string.

The next step was to connect my EVB and sent the AT Command to request the LoRaWAN module version information

STM32F691Discovery with EVB connected with Jumpers
STM32F691Discovery with EVB connected with Jumpers
The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.IoT.Rfm9x.ShieldSerial starting
COM5,COM6
TX: 12 bytes to output stream.
TX: 12 bytes via COM6
RX: SerialData.WatchChar
RXa: 19 bytes read from COM6
RX:OK V3.0.0.13.H.T3

TX: 12 bytes to output stream.
TX: 12 bytes via COM6
RX: SerialData.WatchChar
RXa: 19 bytes read from COM6
RX:OK V3.0.0.13.H.T3

The response was the same as I got with the RAK Serial Port Tool which was positive.

Version number check with RAK Serial Port tool

I need to do some more digging into how serialDevice.WatchChar = ‘\n’ works for synchronous reads.

Plus removing R17 & R19 there is no interaction with D11 & D10 which are normally used by the Serial Peripheral Interface(SPI) port so I can plug the shield directly into the STM32F691Discovery board.

My plan was to get an initial version of the library working with the STM32F691Discovery, then port it to the Netduino 3 Wifi (possible serial port pin issues) , ST_NUCLEO144_F746ZG, and ST_NUCLEO64_F091RC (possible issues with available flash).

RAK811 LPWAN EVB Part2

How can I use this…

Just over a week ago I purchased a RAK811 LPWAN Evaluation Board -AS923 and now I want to trial it with selection of devices and configurations.

Initially I didn’t want to modify the shield by removing resistors as I only have one, and I’m not certain what device(s) it will be used with. The initial hardware configuration required jumpers for the serial port, ground and 5V power.

Arduino Uno R3 and RAK811 LPWAN Evaluation board 5V config

After looking at the schematic it should be possible to use the shield with a 3v3 device.

RAK 811 EVB schematic pg1
RAK 811 EVB schematic pg2

I confirmed this with a Seeeduino V4.2 devices set to 3v3, by putting a jumper on J1 and shifting the jumper wire from the 5V to the 3V3 pin.

Seeeduino V4 and RAK811 LPWAN Evaluation board 3V3 config

The next step was to see how I could get the RAK shield working on other devices without jumpers. On Arduino Uno R3 devices D0&D1 are the hardware(HW) serial port which are used for uploading sketches, and diagnostic logging.

The shield also connects the module serial port to D0&D1 to D10&D11, so by removing R17&R19 the shield should work on a device This would also allow the use of the Serial Peripheral Interface(SPI) port for other applications.

Using the HW Serial port but without any logging.

Unplugging the jumpers to upload was painful but the lack of logging made it really hard to debug my code.

To get around this I configured a SoftwareSerial port on D2&D3 for logging.

/********************************************************
 * This demo is only supported after RUI firmware version 3.0.0.13.X on RAK811
 * Master Board Uart Receive buffer size at least 128 bytes. 
 ********************************************************/
//#define SERIAL_BUFFER_SIZE 128
//#define SERIAL_TX_BUFFER_SIZE 64
//#define SERIAL_RX_BUFFER_SIZE 128
//#define _SS_MAX_RX_BUFF 128
#include "RAK811.h"
#include "SoftwareSerial.h"
#define WORK_MODE LoRaWAN   //  LoRaWAN or LoRaP2P
#define JOIN_MODE OTAA    //  OTAA or ABP
#if JOIN_MODE == OTAA
String DevEui = "..."; // From TTN
String AppEui = "...";
String AppKey = "...";
#else JOIN_MODE == ABP
String NwkSKey = "...";
String AppSKey = "...";
String DevAddr = "...";
#endif

#define TXpin 3   // Set the virtual serial port pins
#define RXpin 2

SoftwareSerial DebugSerial(RXpin,TXpin); // Declare a virtual serial port for debugging
#define ATSerial Serial

char buffer[]= "48656C6C6F20776F726C6435";

bool InitLoRaWAN(void);
RAK811 RAKLoRa(ATSerial,DebugSerial);

void setup() {
  DebugSerial.begin(19200);
  DebugSerial.println(F("Starting"));
  while(DebugSerial.available())
  {
    DebugSerial.read(); 
  }
  
  ATSerial.begin(9600); //set ATSerial baudrate:This baud rate has to be consistent with  the baud rate of the WisNode device.
  while(ATSerial.available())
  {
    ATSerial.read(); 
  }

  if(!RAKLoRa.rk_setWorkingMode(0))  //set WisNode work_mode to LoRaWAN.
  {
    DebugSerial.println(F("set work_mode failed, please reset module."));
    while(1);
  }
  
  RAKLoRa.rk_getVersion();  //get RAK811 firmware version
  DebugSerial.println(RAKLoRa.rk_recvData());  //print version number

  DebugSerial.println(F("Start init RAK811 parameters..."));
 
  if (!InitLoRaWAN())  //init LoRaWAN
  {
    DebugSerial.println(F("Init error,please reset module.")); 
    while(1);
  }

  DebugSerial.println(F("Start to join LoRaWAN..."));
  while(!RAKLoRa.rk_joinLoRaNetwork(60))  //Joining LoRaNetwork timeout 60s
  {
    DebugSerial.println();
    DebugSerial.println(F("Rejoin again after 5s..."));
    delay(5000);
  }
  DebugSerial.println(F("Join LoRaWAN success"));

  if(!RAKLoRa.rk_isConfirm(0))  //set LoRa data send package type:0->unconfirm, 1->confirm
  {
    DebugSerial.println(F("LoRa data send package set error,please reset module.")); 
    while(1);    
  }
}

bool InitLoRaWAN(void)
{
  if(RAKLoRa.rk_setJoinMode(JOIN_MODE))  //set join_mode:OTAA
  {
    if(RAKLoRa.rk_setRegion(0))  //set region EU868
    {
      if (RAKLoRa.rk_initOTAA(DevEui, AppEui, AppKey))
      {
        DebugSerial.println(F("RAK811 init OK!"));  
        return true;    
      }
    }
  }
  return false;
}

void loop() 
{
  DebugSerial.println(F("Start send data..."));
  if (RAKLoRa.rk_sendData(1, buffer))
  {    
    //for (unsigned long start = millis(); millis() - start < 300000L;)
    for (unsigned long start = millis(); millis() - start < 10000L;)
    {
      String ret = RAKLoRa.rk_recvData();
      if(ret != NULL)
      { 
        DebugSerial.println("ret != NULL");
        DebugSerial.println(ret);
      }
      if((ret.indexOf("OK")>0)||(ret.indexOf("ERROR")>0))
      {
        DebugSerial.println(F("Go to Sleep."));
        RAKLoRa.rk_sleep(1);  //Set RAK811 enter sleep mode
        delay(10000);  //delay 10s
        RAKLoRa.rk_sleep(0);  //Wakeup RAK811 from sleep mode
        break;
      }
    }
  }
}

I used an FTDI module I had lying around to connect the diagnostic logging serial port on the test rig to my development box.

Using the HW Serial port but with logging.

Now I only had to unplug the jumpers for D0&D1 and change ports in the Arduino IDE. One port for debugging the other for downloading.

Depending on the application I may remove R8 so I can manually reset the shield.

RAK811 LPWAN EVB Part1

I followed the instructions…

Just over a week ago I purchased some gear from RAK Wireless, the shipping was reasonable, it arrived promptly, and was well packaged. I had ordered

I figured a good first project would be to get the evaluation board going with one of my older Arduino Uno R3 devices following the Interfacing your RAK811 LPWAN Evaluation Board with Arduino Boards instructions.

The evaluation board was in its own box along with a USB cable, some spare PCB jumpers, some jumper leads and an antenna labeled with the frequency band which was thoughtful.

Arduino Uno R3 and RAK811 LPWAN Evaluation board 5V config

I downloaded the specified library from the RAK Wireless Github repository extracted the contents and copied the V1.3 directory into the libraries folder of my Arduino IDE install.

I updated the module software to the latest using the tools provided in the github download and checked this with the RAK Serial Port tool over the Universal Serial Bus(USB) connection (make sure the jumpers next to the antenna connection are set correctly)

Version number check with RAK Serial Port tool

I created a new project based on JoinNetworkOTAA (Over the Air Activation) example.

/********************************************************
 * This demo is only supported after RUI firmware version 3.0.0.13.X on RAK811
 * Master Board Uart Receive buffer size at least 128 bytes. 
 ********************************************************/

#include "RAK811.h"
#include "SoftwareSerial.h"
#define WORK_MODE LoRaWAN   //  LoRaWAN or LoRaP2P
#define JOIN_MODE OTAA    //  OTAA or ABP
#if JOIN_MODE == OTAA
String DevEui = "8680000000000001";
String AppEui = "70B3D57ED00285A7";
String AppKey = "DDDFB1023885FBFF74D3A55202EDF2B1";
#else JOIN_MODE == ABP
String NwkSKey = "69AF20AEA26C01B243945A28C9172B42";
String AppSKey = "841986913ACD00BBC2BE2479D70F3228";
String DevAddr = "260125D7";
#endif
#define TXpin 11   // Set the virtual serial port pins
#define RXpin 10
#define DebugSerial Serial
SoftwareSerial ATSerial(RXpin,TXpin);    // Declare a virtual serial port
char buffer[]= "72616B776972656C657373";

bool InitLoRaWAN(void);
RAK811 RAKLoRa(ATSerial,DebugSerial);


void setup() {
  DebugSerial.begin(115200);
  while(DebugSerial.available())
  {
    DebugSerial.read(); 
  }
  
  ATSerial.begin(9600); //set ATSerial baudrate:This baud rate has to be consistent with  the baud rate of the WisNode device.
  while(ATSerial.available())
  {
    ATSerial.read(); 
  }

  if(!RAKLoRa.rk_setWorkingMode(0))  //set WisNode work_mode to LoRaWAN.
  {
    DebugSerial.println(F("set work_mode failed, please reset module."));
    while(1);
  }
  
  RAKLoRa.rk_getVersion();  //get RAK811 firmware version
  DebugSerial.println(RAKLoRa.rk_recvData());  //print version number

  DebugSerial.println(F("Start init RAK811 parameters..."));
 
  if (!InitLoRaWAN())  //init LoRaWAN
  {
    DebugSerial.println(F("Init error,please reset module.")); 
    while(1);
  }

  DebugSerial.println(F("Start to join LoRaWAN..."));
  while(!RAKLoRa.rk_joinLoRaNetwork(60))  //Joining LoRaNetwork timeout 60s
  {
    DebugSerial.println();
    DebugSerial.println(F("Rejoin again after 5s..."));
    delay(5000);
  }
  DebugSerial.println(F("Join LoRaWAN success"));

  if(!RAKLoRa.rk_isConfirm(0))  //set LoRa data send package type:0->unconfirm, 1->confirm
  {
    DebugSerial.println(F("LoRa data send package set error,please reset module.")); 
    while(1);    
  }
}

bool InitLoRaWAN(void)
{
  if(RAKLoRa.rk_setJoinMode(JOIN_MODE))  //set join_mode:OTAA
  {
    if(RAKLoRa.rk_setRegion(0))  //set region EU868
    {
      if (RAKLoRa.rk_initOTAA(DevEui, AppEui, AppKey))
      {
        DebugSerial.println(F("RAK811 init OK!"));  
        return true;    
      }
    }
  }
  return false;
}

void loop() {
  DebugSerial.println(F("Start send data..."));
  if (RAKLoRa.rk_sendData(1, buffer))
  {    
    for (unsigned long start = millis(); millis() - start < 90000L;)
    {
      String ret = RAKLoRa.rk_recvData();
      if(ret != NULL)
      { 
        DebugSerial.println(ret);
      }
      if((ret.indexOf("OK")>0)||(ret.indexOf("ERROR")>0))
      {
        DebugSerial.println(F("Go to Sleep."));
        RAKLoRa.rk_sleep(1);  //Set RAK811 enter sleep mode
        delay(10000);  //delay 10s
        RAKLoRa.rk_sleep(0);  //Wakeup RAK811 from sleep mode
        break;
      }
    }
  }
}

I had to look at the library code to work out the value the rk_setRegion call needed for the AS932 band used in my region

bool RAK811::rk_setRegion(int region)
{
  if (region > 9)
  {
    _serial1.println(F("Parameter error"));
    return false;
  }
  String REGION;
  switch (region)
  {
    case 0:REGION="AS923";
      break;
    case 1:REGION="AU915";
      break;
    case 2:REGION="CN470";
      break;
    case 3:REGION="CN779";
      break;
    case 4:REGION="EU433";
      break;
    case 5:REGION="EU868";
      break;
    case 6:REGION="KR920";
      break;
    case 7:REGION="IN865";
      break;
    case 8:REGION="US915";
      break;
    case 9:REGION="US915_Hybrid";
      break;
  }
  _serial1.println("Current work region: "+REGION);
  sendRawCommand("at+set_config=lora:region:" + REGION);
  ret = rk_recvData();
#if defined DEBUG_MODE
  _serial1.println(ret);
#endif
  if (ret.indexOf("OK") >= 0)
  {
    return true;
  }
  else
  {
    return false;
  }
}

I compiled the code, uploaded it to my device and it didn’t work…

Arduino monitor output showing rk_setWorkingMode failing

I then had a look at the Arduino library code and enabled some of the commented out diagnostic println statements. At the time it did seem odd there were no responses from the module.

Arduino monitor output showing rk_setWorkingMode failing with debugging

I had noticed some odd characters in the RAK Serial Port Tool while checking version numbers etc.

Setting work Mode with RAK Serial Port Tool

It looked like maybe the serial port was having some issues, so I double checked my modification of the HardwareSerial.h file and began to wonder (as the binary size wasn’t changing) if I had the right file. After some research I found there are several copies of that file and I wasn’t modifying the correct one.

Multiple locations of HardwareSerial.h

Then I realised that the port sending AT Commands to the module was actually a SoftwareSerial port not a hardware one. I then tried changing the size of the software serial buffers but still was having problems.

Arduino tool with default buffer sizes (833 bytes)
Arduino tool with non-default buffer sizes (961 bytes)

I then tried recompiling with different settings to see if the serial port issues would stop. The global variables size changed which showed I had the right files/settings but the code still didn’t work.

Going back over my settings I tried the command used in the rk_setWorkingMode call in the RAK Serial Port Tool and it worked.

I then then went for a walk and when I came back I realised the module speed was set to 115200 baud by default (which it is). I then used at+set_config=device:uart:1:9600 (don’t forget to press <enter> at end of the line) to set baud rate to match the code.

Setting device to 9600 baud

I then changed the jumpers and ran the software again…

So, it looks like the RAK811 module was set to 115200 baud (web based setup instructions), but the later library versions were 9600 baud, but the instructions didn’t mention the need to change the speed with the RAK Serial port tool.

Image of code and setup from RAK instructions

Now that my device is trying to connect to a network I need to configure the LoRaWAN network settings. I’m going to use the RAK7246G LPWAN Developer Gateway and the nationwide LoRaWAN network operated by Spark in New Zealand.