.Net Meadow RFM95/96/97/98 LoRa library Part8

Transmit and Receive with Interrupts

For the final iteration of the “nasty” test harness I got the interrupts working for the transmitting and receiving of messages. It’s not quite simultaneous, the code sends a message every 10 seconds then goes back to receive continuous mode after each message has been sent.

      public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin, IPin resetPin, IPin interruptPin)
      {
         // Chip select pin configuration
         ChipSelectGpioPin = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
         if (ChipSelectGpioPin == null)
         {
            Console.WriteLine("ChipSelectGpioPin == null");
         }

         // Factory reset pin configuration
         IDigitalOutputPort resetGpioPin = device.CreateDigitalOutputPort(resetPin);
         if (resetGpioPin == null)
         {
            Console.WriteLine("resetGpioPin == null");
         }
         resetGpioPin.State = false;
         Task.Delay(10);
         resetGpioPin.State = true;
         Task.Delay(10);

         // Interrupt pin for RX message & TX done notification 
         InterruptGpioPin = device.CreateDigitalInputPort(interruptPin, InterruptMode.EdgeRising);
         InterruptGpioPin.Changed += InterruptGpioPin_ValueChanged;

         Rfm9XLoraModem = new SpiPeripheral(spiBus, ChipSelectGpioPin);
         if (Rfm9XLoraModem == null)
         {
            Console.WriteLine("Rfm9XLoraModem == null");
         }
      }

      private void InterruptGpioPin_ValueChanged(object sender, DigitalInputPortEventArgs args)
      {
         byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
         byte numberOfBytes = 0;
         string messageText = "";
         bool transmitDone = false;

         //Console.WriteLine(string.Format("RegIrqFlags:{0}", Convert.ToString(irqFlags, 2).PadLeft(8, '0')));
         if ((irqFlags & 0b01000000) == 0b01000000)
         {
            //Console.WriteLine("Receive-Message");
            byte currentFifoAddress = this.RegisterReadByte(0x10); // RegFifiRxCurrent
            this.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr

            numberOfBytes = this.RegisterReadByte(0x13); // RegRxNbBytes
            byte[] messageBytes = this.RegisterRead(0x00, numberOfBytes); // RegFifo
            messageText = UTF8Encoding.UTF8.GetString(messageBytes);
         }

         if ((irqFlags & 0b00001000) == 0b00001000)  // TxDone
         {
            this.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous
            transmitDone = true;
         }

         this.RegisterWriteByte(0x40, 0b00000000); // RegDioMapping1 0b00000000 DI0 RxReady & TxReady
         this.RegisterWriteByte(0x12, 0xff);// RegIrqFlags
         if (numberOfBytes > 0)
         {
            Console.WriteLine("Received {0} byte message {1}", numberOfBytes, messageText);
         }
         if(transmitDone)
         {
            Console.WriteLine("Transmit-Done");
         }
      }
...
   public class MeadowApp : App<F7Micro, MeadowApp>
   {
      private Rfm9XDevice rfm9XDevice;
      private byte NessageCount = Byte.MaxValue;

      public MeadowApp()
      {
         ISpiBus spiBus = Device.CreateSpiBus(500);
         if (spiBus == null)
         {
            Console.WriteLine("spiBus == null");
         }

         rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11, Device.Pins.D10);

         // Put device into LoRa + Sleep mode
         rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode 

         // Set the frequency to 915MHz
         byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
         rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

         rfm9XDevice.RegisterWriteByte(0x0F, 0x0); // RegFifoRxBaseAddress 

         rfm9XDevice.RegisterWriteByte(0x09, 0b10000000); // RegPaConfig

         rfm9XDevice.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous

         while (true)
         {
            rfm9XDevice.RegisterWriteByte(0x0E, 0x0); // RegFifoTxBaseAddress 

            // Set the Register Fifo address pointer
            rfm9XDevice.RegisterWriteByte(0x0D, 0x0); // RegFifoAddrPtr 

            string messageText = "W10 IoT Core LoRa! " + NessageCount.ToString();
            NessageCount -= 1;

            // load the message into the fifo
            byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);
            rfm9XDevice.RegisterWrite(0x0, messageBytes); // RegFifo 

            // Set the length of the message in the fifo
            rfm9XDevice.RegisterWriteByte(0x22, (byte)messageBytes.Length); // RegPayloadLength
            Console.WriteLine("Sending {0} bytes message {1}", messageBytes.Length, messageText);
            rfm9XDevice.RegisterWriteByte(0x40, 0b01000000); // RegDioMapping1 0b00000000 DI0 RxReady & TxReady
            rfm9XDevice.RegisterWriteByte(0x01, 0b10000011); // RegOpMode 

            Debug.WriteLine("Sending {0} bytes message {1}", messageBytes.Length, messageText);

            Task.Delay(10000).Wait();
         }
      }

The diagnostic output shows inbound and outbound messages (Arduino then Meadow diagnostics)

21:15:56.070 -> 0x1: 0x81
21:15:56.070 -> 0x2: 0x1A
…
21:15:57.527 -> 0x7E: 0x0
21:15:57.527 -> 0x7F: 0x0
21:15:57.527 -> LoRa init succeeded.
21:15:58.101 -> Sending HeLoRa World! 0
21:16:06.958 -> Message: W10 IoT Core LoRa! 254
21:16:06.991 -> RSSI: -60
21:16:06.991 -> Snr: 9.50
21:16:06.991 ->
21:16:09.062 -> Sending HeLoRa World! 2
21:16:17.184 -> Message: W10 IoT Core LoRa! 253
21:16:17.218 -> RSSI: -61
21:16:17.218 -> Snr: 9.75
21:16:17.218 ->
21:16:19.876 -> Sending HeLoRa World! 4
21:16:21.946 -> Message: ⸮LoRaIoT1Maduino2at 65.3,ah 70,wsa 6,wsg 12,wd 167.25,r 0.00,
21:16:22.014 -> RSSI: -76
21:16:22.014 -> Snr: 9.50
21:16:22.014 ->
21:16:27.406 -> Message: W10 IoT Core LoRa! 252
21:16:27.429 -> RSSI: -60
21:16:27.429 -> Snr: 9.50
21:16:27.429 ->
21:16:30.153 -> Sending HeLoRa World! 6
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveTransmitInterrupt\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveTransmitInterrupt\bin\Debug\net472\Meadow.dll'. 
The program '[42104] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[42104] App.exe' has exited with code 0 (0x0).
 .
 .
 DirectRegisterAccess = True
 .
 .
 Sending 22 bytes message W10 IoT Core LoRa! 255
 Transmit-Done
 Received 15 byte message HeLoRa World! 0
 Sending 22 bytes message W10 IoT Core LoRa! 254
 Transmit-Done
 Received 15 byte message HeLoRa World! 2
 Sending 22 bytes message W10 IoT Core LoRa! 253
 Transmit-Done
 Received 15 byte message HeLoRa World! 4
 Received 61 byte message ???LoRaIoT1Maduino2at 65.3,ah 70,wsa 6,wsg 12,wd 167.25,r 0.00,
 Sending 22 bytes message W10 IoT Core LoRa! 252
 Transmit-Done
 Received 15 byte message HeLoRa World! 6
 Sending 22 bytes message W10 IoT Core LoRa! 251
 Transmit-Done
 Received 15 byte message HeLoRa World! 8
 Sending 22 bytes message W10 IoT Core LoRa! 250
 Transmit-Done
 Received 16 byte message HeLoRa World! 10
 Sending 22 bytes message W10 IoT Core LoRa! 249
 Transmit-Done
 Received 16 byte message HeLoRa World! 12
 Received 40 byte message ???LoRaIoT1#)#???c???h 55,t 24.9,s 3,v 4.01
 Sending 22 bytes message W10 IoT Core LoRa! 248
 Transmit-Done
 Received 16 byte message HeLoRa World! 14
 Sending 22 bytes message W10 IoT Core LoRa! 247
 Transmit-Done
 Received 16 byte message ???LoRaIoT1Maduino
 Sending 22 bytes message W10 IoT Core LoRa! 246
 Transmit-Done
 Received 16 byte message HeLoRa World! 18
 Sending 22 bytes message W10 IoT Core LoRa! 245
 Transmit-Done
 Received 16 byte message HeLoRa World! 20
 Sending 22 bytes message W10 IoT Core LoRa! 244
 Transmit-Done
 Received 16 byte message HeLoRa World! 22
 Sending 22 bytes message W10 IoT Core LoRa! 243
 Transmit-Done
 Received 16 byte message HeLoRa World! 24
 Sending 22 bytes message W10 IoT Core LoRa! 242
 Transmit-Done

The RegIrqFlags 01011000 indicates the RxDone, ValidHeader, and TxDone flags were set which was what I was expecting. Note the interference, the 46 byte packet

Next step is some refactoring to extract the register access code and merging with my Windows 10 IoT Core RMF9X library code base.

.Net Meadow RFM95/96/97/98 LoRa library Part7

Transmit Interrupt

Starting with the TransmitBasic sample application I modified the code so that a hardware interrupt (specified in RegDioMapping1) was generated on TxDone (FIFO Payload Transmission completed).

The application inserts a message into the RFM95 transmit FIFO every 10 seconds with confirmation of transmission displayed shortly afterwards

      public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin, IPin resetPin, IPin interruptPin)
      {
         // Chip select pin configuration
         ChipSelectGpioPin = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
         if (ChipSelectGpioPin == null)
         {
            Console.WriteLine("ChipSelectGpioPin == null");
         }

         // Factory reset pin configuration
         IDigitalOutputPort resetGpioPin = device.CreateDigitalOutputPort(resetPin);
         if (resetGpioPin == null)
         {
            Console.WriteLine("resetGpioPin == null");
         }
         resetGpioPin.State = false;
         Task.Delay(10);
         resetGpioPin.State = true;
         Task.Delay(10);

         // Interrupt pin for RX message & TX done notification 
         InterruptGpioPin = device.CreateDigitalInputPort(interruptPin, InterruptMode.EdgeRising);
         InterruptGpioPin.Changed += InterruptGpioPin_ValueChanged;

         Rfm9XLoraModem = new SpiPeripheral(spiBus, ChipSelectGpioPin);
         if (Rfm9XLoraModem == null)
         {
            Console.WriteLine("Rfm9XLoraModem == null");
         }
      }

      private void InterruptGpioPin_ValueChanged(object sender, DigitalInputPortEventArgs args)
      {
        byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
        this.RegisterWriteByte(0x12, 0xff);// Clear RegIrqFlags

        //Console.WriteLine(string.Format("RegIrqFlags:{0}", Convert.ToString(irqFlags, 2).PadLeft(8, '0')));
         if ((irqFlags & 0b00001000) == 0b00001000)  // TxDone
         {
            Console.WriteLine("Transmit-Done");
         }
      }
…
   public class MeadowApp : App<F7Micro, MeadowApp>
   {
      private Rfm9XDevice rfm9XDevice;

      public MeadowApp()
      {
         ISpiBus spiBus = Device.CreateSpiBus(500);
         if (spiBus == null)
         {
            Console.WriteLine("spiBus == null");
         }

         rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11, Device.Pins.D10);

         // Put device into LoRa + Sleep mode
         rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode 

         // Set the frequency to 915MHz
         byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
         rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

         // More power PA Boost
         rfm9XDevice.RegisterWriteByte(0x09, 0b10000000); // RegPaConfig

         // Interrupt on TxDone
         rfm9XDevice.RegisterWriteByte(0x40, 0b01000000); // RegDioMapping1 0b00000000 DI0 TxDone

         while (true)
         {
            // Set the Register Fifo address pointer
            rfm9XDevice.RegisterWriteByte(0x0E, 0x00); // RegFifoTxBaseAddress 

            // Set the Register Fifo address pointer
            rfm9XDevice.RegisterWriteByte(0x0D, 0x0); // RegFifoAddrPtr 

            string messageText = "Hello LoRa!";

            // load the message into the fifo
            byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);
            rfm9XDevice.RegisterWrite(0x0, messageBytes); // RegFifo 

            // Set the length of the message in the fifo
            rfm9XDevice.RegisterWriteByte(0x22, (byte)messageBytes.Length); // RegPayloadLength
            Console.WriteLine("Sending {0} bytes message {1}", messageBytes.Length, messageText);
            rfm9XDevice.RegisterWriteByte(0x01, 0b10000011); // RegOpMode 

            Task.Delay(10000).Wait();
         }
      }
   }

The output in the debug window

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitInterrupt\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitInterrupt\bin\Debug\net472\Meadow.dll'. 
The program '[11164] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[11164] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
.
.
Sending 11 bytes message Hello LoRa!
Transmit-Done
Sending 11 bytes message Hello LoRa!
Transmit-Done
Sending 11 bytes message Hello LoRa!
Transmit-Done

On the Arduino test client the serial monitor displayed

13:02:09.098 -> Sending HeLoRa World! 4
13:02:19.130 -> Message: ⸮LoRaIoT1Maduino2at 79.7,ah 39,wsa 6,wsg 13,wd 28.13,r 0.00,
13:02:19.177 -> RSSI: -72
13:02:19.177 -> Snr: 9.25
13:02:19.177 -> 
13:02:19.431 -> Sending HeLoRa World! 6
13:02:29.994 -> Sending HeLoRa World! 8
13:02:32.000 -> Message: Hello LoRa!
13:02:32.000 -> RSSI: -46
13:02:32.047 -> Snr: 9.50
13:02:32.047 -> 
13:02:40.750 -> Sending HeLoRa World! 10
13:02:42.260 -> Message: Hello LoRa!
13:02:42.260 -> RSSI: -45
13:02:42.314 -> Snr: 9.50
13:02:42.314 -> 
13:02:51.286 -> Sending HeLoRa World! 12
13:02:52.541 -> Message: Hello LoRa!
13:02:52.541 -> RSSI: -45
13:02:52.541 -> Snr: 9.75
13:02:52.541 -> 
13:03:02.112 -> Sending HeLoRa World! 14
13:03:02.745 -> Message: Hello LoRa!
13:03:02.745 -> RSSI: -45
13:03:02.792 -> Snr: 9.50
13:03:02.792 -> 

Now that I’m confident my hardware is all working the next step will be building a full featured client based on my Windows 10 IoT Core library.

.Net Meadow RFM95/96/97/98 LoRa library Part6

Receive Interrupt

This proof of concept (PoC) was to confirm I could configure the Semtech 127X then handle the received messages using a Meadow event handler. The event handler code is based on the implementation in my Windows IoT 10 Core library.

I had added a few Console.WriteLine statements (Debug.Print currently doesn’t work Dec 2019) so I could see what was going on. But, using Console.WriteLine in the event handler caused me some problems which I had to debug. The irqFlags bit mask indicated there was a message in the FIFO but it wasn’t displayed and the interrupt mask wasn’t getting reset. As a temporary fix I refactored the code so the Console.WriteLine was the last statement in the EventHandler(which may cause other issues).

public Rfm9XDevice(IIODevice device, ISpiBus spiBus, IPin chipSelectPin, IPin resetPin, IPin interruptPin)
      {
         // Chip select pin configuration
         ChipSelectGpioPin = device.CreateDigitalOutputPort(chipSelectPin, initialState: true);
         if (ChipSelectGpioPin == null)
         {
            Console.WriteLine("ChipSelectGpioPin == null");
         }

         // Factory reset pin configuration
         IDigitalOutputPort resetGpioPin = device.CreateDigitalOutputPort(resetPin);
         if (resetGpioPin == null)
         {
            Console.WriteLine("resetGpioPin == null");
         }
         resetGpioPin.State = false;
         Task.Delay(10);
         resetGpioPin.State = true;
         Task.Delay(10);

         // Interrupt pin for RX message & TX done notification 
         InterruptGpioPin = device.CreateDigitalInputPort(interruptPin, InterruptMode.EdgeRising);
         InterruptGpioPin.Changed += InterruptGpioPin_ValueChanged;

         Rfm9XLoraModem = new SpiPeripheral(spiBus, ChipSelectGpioPin);
         if (Rfm9XLoraModem == null)
         {
            Console.WriteLine("Rfm9XLoraModem == null");
         }
      }
...
      private void InterruptGpioPin_ValueChanged(object sender, DigitalInputPortEventArgs args)
      {
         byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
         byte numberOfBytes = 0;
         string messageText = "";

         //Console.WriteLine(string.Format("RegIrqFlags:{0}", Convert.ToString(irqFlags, 2).PadLeft(8, '0')));
         if ((irqFlags & 0b01000000) == 0b01000000)
         {
            //Console.WriteLine("Receive-Message");
            byte currentFifoAddress = this.RegisterReadByte(0x10); // RegFifiRxCurrent
            this.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr

            numberOfBytes = this.RegisterReadByte(0x13); // RegRxNbBytes
            byte[] messageBytes = this.RegisterRead(0x00, numberOfBytes); // RegFifo
            messageText = UTF8Encoding.UTF8.GetString(messageBytes);
         }

         this.RegisterWriteByte(0x12, 0xff);// RegIrqFlags
         if (numberOfBytes > 0)
         {
            Console.WriteLine("Received {0} byte message {1}", numberOfBytes, messageText);
         }
      }
...
public class MeadowApp : App
{
private Rfm9XDevice rfm9XDevice;
  public MeadowApp()
  {
     ISpiBus spiBus = Device.CreateSpiBus(500);
     if (spiBus == null)
     {
        Console.WriteLine("spiBus == null");
     }

     rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11, Device.Pins.D10);

     // Put device into LoRa + Sleep mode
     rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode 

     // Set the frequency to 915MHz
     byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
     rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

     rfm9XDevice.RegisterWriteByte(0x0F, 0x0); // RegFifoRxBaseAddress 

     rfm9XDevice.RegisterWriteByte(0x40, 0b00000000); // RegDioMapping1 0b00000000 DI0 RxReady & TxReady

     rfm9XDevice.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous

     rfm9XDevice.RegisterDump();

     Console.WriteLine("Receive-Wait");
     Task.Delay(-1).Wait();
  }
}

The output in the output debug window looked like this

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveInterrupt\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveInterrupt\bin\Debug\net472\Meadow.dll'. 
The program '[40348] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[40348] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
.
.
Register dump
Register 0x00 - Value 0X6c - Bits 01101100
…
Register 0x42 - Value 0X12 - Bits 00010010
Receive-Wait
Received 15 byte message HeLoRa World! 0
Received 59 byte message ???LoRaIoT1Maduino2at 57.2,ah 67,wsa 1,wsg 3,wd 56.63,r 0.00,
Received 15 byte message HeLoRa World! 2
Received 15 byte message HeLoRa World! 4
Received 15 byte message HeLoRa World! 6
Received 15 byte message HeLoRa World! 8
Received 16 byte message HeLoRa World! 10

Next steps will be wiring up the transmit done interrupt, then building a full featured client based on my Windows 10 IoT Core library.

.Net Meadow RFM95/96/97/98 LoRa library Part5

Receive Basic

For testing this code I used the same version of the LoRaSetSyncWord example as Transmit Basic

20:57:40.239 -> LoRa init succeeded.
20:57:40.759 -> Sending HeLoRa World! 0
20:57:40.968 -> Message: ⸮LoRaIoT1Maduino2at 57.7,ah 64,wsa 1,wsg 2,wd 88.13,r 0.00,
20:57:41.036 -> RSSI: -72
20:57:41.036 -> Snr: 9.50
20:57:41.036 -> 
20:57:51.766 -> Sending HeLoRa World! 2
20:58:02.532 -> Sending HeLoRa World! 4
20:58:12.845 -> Sending HeLoRa World! 6
20:58:23.434 -> Sending HeLoRa World! 8
20:58:34.190 -> Sending HeLoRa World! 10
20:58:42.005 -> Message: ⸮LoRaIoT1Maduino2at 57.6,ah 64,wsa 2,wsg 5,wd 74.25,r 0.00,
20:58:42.074 -> RSSI: -72
20:58:42.074 -> Snr: 9.75

The Meadow code builds on my Windows 10 IoT Core Receive Basic and the Meadow Transmit Basic samples.

public class MeadowApp : App<F7Micro, MeadowApp>
{
	private Rfm9XDevice rfm9XDevice;

	public MeadowApp()
	{
		ISpiBus spiBus = Device.CreateSpiBus(500);
		if (spiBus == null)
		{
			Console.WriteLine("spiBus == null");
		}

		rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11);

		// Put device into LoRa + Sleep mode
		rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode 

		// Set the frequency to 915MHz
		byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
		rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

		rfm9XDevice.RegisterWriteByte(0x0F, 0x0); // RegFifoRxBaseAddress 

		rfm9XDevice.RegisterWriteByte(0x01, 0b10000101); // RegOpMode set LoRa & RxContinuous

		while (true)
		{
			// Wait until a packet is received, no timeouts in PoC
			Console.WriteLine("Receive-Wait");
			byte IrqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
			while ((IrqFlags & 0b01000000) == 0)  // wait until RxDone cleared
			{
				Task.Delay(100).Wait();
				IrqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
				Console.Write(".");
			}
			Console.WriteLine("");
			Console.WriteLine(string.Format("RegIrqFlags {0}", Convert.ToString((byte)IrqFlags, 2).PadLeft(8, '0')));
			Console.WriteLine("Receive-Message");
			byte currentFifoAddress = rfm9XDevice.RegisterReadByte(0x10); // RegFifiRxCurrent
			rfm9XDevice.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr

			byte numberOfBytes = rfm9XDevice.RegisterReadByte(0x13); // RegRxNbBytes

			byte[] messageBytes = rfm9XDevice.RegisterRead(0x00, numberOfBytes); // RegFifo

			rfm9XDevice.RegisterWriteByte(0x0d, 0);
			rfm9XDevice.RegisterWriteByte(0x12, 0b11111111); // RegIrqFlags clear all the bits

			string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
			Console.WriteLine("Received {0} byte message {1}", messageBytes.Length, messageText);

			Console.WriteLine("Receive-Done");
		}
	}
}

The receive code works reliably but has no error detection or correction capability, so every so often a message gets corrupted. Which is can be seen in the Debug output below.

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveBasic\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\ReceiveBasic\bin\Debug\net472\Meadow.dll'. 
The program '[18208] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[18208] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
.
.
Receive-Wait
RegIrqFlags 01010000
Receive-Message
Received 61 byte message ???LoRaIoT1Maduino2at 57.7,ah 64,wsa 2,wsg 4,wd 254.25,r 0.00,
Receive-Done
Receive-Wait
RegIrqFlags 01110000
Receive-Message
Received 60 byte message ???LoReE??????!???ngvyno2at,57/7-ah 6???,w???a 2,w?????????6,7$.13,r 0.00-
Receive-Done
Receive-Wait
RegIrqFlags 01010000
Receive-Message
Received 16 byte message HeLoRa World! 0
Receive-Done
Receive-Wait
RegIrqFlags 01000000
Receive-Message
Received 60 byte message ???LoRaIoT1Maduino2at 57.7,ah 64,wsa 1,wsg 2,wd 88.13,r 0.00,
Receive-Done
Receive-Wait
RegIrqFlags 01010000
Receive-Message
Received 16 byte message HeLoRa World! 2
Receive-Done
Receive-Wait

I will look at implementing some sort of carrier-sense multiple access with collision avoidance solution to reduce the number of corrupted messages when two (or possibly more devices) transmit at the same time.

Transmitting/receiving with interrupts or design goals next.

.Net Meadow RFM95/96/97/98 LoRa library Part4

Transmit Basic

I had a couple of Armtronix IA005 SX1276 loRa nodes sitting on my desk from a recent post so I used one of them running a modified version of the Arduino LoRa library LoRaSetSyncWord example to receive messages from my Meadow device.

/*
  LoRa Duplex communication with Sync Word
 
  Sends a message every half second, and polls continually
  for new incoming messages. Sets the LoRa radio's Sync Word.
 
  Spreading factor is basically the radio's network ID. Radios with different
  Sync Words will not receive each other's transmissions. This is one way you
  can filter out radios you want to ignore, without making an addressing scheme.
 
  See the Semtech datasheet, http://www.semtech.com/images/datasheet/sx1276.pdf
  for more on Sync Word.
 
  created 28 April 2017
  by Tom Igoe
*/
#include <stdlib.h>
#include <LoRa.h>
const int csPin = PA4;          // LoRa radio chip select
const int resetPin = PC13;       // LoRa radio reset
const int irqPin = PA11;         // change for your board; must be a hardware interrupt pin
 
byte msgCount = 0;            // count of outgoing messages
int interval = 2000;          // interval between sends
long lastSendTime = 0;        // time of last packet send
 
void setup() {
  Serial.begin(9600);                   // initialize serial
  while (!Serial);
 
  Serial.println("LoRa Duplex - Set sync word");
 
  // override the default CS, reset, and IRQ pins (optional)
  LoRa.setPins(csPin, resetPin, irqPin);// set CS, reset, IRQ pin
 
  if (!LoRa.begin(915E6)) {             // initialize ratio at 915 MHz
    Serial.println("LoRa init failed. Check your connections.");
    while (true);                       // if failed, do nothing
  }
 
  LoRa.setSyncWord(0x12);           // ranges from 0-0xFF, default 0x34, see API docs
 
  LoRa.dumpRegisters(Serial);
  Serial.println("LoRa init succeeded.");
}
 
void loop() {
  if (millis() - lastSendTime > interval) {
    String message = "HeLoRa World! ";   // send a message
    message += msgCount;
    sendMessage(message);
    Serial.println("Sending " + message);
    lastSendTime = millis();            // timestamp the message
    interval = random(1000) + 10000;    // 10-11 seconds
    msgCount++;
  }
 
  // parse for a packet, and call onReceive with the result:
  onReceive(LoRa.parsePacket());
}
 
void sendMessage(String outgoing) {
  LoRa.beginPacket();                   // start packet
  LoRa.print(outgoing);                 // add payload
  LoRa.endPacket();                     // finish packet and send it
  msgCount++;                           // increment message ID
}
 
void onReceive(int packetSize) {
  if (packetSize == 0) return;          // if there's no packet, return
 
  // read packet header bytes:
  String incoming = "";
 
  while (LoRa.available()) {
    incoming += (char)LoRa.read();
  }
 
  Serial.println("Message: " + incoming);
  Serial.println("RSSI: " + String(LoRa.packetRssi()));
  Serial.println("Snr: " + String(LoRa.packetSnr()));
  Serial.println();
}

The Meadow application

	public class MeadowApp : App<F7Micro, MeadowApp>
	{
		private Rfm9XDevice rfm9XDevice;

		public MeadowApp()
		{
			ISpiBus spiBus = Device.CreateSpiBus(500);
			if (spiBus == null)
			{
				Console.WriteLine("spiBus == null");
			}

			rfm9XDevice = new Rfm9XDevice(Device, spiBus, Device.Pins.D09, Device.Pins.D11);

			// Put device into LoRa + Sleep mode
			rfm9XDevice.RegisterWriteByte(0x01, 0b10000000); // RegOpMode 

			// Set the frequency to 915MHz
			byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 }; // RegFrMsb, RegFrMid, RegFrLsb
			rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

			// More power PA Boost
			rfm9XDevice.RegisterWriteByte(0x09, 0b10000000); // RegPaConfig

			while (true)
			{
				rfm9XDevice.RegisterWriteByte(0x0E, 0x0); // RegFifoTxBaseAddress 

				// Set the Register Fifo address pointer
				rfm9XDevice.RegisterWriteByte(0x0D, 0x0); // RegFifoAddrPtr 

				string messageText = "Hello LoRa!";

				// load the message into the fifo
				byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);
				foreach (byte b in messageBytes)
				{
					rfm9XDevice.RegisterWriteByte(0x0, b); // RegFifo
				}

				// Set the length of the message in the fifo
				rfm9XDevice.RegisterWriteByte(0x22, (byte)messageBytes.Length); // RegPayloadLength

				Console.WriteLine("Sending {0} bytes message {1}", messageBytes.Length, messageText);
				/// Set the mode to LoRa + Transmit
				rfm9XDevice.RegisterWriteByte(0x01, 0b10000011); // RegOpMode 

				// Wait until send done, no timeouts in PoC
				Console.WriteLine("Send-wait");
				byte IrqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
				while ((IrqFlags & 0b00001000) == 0)  // wait until TxDone cleared
				{
					Task.Delay(10).Wait();
					IrqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
					Console.Write(".");
				}
				Console.WriteLine("");
				rfm9XDevice.RegisterWriteByte(0x12, 0b00001000); // clear TxDone bit
				Console.WriteLine("Send-Done");

				Task.Delay(30000).Wait();
			}
		}

When I ran the meadow application after some messing around with the jumper wires.

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitBasic\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFM9X.Meadow\TransmitBasic\bin\Debug\net472\Meadow.dll'. 
The program '[37572] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[37572] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
.
.
Sending 11 bytes message Hello LoRa!
Send-wait
Send-Done
Sending 11 bytes message Hello LoRa!
Send-wait
.
Send-Done

I could the see the messages arriving at the Armtronix device in the Arduino monitor (the other messages in the monitor are my solar powered weather station and soil moisture monitoring node).

12:47:55.198 -> Sending HeLoRa World! 10
12:48:05.745 -> Sending HeLoRa World! 12
12:48:06.663 -> Message: ⸮LoRaIoT1Maduino2at 85.8,ah 19,wsa 5,wsg 8,wd 123.38,r 0.00,
12:48:06.730 -> RSSI: -71
12:48:06.730 -> Snr: 10.00
12:48:06.730 ->
12:48:08.770 -> Message: Hello LoRa!
12:48:08.770 -> RSSI: -47
12:48:08.804 -> Snr: 9.00
12:48:08.804 ->
12:48:16.555 -> Sending HeLoRa World! 14
12:48:26.847 -> Sending HeLoRa World! 16
12:48:37.154 -> Sending HeLoRa World! 18
12:48:39.469 -> Message: Hello LoRa!
12:48:39.469 -> RSSI: -46
12:48:39.536 -> Snr: 9.00
12:48:39.536 ->
12:48:47.311 -> Sending HeLoRa World! 20
12:48:58.094 -> Sending HeLoRa World! 22
12:49:07.748 -> Message: ⸮LoRaIoT1Maduino2at 86.0,ah 19,wsa 5,wsg 15,wd 155.63,r 0.00,
12:49:07.817 -> RSSI: -71
12:49:07.817 -> Snr: 9.50
12:49:07.817 ->
12:49:08.464 -> Sending HeLoRa World! 24
12:49:10.097 -> Message: Hello LoRa!
12:49:10.097 -> RSSI: -46
12:49:10.130 -> Snr: 9.75
12:49:10.130 ->
12:49:19.373 -> Sending HeLoRa World! 26
12:49:30.125 -> Sending HeLoRa World! 28
12:49:40.262 -> Sending HeLoRa World! 30
12:49:40.671 -> Message: Hello LoRa!
12:49:40.671 -> RSSI: -46
12:49:40.705 -> Snr: 9.25
12:49:40.705 ->
12:49:50.725 -> Sending HeLoRa World! 32
12:50:01.081 -> Sending HeLoRa World! 34
12:50:08.800 -> Message: ⸮LoRaIoT1Maduino2at 85.6,ah 19,wsa 5,wsg 11,wd 159.00,r 0.00,
12:50:08.868 -> RSSI: -72
12:50:08.868 -> Snr: 10.00
12:50:08.868 ->
12:50:11.219 -> Message: Hello LoRa!
12:50:11.219 -> RSSI: -46
12:50:11.252 -> Snr: 9.25
12:50:11.252 ->
12:50:11.526 -> Sending HeLoRa World! 36
12:50:21.731 -> Sending HeLoRa World! 38
12:50:32.696 -> Sending HeLoRa World! 40
12:50:41.741 -> Message: Hello LoRa!
12:50:41.741 -> RSSI: -46
12:50:41.775 -> Snr: 9.25
12:50:41.775 ->
12:50:43.685 -> Sending HeLoRa World! 42
12:50:54.566 -> Sending HeLoRa World! 44
12:51:05.604 -> Sending HeLoRa World! 46
12:51:09.852 -> Message: ⸮LoRaIoT1Maduino2at 85.3,ah 19,wsa 2,wsg 8,wd 150.75,r 0.00,
12:51:09.954 -> RSSI: -71
12:51:09.954 -> Snr: 9.50
12:51:09.954 ->
12:51:12.400 -> Message: Hello LoRa!
12:51:12.400 -> RSSI: -46
12:51:12.433 -> Snr: 9.00
12:51:12.433 ->
12:51:16.511 -> Sending HeLoRa World! 48
12:51:27.530 -> Sending HeLoRa World! 50
12:51:37.796 -> Sending HeLoRa World! 52
12:51:42.968 -> Message: Hello LoRa!
12:51:42.968 -> RSSI: -45
12:51:43.003 -> Snr: 9.25
12:51:43.003 ->
12:51:48.389 -> Sending HeLoRa World! 54
12:51:59.052 -> Sending HeLoRa World! 56
12:52:09.251 -> Sending HeLoRa World! 58
12:52:10.912 -> Message: ⸮LoRaIoT1Maduino2at 85.1,ah 19,wsa 2,wsg 6,wd 84.00,r 0.00,
12:52:11.013 -> RSSI: -70
12:52:11.013 -> Snr: 9.75
12:52:11.013 ->
12:52:13.546 -> Message: Hello LoRa!
12:52:13.546 -> RSSI: -46
12:52:13.581 -> Snr: 9.75
12:52:13.581 ->

This PoC code is getting a bit nasty with magic numbers and no error checking. The next step is getting a basic packet receive working…

.Net Meadow RFM95/96/97/98 LoRa library Part1

After writing Windows 10 IoT Core & .NetMF RFM9X libraries I figured a port to a Wilderness Labs Meadow device shouldn’t be “rocket science”.

To get started I used a Dragino LoRa shield for Arduino which looked compatible with my Meadow device.

Dragino shield schematic

The shield ships with the SPI lines configured for ICSP so the three jumpers diagonally across the shield from the antenna connector need to be swapped to the side closest to the edge of the shield.

Dragino Arduino shield based test harness
//---------------------------------------------------------------------------------
// Copyright (c) Dec 2019, 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.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x
{
   using System;
   using System.Threading.Tasks;
   using Meadow;
   using Meadow.Devices;
   using Meadow.Hardware;

   public class MeadowApp : App<F7Micro, MeadowApp>
   {
      const byte RegVersion = 0x42;
      ISpiBus spiBus;
      SpiPeripheral sx127xDevice;
      IDigitalOutputPort spiPeriphChipSelect;

      public MeadowApp()
      {
         ConfigureSpiPort();
         //ReadDeviceID();
         ReadDeviceIDDiy();
      }

      public void ConfigureSpiPort()
      {
         try
         {
            spiBus = Device.CreateSpiBus(500);
            if (spiBus == null)
            {
               Console.WriteLine("spiBus == null");
            }

            Console.WriteLine("Creating SPI NSS Port...");
            spiPeriphChipSelect = Device.CreateDigitalOutputPort(Device.Pins.D09);
            if (spiPeriphChipSelect == null)
            {
               Console.WriteLine("spiPeriphChipSelect == null");
            }
   
            Console.WriteLine("sx127xDevice Device...");
            sx127xDevice = new SpiPeripheral(spiBus, spiPeriphChipSelect);
            if (sx127xDevice == null)
            {
               Console.WriteLine("sx127xDevice == null");
            }

            Console.WriteLine("ConfigureSpiPort Done...");
         }
         catch (Exception ex)
         {
            Console.WriteLine("ConfigureSpiPort " + ex.Message);
         }
      }

      
      public void ReadDeviceID()
      {
         Task.Delay(500).Wait();

         while (true)
         {
            try
            {
               Console.WriteLine("sx127xDevice.ReadRegister...1");

               byte registerValue = sx127xDevice.ReadRegister(RegVersion);

               Console.WriteLine("sx127xDevice.ReadRegister...2");

               Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", RegVersion, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
            }
            catch (Exception ex)
            {
               Console.WriteLine("ReadDeviceID " + ex.Message);
            }

            Task.Delay(10000).Wait();
         }
      }

      public void ReadDeviceIDDiy()
      {
         var txBuffer = new byte[2];
         var rxBuffer = new byte[2];

         Task.Delay(500).Wait();

         while (true)
         {
            try
            {
               Console.WriteLine("spiBus.ExchangeData...1");

               txBuffer[0] = RegVersion;

               spiBus.ExchangeData(spiPeriphChipSelect, ChipSelectMode.ActiveLow, txBuffer, rxBuffer, 2);

               Console.WriteLine("spiBus.ExchangeData...2");

               byte registerValue = rxBuffer[1];

               Console.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", RegVersion, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));
            }
            catch (Exception ex)
            {
               Console.WriteLine("ReadDeviceIDDiy " + ex.Message);
            }

            Task.Delay(10000).Wait();
         }
      }
   }
}

After some trial and error (using beta 3.6) I found that the ReadRegister method didn’t work as expected (possibly related to this issue) and I had to manually assemble the request to read the SX127X RegVersion register.

'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll'. 
'App.exe' (CLR v4.0.30319: DefaultDomain): Loaded 'C:\Users\BrynLewis\source\repos\RFX9X.Meadow\FeatherWingSPI\bin\Debug\net472\App.exe'. Symbols loaded.
'App.exe' (CLR v4.0.30319: App.exe): Loaded 'C:\Users\BrynLewis\source\repos\RFX9X.Meadow\FeatherWingSPI\bin\Debug\net472\Meadow.dll'. 
The program '[22324] App.exe: Program Trace' has exited with code 0 (0x0).
The program '[22324] App.exe' has exited with code 0 (0x0).
.
.
DirectRegisterAccess = True
==========================================================
Ignore the exceptions generated by the DateTime call here.
==========================================================
.
Creating SPI NSS Port...
sx127xDevice Device...
ConfigureSpiPort Done...
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2
Register 0x42 - Value 0X12 - Bits 00010010
spiBus.ExchangeData...1
spiBus.ExchangeData...2

Armtronix IA005 SX1276 loRa node

A month ago I ordered a pair of IA005: SX1276 Lora node STM32F103 devices from the Armtronix shop on Tindie for evaluation. At USD18 each these devices were competitively priced and I was interested in trialling another maple like device.

Bill of materials (Prices as at December 2019)

  • IA005 SX1276 loRa node USD36 (USD18 each)
  • Grove – Temperature&Humidity Sensor USD11.5
  • Grove – 4 pin Female Jumper to Grove 4 pin Conversion Cable USD3.90
Armtronix device with Seeedstudio temperature & humidity sensor

I used a modified version of my Arduino client code which worked after I got the pins sorted and the female jumper sockets in the right order.

/*
  Copyright ® 2019 December devMobile Software, All Rights Reserved

  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
  PURPOSE.

  You can do what you want with this code, acknowledgment would be nice.

  http://www.devmobile.co.nz

*/
#include <stdlib.h>
#include <LoRa.h>
#include <TH02_dev.h>

//#define DEBUG
//#define DEBUG_TELEMETRY
//#define DEBUG_LORA

// LoRa field gateway configuration (these settings must match your field gateway)
const char FieldGatewayAddress[] = {"LoRaIoT1"};
const char DeviceAddress[] = {"ArmTronix01"};
const float FieldGatewayFrequency =  915000000.0;
const byte FieldGatewaySyncWord = 0x12 ;

// Payload configuration
const int ChipSelectPin = PA4;
const int InterruptPin = PA11;
const int ResetPin = PC13;

// LoRa radio payload configuration
const byte SensorIdValueSeperator = ' ' ;
const byte SensorReadingSeperator = ',' ;
const int LoopSleepDelaySeconds = 30 ;

const byte PayloadSizeMaximum = 64 ;
byte payload[PayloadSizeMaximum];
byte payloadLength = 0 ;


void setup()
{
  Serial.begin(9600);
#ifdef DEBUG
  while (!Serial);
#endif
  Serial.println("Setup called");

  Serial.println("LoRa setup start");
  
  // override the default chip select and reset pins
  LoRa.setPins(ChipSelectPin, ResetPin, InterruptPin); 
  if (!LoRa.begin(FieldGatewayFrequency))
  {
    Serial.println("LoRa begin failed");
    while (true); // Drop into endless loop requiring restart
  }

  // Need to do this so field gateways pays attention to messsages from this device
  LoRa.enableCrc();
  LoRa.setSyncWord(FieldGatewaySyncWord);

#ifdef DEBUG_LORA
  LoRa.dumpRegisters(Serial);
#endif
  Serial.println("LoRa Setup done.");

  // Configure the Seeedstudio TH02 temperature & humidity sensor
  Serial.println("TH02 setup start");
  TH02.begin();
  delay(100);
  Serial.println("TH02 setup done");

  PayloadHeader((byte*)FieldGatewayAddress,strlen(FieldGatewayAddress), (byte*)DeviceAddress, strlen(DeviceAddress));

  Serial.println("Setup done");
  Serial.println();
}


void loop()
{
  float temperature ;
  float humidity ;

  Serial.println("Loop called");

  PayloadReset();

  // Read the temperature & humidity & battery voltage values then display nicely
  temperature = TH02.ReadTemperature();
  Serial.print("T:");
  Serial.print( temperature, 1 ) ;
  Serial.println( "C " ) ;

  PayloadAdd( "T", temperature, 1);

  humidity = TH02.ReadHumidity();
  Serial.print("H:");
  Serial.print( humidity, 0 ) ;
  Serial.println( "% " ) ;

  PayloadAdd( "H", humidity, 0) ;

#ifdef DEBUG_TELEMETRY
  Serial.print( "RFM9X/SX127X Payload len:");
  Serial.print( payloadLength );
  Serial.println( " bytes" );
#endif

  LoRa.beginPacket();
  LoRa.write( payload, payloadLength );
  LoRa.endPacket();

  Serial.println("Loop done");
  Serial.println();
  delay(LoopSleepDelaySeconds * 1000l);
}


void PayloadHeader( byte *to, byte toAddressLength, byte *from, byte fromAddressLength)
{
  byte addressesLength = toAddressLength + fromAddressLength ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadHeader- ");
  Serial.print( "To len:");
  Serial.print( toAddressLength );
  Serial.print( " From len:");
  Serial.print( fromAddressLength );
  Serial.print( " Header len:");
  Serial.print( addressesLength );
  Serial.println( );
#endif

  payloadLength = 0 ;

  // prepare the payload header with "To" Address length (top nibble) and "From" address length (bottom nibble)
  payload[payloadLength] = (toAddressLength << 4) | fromAddressLength ;
  payloadLength += 1;

  // Copy the "To" address into payload
  memcpy(&payload[payloadLength], to, toAddressLength);
  payloadLength += toAddressLength ;

  // Copy the "From" into payload
  memcpy(&payload[payloadLength], from, fromAddressLength);
  payloadLength += fromAddressLength ;
}


void PayloadAdd( const char *sensorId, float value, byte decimalPlaces)
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-float ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value, decimalPlaces );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( dtostrf(value, -1, decimalPlaces, (char *)&payload[payloadLength]));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;
  
#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadAdd( const char *sensorId, int value )
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-int ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif  

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( itoa( value,(char *)&payload[payloadLength],10));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;
  
#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadAdd( const char *sensorId, unsigned int value )
{
  byte sensorIdLength = strlen( sensorId ) ;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadAdd-unsigned int ");
  Serial.print( "SensorId:");
  Serial.print( sensorId );
  Serial.print( " Len:");
  Serial.print( sensorIdLength );
  Serial.print( " Value:");
  Serial.print( value );
  Serial.print( " payloadLen:");
  Serial.print( payloadLength);
#endif  

  memcpy( &payload[payloadLength], sensorId,  sensorIdLength) ;
  payloadLength += sensorIdLength ;
  payload[ payloadLength] = SensorIdValueSeperator;
  payloadLength += 1 ;
  payloadLength += strlen( utoa( value,(char *)&payload[payloadLength],10));
  payload[ payloadLength] = SensorReadingSeperator;
  payloadLength += 1 ;

#ifdef DEBUG_TELEMETRY
  Serial.print( " payloadLen:");
  Serial.println( payloadLength);
#endif
}


void PayloadReset()
{
  byte fromAddressLength = payload[0] & 0xf ;
  byte toAddressLength = payload[0] >> 4 ;
  byte addressesLength = toAddressLength + fromAddressLength ;

  payloadLength = addressesLength + 1;

#ifdef DEBUG_TELEMETRY
  Serial.print("PayloadReset- ");
  Serial.print( "To len:");
  Serial.print( toAddressLength );
  Serial.print( " From len:");
  Serial.print( fromAddressLength );
  Serial.print( " Header len:");
  Serial.println( addressesLength );
#endif
}

To get the application to download I had to configure the board in the Arduino IDE

Then change the jumpers

Initially I had some problems deploying my software because I hadn’t followed the instructions (the wiki everyone referred to appeared to be offline) and run the installation batch file (New dev machine since my previous maple based project).

15:40:56.207 -> LoRa Setup done.
15:40:56.207 -> TH02 setup start
15:40:56.307 -> TH02 setup done
15:40:56.307 -> PayloadHeader- To len:8 From len:11 Header len:19
15:40:56.354 -> Setup done
15:40:56.354 -> 
15:40:56.354 -> Loop called
15:40:56.354 -> PayloadReset- To len:8 From len:11 Header len:19
15:40:56.408 -> T:23.9C 
15:40:56.408 -> PayloadAdd-float SensorId:T Len:1 Value:23.9 payloadLen:20 payloadLen:27
15:40:56.508 -> H:70% 
15:40:56.508 -> PayloadAdd-float SensorId:H Len:1 Value:70 payloadLen:27 payloadLen:32
15:40:56.608 -> RFM9X/SX127X Payload len:32 bytes
15:40:56.655 -> Loop done
15:40:56.655 -> 
15:41:26.647 -> Loop called
15:41:26.647 -> PayloadReset- To len:8 From len:11 Header len:19
15:41:26.684 -> T:24.0C 
15:41:26.730 -> PayloadAdd-float SensorId:T Len:1 Value:24.0 payloadLen:20 payloadLen:27
15:41:26.784 -> H:69% 
15:41:26.784 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:41:26.884 -> RFM9X/SX127X Payload len:32 bytes
15:41:26.931 -> Loop done
15:41:26.931 -> 
15:41:56.904 -> Loop called
15:41:56.904 -> PayloadReset- To len:8 From len:11 Header len:19
15:41:56.948 -> T:24.1C 
15:41:56.982 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:41:57.054 -> H:69% 
15:41:57.054 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:41:57.157 -> RFM9X/SX127X Payload len:32 bytes
15:41:57.191 -> Loop done
15:41:57.191 -> 
15:42:27.211 -> Loop called
15:42:27.211 -> PayloadReset- To len:8 From len:11 Header len:19
15:42:27.258 -> T:24.1C 
15:42:27.258 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:42:27.343 -> H:69% 
15:42:27.343 -> PayloadAdd-float SensorId:H Len:1 Value:69 payloadLen:27 payloadLen:32
15:42:27.427 -> RFM9X/SX127X Payload len:32 bytes
15:42:27.481 -> Loop done
15:42:27.481 -> 
15:42:57.504 -> Loop called
15:42:57.504 -> PayloadReset- To len:8 From len:11 Header len:19
15:42:57.504 -> T:24.1C 
15:42:57.550 -> PayloadAdd-float SensorId:T Len:1 Value:24.1 payloadLen:20 payloadLen:27
15:42:57.604 -> H:68% 
15:42:57.604 -> PayloadAdd-float SensorId:H Len:1 Value:68 payloadLen:27 payloadLen:32
15:42:57.704 -> RFM9X/SX127X Payload len:32 bytes
15:42:57.755 -> Loop done
15:42:57.755 -> 

I configured the device to upload to my Azure IoT Hub/Azure IoT Central gateway and it has been running reliably for a couple of days.

Azure IoT Central temperature and humidity values

Initially I had some configuration problems but I contacted Armtronix support and they promptly provided a couple of updated links for product and device documentation.