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.

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