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.
I created a new ABP device
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.
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.
devMobile's blog 