915 MHz Payload Addressing client

Posted on September 17, 2018 by devmobilenz

This is a demo Netduino client (based on one of the examples in my RFM9XLoRaNetMF library) that uploads telemetry data to my Windows 10 IoT Core on Raspberry PI field gateway proof of concept(PoC).

Bill of materials (Prices Sep 2018)

Netduino 3 USD40
Seeedstudio Base shield V2 USD8.90 NZD14.00
Seeedstudio Temperature&Humidity Sensor USD11.50 NZD20
5CM 4 Pin buckled cable USD1.90 NZD34.75
Lora Shield
- Dragino 915MHz USD21.00
- Elecrow 915MHz USD15.90
- MakerFabs 433MHz USD15.60

//---------------------------------------------------------------------------------
// Copyright (c) 2017, 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.Netduino.FieldGateway
{
   using System;
   using System.Text;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;
   using devMobile.IoT.NetMF.ISM;
   using devMobile.NetMF.Sensor;

   class NetduinoClient
   {
      Rfm9XDevice rfm9XDevice;
      private readonly TimeSpan dueTime = new TimeSpan(0, 0, 15);
      private readonly TimeSpan periodTime = new TimeSpan(0, 0, 300);
      private readonly SiliconLabsSI7005 sensor = new SiliconLabsSI7005();
      private readonly OutputPort _led = new OutputPort(Pins.ONBOARD_LED, false);
      private readonly byte[] fieldGatewayAddress = Encoding.UTF8.GetBytes("LoRaIoT1");
      private readonly byte[] deviceAddress = Encoding.UTF8.GetBytes("Netduino1");

      public NetduinoClient()
      {
         rfm9XDevice = new Rfm9XDevice(Pins.GPIO_PIN_D10, Pins.GPIO_PIN_D9, Pins.GPIO_PIN_D2);
      }

      public void Run()
      {
         //rfm9XDevice.Initialise(frequency: 915000000, paBoost: true, rxPayloadCrcOn: true);
         rfm9XDevice.Initialise(frequency: 433000000, paBoost: true, rxPayloadCrcOn: true);
         rfm9XDevice.Receive(deviceAddress);

         rfm9XDevice.OnDataReceived += rfm9XDevice_OnDataReceived;
         rfm9XDevice.OnTransmit += rfm9XDevice_OnTransmit;

         Timer humidityAndtemperatureUpdates = new Timer(HumidityAndTemperatureTimerProc, null, dueTime, periodTime);

         Thread.Sleep(Timeout.Infinite);
      }

      private void HumidityAndTemperatureTimerProc(object state)
      {
         _led.Write(true);

         double humidity = sensor.Humidity();
         double temperature = sensor.Temperature();

         Debug.Print(DateTime.UtcNow.ToString("hh:mm:ss") + " H:" + humidity.ToString("F1") + " T:" + temperature.ToString("F1"));

         rfm9XDevice.Send(fieldGatewayAddress, Encoding.UTF8.GetBytes( "t " + temperature.ToString("F1") + ",H " + humidity.ToString("F0")));

         _led.Write(true);
      }

      void rfm9XDevice_OnTransmit()
      {
         Debug.Print("Transmit-Done");
         _led.Write(false);
      }

      void rfm9XDevice_OnDataReceived(byte[] address, float packetSnr, int packetRssi, int rssi, byte[] data)
      {
         try
         {
            string messageText = new string(UTF8Encoding.UTF8.GetChars(data));
            string addressText = new string(UTF8Encoding.UTF8.GetChars(address));

            Debug.Print(DateTime.UtcNow.ToString("HH:MM:ss") + "-Rfm9X PacketSnr " + packetSnr.ToString("F1") + " Packet RSSI " + packetRssi + "dBm RSSI " + rssi + "dBm = " + data.Length + " byte message " + @"""" + messageText + @"""");
         }
         catch (Exception ex)
         {
            Debug.Print(ex.Message);
         }
      }
   }
}

The code is available on GitHub
FieldGatewayNetduinoLoRaElecrow915
Elecrow shield
FieldGatewayNetduinoLoRaDragino915
Dragino shield
FieldGatewayNetduinLoRaMakerFabs433
MakerFabs shield
Net Micro Framework debug output from device

The thread '' (0x2) has exited with code 0 (0x0).
12:00:18 H:96.9 T:19.6
Transmit-Done
12:05:17 H:95.1 T:20.1
Transmit-Done

.Net Framework debug output Field Gateway

The thread 0x1550 has exited with code 0 (0x0).
21:21:49-RX From Netduino1 PacketSnr 9.5 Packet RSSI -40dBm RSSI -107dBm = 11 byte message "t 19.6,H 97"
 Sensor Netduino1t Value 19.6
 Sensor Netduino1H Value 97
 AzureIoTHubClient SendEventAsync start
 AzureIoTHubClient SendEventAsync finish
...
21:26:49-RX From Netduino1 PacketSnr 9.5 Packet RSSI -33dBm RSSI -103dBm = 11 byte message "t 20.1,H 95"
 Sensor Netduino1t Value 20.1
 Sensor Netduino1H Value 95
 AzureIoTHubClient SendEventAsync start
 AzureIoTHubClient SendEventAsync finish
The thread 0xfbc has exited with code 0 (0x0).

Then in my Azure IoT Hub

AzureIOTHubExplorerScreenGrab20180917

.Net MicroFramework LoRa library Part8

Posted on August 21, 2018 by devmobilenz

Receive Interrupt

After getting interrupts to work for outbound messages I changed the interrupt pin D10 mapping and the interrupt mask.

Getting this working with my RPI meant the process went relatively smoothly.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.ReceiveInterrupt
{
   using System;
   using System.Text;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public sealed class Rfm9XDevice
   {
      private const byte RegisterAddressReadMask = 0X7f;
      private const byte RegisterAddressWriteMask = 0x80;

      private SPI Rfm9XLoraModem = null;
      private OutputPort ResetGpioPin = null;
      private InterruptPort InterruptPin = null;

      public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin resetPin, Cpu.Pin interruptPin)
      {
         // Factory reset pin configuration
         ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
         ResetGpioPin.Write(false);
         Thread.Sleep(10);
         ResetGpioPin.Write(true);
         Thread.Sleep(10);

         this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

         InterruptPin = new InterruptPort(interruptPin, false, Port.ResistorMode.Disabled, Port.InterruptMode.InterruptEdgeHigh);

         InterruptPin.OnInterrupt += InterruptPin_OnInterrupt;

         Thread.Sleep(100);
      }

      public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin reset)
      {
         // Factory reset pin configuration
         ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
         ResetGpioPin.Write(false);
         Thread.Sleep(10);
         ResetGpioPin.Write(true);
         Thread.Sleep(10);

         this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

         Thread.Sleep(100);
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] writeBuffer = new byte[] { registerAddress };
         byte[] readBuffer = new byte[1];
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);

         return readBuffer[0];
      }

      public ushort RegisterReadWord(byte address)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[2];
         Debug.Assert(Rfm9XLoraModem != null);

         readBuffer[0] = RegisterReadByte(address);
         readBuffer[1] = RegisterReadByte(address += 1);

         return (ushort)(readBuffer[1] + (readBuffer[0] << 8));
      }

      public byte[] RegisterRead(byte address, int length)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[length];
         Debug.Assert(Rfm9XLoraModem != null);

         for (byte index = 0; index < length; index++)
         {
            readBuffer[index] = RegisterReadByte(address += 1);
         }

         return readBuffer;
      }

      public void RegisterWriteByte(byte address, byte value)
      {
         byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterWriteWord(byte address, ushort value)
      {
         byte[] valueBytes = BitConverter.GetBytes(value);
         byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, valueBytes[0], valueBytes[1] };
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterWrite(byte address, byte[] bytes)
      {
         byte[] writeBuffer = new byte[1 + bytes.Length];
         Debug.Assert(Rfm9XLoraModem != null);

         Array.Copy(bytes, 0, writeBuffer, 1, bytes.Length);
         writeBuffer[0] = address |= RegisterAddressWriteMask;

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterDump()
      {
         Debug.Print("---Registers 0x00 thru 0x42---");
         for (byte registerIndex = 0; registerIndex  4];

         // Mask off the upper 4 bits to get the rest of it.
         hexString += hexChars[singlebyte & 0x0F];

         return hexString;
      }

      private static string WordToHexString(ushort singleword)
      {
         string hexString = string.Empty;

         byte[] bytes = BitConverter.GetBytes(singleword);

         hexString += ByteToHexString(bytes[1]);

         hexString += ByteToHexString(bytes[0]);

         return hexString;
      }

      public class Program
      {
         public static void Main()
         {
            Rfm9XDevice rfm9XDevice = new Rfm9XDevice(Pins.GPIO_PIN_D10, Pins.GPIO_PIN_D9, Pins.GPIO_PIN_D2);
            byte MessageCount = byte.MinValue;

            // Put device into LoRa + Sleep mode
            rfm9XDevice.RegisterWriteByte(0x01, 0x80); // 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, 0x0); // RegDioMapping1 0b00000000 DIO0 RxReady & TxReady

            rfm9XDevice.RegisterWriteByte(0x01, 0x85); // RegOpMode set LoRa & RxContinuous

            Thread.Sleep(Timeout.Infinite);
         }
      }
   }
}

In the Visual Studio debug output window I could see received packets

'Microsoft.SPOT.Debugger.CorDebug.dll' (Managed): Loaded 'C:\Program Files (x86)\Secret Labs\Netduino SDK\Assemblies\v4.3\le\SecretLabs.NETMF.Hardware.dll', Symbols loaded.
The thread '' (0x2) has exited with code 0 (0x0).
RegIrqFlags 50
Receive-Message
Received 28 byte message Hello W10 IoT Core LoRa! 247
RegIrqFlags 50
Receive-Message
Received 28 byte message Hello W10 IoT Core LoRa! 246
RegIrqFlags 50
Receive-Message

Next, I’ll integrate the .NetMF receive and transmit interrupt examples, and then refactor the code to extract the RFM9X code into a reusable module.

.Net MicroFramework LoRa library Part7

Posted on August 20, 2018 by devmobilenz

Transmit Interrupt

Starting with the TransmitBasic sample application I modified the code so that a hardware interrupt (specified by SX1276 RegDioMapping1) was generated on TxDone (FIFO Payload Transmission completed).

The application inserts a message into the SX1276 transmit FIFO every 10 seconds with confirmation of transmission displayed shortly afterwards

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.TransmitInterrupt
{
	using System;
	using System.Text;
	using System.Threading;
	using Microsoft.SPOT;
	using Microsoft.SPOT.Hardware;
	using SecretLabs.NETMF.Hardware.Netduino;

	public sealed class Rfm9XDevice
	{
		private const byte RegisterAddressReadMask = 0X7f;
		private const byte RegisterAddressWriteMask = 0x80;

		private SPI Rfm9XLoraModem = null;
		private OutputPort ResetGpioPin = null;
		private InterruptPort InterruptPin = null;

		public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin resetPin, Cpu.Pin interruptPin)
		{
			// Factory reset pin configuration
			ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
			ResetGpioPin.Write(false);
			Thread.Sleep(10);
			ResetGpioPin.Write(true);
			Thread.Sleep(10);

			this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

			InterruptPin = new InterruptPort(interruptPin, false, Port.ResistorMode.Disabled, Port.InterruptMode.InterruptEdgeHigh);

			InterruptPin.OnInterrupt += InterruptPin_OnInterrupt;

			Thread.Sleep(100);
		}

		public Byte RegisterReadByte(byte registerAddress)
		{
			byte[] writeBuffer = new byte[] { registerAddress };
			byte[] readBuffer = new byte[1];
			Debug.Assert(Rfm9XLoraModem != null);

			Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);

			return readBuffer[0];
		}

		public ushort RegisterReadWord(byte address)
		{
			byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
			byte[] readBuffer = new byte[2];
			Debug.Assert(Rfm9XLoraModem != null);

			readBuffer[0] = RegisterReadByte(address);
			readBuffer[1] = RegisterReadByte(address += 1);

			return (ushort)(readBuffer[1] + (readBuffer[0] << 8));
		}

		public byte[] RegisterRead(byte address, int length)
		{
			byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
			byte[] readBuffer = new byte[length];
			Debug.Assert(Rfm9XLoraModem != null);

			for (byte index = 0; index  4];

			// Mask off the upper 4 bits to get the rest of it.
			hexString += hexChars[singlebyte & 0x0F];

			return hexString;
		}

		private static string WordToHexString(ushort singleword)
		{
			string hexString = string.Empty;

			byte[] bytes = BitConverter.GetBytes(singleword);

			hexString += ByteToHexString(bytes[1]);

			hexString += ByteToHexString(bytes[0]);

			return hexString;
		}

		void InterruptPin_OnInterrupt(uint data1, uint data2, DateTime time)
		{
			byte IrqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
			Debug.Print("RegIrqFlags " + ByteToHexString(IrqFlags));

			if ((IrqFlags & 0x08) == 0x08)  // TxDone
			{
				Debug.Print("Transmit-Done");
			}

			this.RegisterWriteByte(0x12, 0xff);// RegIrqFlags
		}

		public class Program
		{
			public static void Main()
			{
				Rfm9XDevice rfm9XDevice = new Rfm9XDevice(Pins.GPIO_PIN_D10, Pins.GPIO_PIN_D9, Pins.GPIO_PIN_D2);
				byte MessageCount = byte.MinValue;

				while (true)
				{
					// Put device into LoRa + Sleep mode
					rfm9XDevice.RegisterWriteByte(0x01, 0x80); // 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, 0x80); // RegPaConfig

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

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

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

						string messageText = "Hello NetMF LoRa! ";
						if (MessageCount != 0)
						{
							messageText += "-" + MessageCount.ToString();
						}
						else
						{
							messageText += MessageCount.ToString();
						}
						MessageCount += 1;

						// 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

						Debug.Print("Sending " + messageBytes.Length + " bytes message " + messageText);
						/// Set the mode to LoRa + Transmit
						rfm9XDevice.RegisterWriteByte(0x01, 0x83); // RegOpMode 

						Thread.Sleep(10000);
					}
				}
			}
		}

	}
}

Unlike the Windows 10 IoT core version I can configure the interrupt to only trigger on the leading edge.

InterruptPin = new InterruptPort(interruptPin, false, Port.ResistorMode.Disabled, Port.InterruptMode.InterruptEdgeHigh);

In the Debug output window of VS2K12 I could see

The thread '' (0x2) has exited with code 0 (0x0).
Sending 19 bytes message Hello NetMF LoRa! 0
RegIrqFlags 08
Transmit-Done
Sending 20 bytes message Hello NetMF LoRa! -1
RegIrqFlags 08
Transmit-Done
Sending 20 bytes message Hello NetMF LoRa! -2
RegIrqFlags 08
Transmit-Done

On my Arduino device the message arrived

LoRa Receiver Callback
Received packet 'Hello NetMF LoRa! 0' with RSSI -29
Received packet 'Hello NetMF LoRa! -1' with RSSI -29
Received packet 'Hello NetMF LoRa! -2' with RSSI -29
Received packet 'Hello NetMF LoRa! -3' with RSSI -29
Received packet 'Hello NetMF LoRa! -4' with RSSI -29

Next step interrupts for processing inbound messages

.Net MicroFramework LoRa library Part6

Posted on August 19, 2018 by devmobilenz

Receive Basic

I can configure the device to send messages now I need to configure the SX1276 device to receive them. For my first attempt just simple polling for a message to arrive nothing flash.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.ReceiveBasic
{
   using System;
   using System.Text;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public sealed class Rfm9XDevice
   {
      private const byte RegisterAddressReadMask = 0X7f;
      private const byte RegisterAddressWriteMask = 0x80;

      private SPI Rfm9XLoraModem = null;
      private OutputPort ResetGpioPin = null;

      public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin reset)
      {
         // Factory reset pin configuration
         ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
         ResetGpioPin.Write(false);
         Thread.Sleep(10);
         ResetGpioPin.Write(true);
         Thread.Sleep(10);

         this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

         Thread.Sleep(100);
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] writeBuffer = new byte[] { registerAddress };
         byte[] readBuffer = new byte[1];
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);

         return readBuffer[0];
      }

      public ushort RegisterReadWord(byte address)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[2];
         Debug.Assert(Rfm9XLoraModem != null);

         readBuffer[0] = RegisterReadByte(address);
         readBuffer[1] = RegisterReadByte(address += 1);

         return (ushort)(readBuffer[1] + (readBuffer[0] << 8));
      }

      public byte[] RegisterRead(byte address, int length)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[length];
         Debug.Assert(Rfm9XLoraModem != null);

         for (byte index = 0; index < length; index++)
         {
            readBuffer[index] = RegisterReadByte(address += 1);
         }

         return readBuffer;
      }

      public void RegisterWriteByte(byte address, byte value)
      {
         byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterWriteWord(byte address, ushort value)
      {
         byte[] valueBytes = BitConverter.GetBytes(value);
         byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, valueBytes[0], valueBytes[1] };
         Debug.Assert(Rfm9XLoraModem != null);

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterWrite(byte address, byte[] bytes)
      {
         byte[] writeBuffer = new byte[1 + bytes.Length];
         Debug.Assert(Rfm9XLoraModem != null);

         Array.Copy(bytes, 0, writeBuffer, 1, bytes.Length);
         writeBuffer[0] = address |= RegisterAddressWriteMask;

         Rfm9XLoraModem.Write(writeBuffer);
      }

      public void RegisterDump()
      {
         Debug.Print("---Registers 0x00 thru 0x42---");
         for (byte registerIndex = 0; registerIndex  4];

         // Mask off the upper 4 bits to get the rest of it.
         hexString += hexChars[singlebyte & 0x0F];

         return hexString;
      }

      private static string WordToHexString(ushort singleword)
      {
         string hexString = string.Empty;

         byte[] bytes = BitConverter.GetBytes(singleword);

         hexString += ByteToHexString(bytes[1]);

         hexString += ByteToHexString(bytes[0]);

         return hexString;
      }
   }
}

In the debug window I could see messages from one of my arduino devices

The thread '' (0x2) has exited with code 0 (0x0).
Receive-Wait
.
.
.
.
.
.
.

.
.
.
.

Receive-Message
Received 15 byte message HeLoRa World! 0
Receive-Done
Receive-Wait
.
.
.
.
.
.
.
.
.
.
.

Receive-Message
Received 15 byte message HeLoRa World! 2
Receive-Done
Receive-Wait
.
.

Next steps handling inbound & outbound messages with interrupts, then integrating all the samples into a useful functional V1 library.

.Net MicroFramework LoRa library Part5

Posted on August 19, 2018 by devmobilenz

Transmit Basic

Finally at the point where I can send a message to one of my Windows 10 IoT Core devices. Not going to use interrupts, just putting the bytes to send into the SX1276 Fifo and looping until they are sent.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.TransmitBasic
{
   using System;
   using System.Text;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public sealed class Rfm9XDevice
   {
      private const byte RegisterAddressReadMask = 0X7f;
      private const byte RegisterAddressWriteMask = 0x80;

      private SPI Rfm9XLoraModem = null;
      private OutputPort ResetGpioPin = null;

      public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin reset)
      {
         // Factory reset pin configuration
         ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
         ResetGpioPin.Write(false);
         Thread.Sleep(10);
         ResetGpioPin.Write(true);
         Thread.Sleep(10);

         //this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, true, 2000, SPI.SPI_module.SPI1));
         this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

         Thread.Sleep(100);
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] writeBuffer = new byte[] { registerAddress };
         byte[] readBuffer = new byte[1];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);
         Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);

         return readBuffer[0];
      }

      public ushort RegisterReadWord(byte address)
      {
         byte[] writeBuffer = new byte[] { address &amp;= RegisterAddressReadMask };
         byte[] readBuffer = new byte[2];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(readBuffer, writeBuffer, 1 ); // Check this

         readBuffer[0] = RegisterReadByte(address);
         readBuffer[1] = RegisterReadByte(address += 1);

         return (ushort)(readBuffer[1] + (readBuffer[0] &lt;<span id="mce_SELREST_start" style="overflow:hidden;line-height:0;"></span>&lt; 8));
      }

      public byte[] RegisterRead(byte address, int length)
      {
         byte[] writeBuffer = new byte[] { address &amp;= RegisterAddressReadMask };
         byte[] readBuffer = new byte[length];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(readBuffer, writeBuffer, 1); // Check this

         for (byte index = 0; index  4];

         // Mask off the upper 4 bits to get the rest of it.
         hexString += hexChars[singlebyte &amp; 0x0F];

         return hexString;
      }

      private static string WordToHexString(ushort singleword)
      {
         string hexString = string.Empty;

         byte[] bytes = BitConverter.GetBytes(singleword);

         hexString += ByteToHexString(bytes[1]);

         hexString += ByteToHexString(bytes[0]);

         return hexString;
      }

   }
}

The debugging output of the device shows the message being transmitted

The thread '' (0x2) has exited with code 0 (0x0).
Sending 17 bytes message Hello NetMF LoRa!
Send-wait
.
.
.
.
.
Send-Done
Sending 17 bytes message Hello NetMF LoRa!
Send-wait
.
.
.
.
.
Send-Done

On my Windows 10 IoT core device I could see the messages arriving

RegIrqFlags 01010000
Receive-Message
Received 17 byte message Hello NetMF LoRa!
The thread 0x6b4 has exited with code 0 (0x0).
Sending 22 bytes message W10 IoT Core LoRa! 252
RegIrqFlags 00001000
Transmit-Done
RegIrqFlags 01010000
Receive-Message
Received 17 byte message Hello NetMF LoRa!
The program '[2932] backgroundTaskHost.exe' has exited with code -1 (0xffffffff).

All default settings for not a lot of range etc. but it works

.Net MicroFramework LoRa library Part4

Posted on August 18, 2018 by devmobilenz

Register Read and Write

For configuration and operation I extended the RegisterManager class with methods for reading/writing bytes, words and byte arrays.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.RegisterReadandWrite
{
   using System;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public sealed class Rfm9XDevice
   {
      private const byte RegisterAddressReadMask = 0X7f;
      private const byte RegisterAddressWriteMask = 0x80;

      private SPI Rfm9XLoraModem = null;
      private OutputPort ResetGpioPin = null;

      public Rfm9XDevice(Cpu.Pin chipSelect, Cpu.Pin reset)
      {
         // Factory reset pin configuration
         ResetGpioPin = new OutputPort(Pins.GPIO_PIN_D9, true);
         ResetGpioPin.Write(false);
         Thread.Sleep(10);
         ResetGpioPin.Write(true);
         Thread.Sleep(10);

         //this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, true, 2000, SPI.SPI_module.SPI1));
         this.Rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, false, 2000, SPI.SPI_module.SPI1));

         Thread.Sleep(100);
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] writeBuffer = new byte[] { registerAddress };
         byte[] readBuffer = new byte[1];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);
         Rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1 );

         return readBuffer[0];
      }

      public ushort RegisterReadWord(byte address)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[2];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(readBuffer, writeBuffer, 4 ); // Check this

         readBuffer[0] = RegisterReadByte( address ) ;
         readBuffer[1] = RegisterReadByte(address+=1);

         return (ushort)(readBuffer[1] + (readBuffer[0] << 8));
      }

      public byte[] RegisterRead(byte address, int length)
      {
         byte[] writeBuffer = new byte[] { address &= RegisterAddressReadMask };
         byte[] readBuffer = new byte[length];
         Debug.Assert(Rfm9XLoraModem != null);

         //Rfm9XLoraModem.WriteRead(readBuffer, writeBuffer, 1); // Check this

         for (byte index = 0; index  4];

         // Mask off the upper 4 bits to get the rest of it.
         hexString += hexChars[singlebyte & 0x0F];

         return hexString;
      }

      private static string WordToHexString(ushort singleword)
      {
         string hexString = string.Empty;

         byte[] bytes = BitConverter.GetBytes(singleword);

         hexString += ByteToHexString(bytes[1]);

         hexString += ByteToHexString(bytes[0]);

         return hexString;
      }

   }
}

I had to add an extra "ToHexString" method so I could display the returned byte and word values

Read RegOpMode (read byte)
RegOpMode 0x09
Set LoRa mode and sleep mode (write byte)
Read the preamble (read word)
Preamble 0x0008
Set the preamble to 0x80 (write word)
Read the centre frequency (read byte array)
Frequency Msb 0x80 Mid 0x00 Lsb 0x4F
Set the centre frequency to 916MHz (write byte array)
—Registers 0x00 thru 0x42—
Register 0x00 – Value 0XF4
Register 0x01 – Value 0X80
Register 0x02 – Value 0X1A
Register 0x03 – Value 0X0B
Register 0x04 – Value 0X00
Register 0x05 – Value 0X52
Register 0x06 – Value 0XE4
Register 0x07 – Value 0XC0
Register 0x08 – Value 0X00
Register 0x09 – Value 0X4F
Register 0x0A – Value 0X09
Register 0x0B – Value 0X2B
Register 0x0C – Value 0X20
Register 0x0D – Value 0X01
Register 0x0E – Value 0X80
Register 0x0F – Value 0X00
Register 0x10 – Value 0X00
Register 0x11 – Value 0X00
Register 0x12 – Value 0X00
Register 0x13 – Value 0X00
Register 0x14 – Value 0X00
Register 0x15 – Value 0X00
Register 0x16 – Value 0X00
Register 0x17 – Value 0X00
Register 0x18 – Value 0X10
Register 0x19 – Value 0X00
Register 0x1A – Value 0X00
Register 0x1B – Value 0X00
Register 0x1C – Value 0X00
Register 0x1D – Value 0X72
Register 0x1E – Value 0X70
Register 0x1F – Value 0X64
Register 0x20 – Value 0X80
Register 0x21 – Value 0X00
Register 0x22 – Value 0X01
Register 0x23 – Value 0XFF
Register 0x24 – Value 0X00
Register 0x25 – Value 0X00
Register 0x26 – Value 0X04
Register 0x27 – Value 0X00
Register 0x28 – Value 0X00
Register 0x29 – Value 0X00
Register 0x2A – Value 0X00
Register 0x2B – Value 0X00
Register 0x2C – Value 0X00
Register 0x2D – Value 0X50
Register 0x2E – Value 0X14
Register 0x2F – Value 0X45
Register 0x30 – Value 0X55
Register 0x31 – Value 0XC3
Register 0x32 – Value 0X05
Register 0x33 – Value 0X27
Register 0x34 – Value 0X1C
Register 0x35 – Value 0X0A
Register 0x36 – Value 0X03
Register 0x37 – Value 0X0A
Register 0x38 – Value 0X42
Register 0x39 – Value 0X12
Register 0x3A – Value 0X49
Register 0x3B – Value 0X1D
Register 0x3C – Value 0X00
Register 0x3D – Value 0XAF
Register 0x3E – Value 0X00
Register 0x3F – Value 0X00
Register 0x40 – Value 0X00
Register 0x41 – Value 0X00
Register 0x42 – Value 0X12

The register dump shows the SX1276 is in LoRa+Sleep mode and the preamble is set to 0x80 etc.

The way I read words and arrays of bytes isn’t very efficient will need to revisit when I have more time and/or access to a digital storage scope.

.Net MicroFramework LoRa library Part3

Posted on August 18, 2018 by devmobilenz

Register Scan

Next step was to scan the Semtech SX127X registers and check the values were as expected

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.RegisterScan
{
   using System;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public sealed class Rfm9XDevice
   {
      private SPI rfm9XLoraModem = null;

      public Rfm9XDevice(Cpu.Pin chipSelect)
      {
         this.rfm9XLoraModem = new SPI(new SPI.Configuration(chipSelect, false, 0, 0, false, true, 500, SPI.SPI_module.SPI1));

         Thread.Sleep(100);
      }

      public Byte RegisterReadByte(byte registerAddress)
      {
         byte[] writeBuffer = new byte[] { registerAddress };
         byte[] readBuffer = new byte[1];
         Debug.Assert(rfm9XLoraModem != null);

         rfm9XLoraModem.WriteRead(writeBuffer, readBuffer, 1);

         return readBuffer[0];
      }
   }

   public class Program
   {
      public static void Main()
      {
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(Pins.GPIO_PIN_D10);

         while (true)
         {
            Debug.Print("---Registers 0x00 thru 0x42---");
            for (byte registerIndex = 0; registerIndex > 4];

         // Mask off the upper 4 bits to get the rest of it.
         hexString += hexChars[singlebyte & 0x0F];

         return hexString;
      }
   }
}

On start-up the device is not in LoRa mode so some weren’t set up properly.

---Registers 0x00 thru 0x42---
Register 0x00 - Value 0X00
Register 0x01 - Value 0X09
Register 0x02 - Value 0X1A
Register 0x03 - Value 0X0B
Register 0x04 - Value 0X00
Register 0x05 - Value 0X52
Register 0x06 - Value 0X6C
Register 0x07 - Value 0X80
Register 0x08 - Value 0X00
Register 0x09 - Value 0X4F
Register 0x0A - Value 0X09
Register 0x0B - Value 0X2B
Register 0x0C - Value 0X20
Register 0x0D - Value 0X08
Register 0x0E - Value 0X02
Register 0x0F - Value 0X0A
Register 0x10 - Value 0XFF
Register 0x11 - Value 0X70
Register 0x12 - Value 0X15
Register 0x13 - Value 0X0B
Register 0x14 - Value 0X28
Register 0x15 - Value 0X0C
Register 0x16 - Value 0X12
Register 0x17 - Value 0X47
Register 0x18 - Value 0X32
Register 0x19 - Value 0X3E
Register 0x1A - Value 0X00
Register 0x1B - Value 0X00
Register 0x1C - Value 0X00
Register 0x1D - Value 0X00
Register 0x1E - Value 0X00
Register 0x1F - Value 0X40
Register 0x20 - Value 0X00
Register 0x21 - Value 0X00
Register 0x22 - Value 0X00
Register 0x23 - Value 0X00
Register 0x24 - Value 0X05
Register 0x25 - Value 0X00
Register 0x26 - Value 0X03
Register 0x27 - Value 0X93
Register 0x28 - Value 0X55
Register 0x29 - Value 0X55
Register 0x2A - Value 0X55
Register 0x2B - Value 0X55
Register 0x2C - Value 0X55
Register 0x2D - Value 0X55
Register 0x2E - Value 0X55
Register 0x2F - Value 0X55
Register 0x30 - Value 0X90
Register 0x31 - Value 0X40
Register 0x32 - Value 0X40
Register 0x33 - Value 0X00
Register 0x34 - Value 0X00
Register 0x35 - Value 0X0F
Register 0x36 - Value 0X00
Register 0x37 - Value 0X00
Register 0x38 - Value 0X00
Register 0x39 - Value 0XF5
Register 0x3A - Value 0X20
Register 0x3B - Value 0X82
Register 0x3C - Value 0X00
Register 0x3D - Value 0X02
Register 0x3E - Value 0X80
Register 0x3F - Value 0X40
Register 0x40 - Value 0X00
Register 0x41 - Value 0X00
Register 0x42 - Value 0X12

Next step reading & writing registers

.Net MicroFramework LoRa library Part2

Posted on August 17, 2018 by devmobilenz

Register Read

Getting this bit too work took a bit longer than expected. The code below works but isn’t super efficient. I must be reading the SX1276 SPI timing diagram wrong or I need to read the .NetMF SPI implementation code some more.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.RegisterRead
{
   using System;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public class Program
   {

      public static void Main()
      {
         //OutputPort reset = new OutputPort(Pins.GPIO_PIN_D9, true);
         OutputPort chipSelect = null;
         //chipSelect = new OutputPort(Pins.GPIO_PIN_D10, true);
         //SPI spiPort = new SPI(new SPI.Configuration(Pins.GPIO_NONE, false, 0, 0, true, true, 500, SPI.SPI_module.SPI1));
         SPI spiPort = new SPI(new SPI.Configuration(Pins.GPIO_PIN_D10, false, 0, 0, false, true, 500, SPI.SPI_module.SPI1));

         Thread.Sleep(100);

         while (true)
         {
            //byte[] writeBuffer = new byte[] { 0x42 }; // RegVersion exptecing 0x12
            byte[] writeBuffer = new byte[] { 0x06 }; // RegFreqMsb expecting 0x6C
            //byte[] writeBuffer = new byte[] { 0x07 }; // RegFreqMid expecting 0x80
            //byte[] writeBuffer = new byte[] { 0x08 }; // RegFreqLsb expecting 0x00
            byte[] readBuffer = new byte[1];

            if (chipSelect != null)
            {
               chipSelect.Write(false);
            }
            spiPort.WriteRead(writeBuffer, readBuffer, 1);
            if (chipSelect != null)
            {
               chipSelect.Write(true);
            }

            Debug.Print("Value = 0x" + BytesToHexString(readBuffer));

            Thread.Sleep(1000);
         }
      }

      private static string BytesToHexString(byte[] bytes)
      {
         string hexString = string.Empty;

         // Create a character array for hexidecimal conversion.
         const string hexChars = "0123456789ABCDEF";

         // Loop through the bytes.
         for (byte b = 0; b  0)
               hexString += "-";

            // Grab the top 4 bits and append the hex equivalent to the return string.
            hexString += hexChars[bytes[b] >> 4];

            // Mask off the upper 4 bits to get the rest of it.
            hexString += hexChars[bytes[b] & 0x0F];
         }

         return hexString;
      }
   }
}

The output indicated that I could success fully read the middle byte (of three) of the transmit frequency and it matched the default. There seems to be something odd about the chip select line/ sequencing

The thread '' (0x2) has exited with code 0 (0x0).
Value = 0xE4
Value = 0xE4
Value = 0xE4
Value = 0xE4
Value = 0xE4
Value = 0xE4

It’s late, so the next step will be scanning the SX1276 registers and starting to build out the register manager code to read+write byte values, word values and arrays.

Also noticed that setup seems to work a bit better on a Netduino3 device, have noticed this before with higher power consumption shields.

.Net MicroFramework LoRa library Part1

Posted on August 16, 2018 by devmobilenz

After getting my Windows 10 IoT Core RFM9X library well under way I figured that writing a library for .NetMF devices (like Netduino and Ingenuity Micro ones) shouldn’t be “rocket science”.

To get started I used a Dragino LoRa shield for Arduino which looked compatible with my Netduino devices. I was initially worried that the shield might not work with a 3v3 device but I tested it with a Seeeduino Lite (which has a switch to select 3v3 or 5v operation) and it worked fine.

The shield uses D10 for chip select, D2 for RFM9X DI0 interrupt and D9 for Reset.
Lora_sheild_sch
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.
NetduinoDraginoShield
First step was to confirm I could (using the Netduino SPI interface and .NetMF library)read a couple of the Semtech SX1276 registers. I implemented both “automagic” and manual chip select operation in my test harness.

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, 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.NetMF.Rfm9X.DraginoShield
{
   using System;
   using System.Threading;
   using Microsoft.SPOT;
   using Microsoft.SPOT.Hardware;
   using SecretLabs.NETMF.Hardware;
   using SecretLabs.NETMF.Hardware.Netduino;

   public class Program
   {

      public static void Main()
      {
         //OutputPort reset = new OutputPort(Pins.GPIO_PIN_D9, true);
         OutputPort chipSelect = null;
         //chipSelect = new OutputPort(Pins.GPIO_PIN_D10, true);
         //SPI spiPort = new SPI(new SPI.Configuration(Pins.GPIO_NONE, false, 0, 0, true, true, 500, SPI.SPI_module.SPI1));
         SPI spiPort = new SPI(new SPI.Configuration(Pins.GPIO_PIN_D10, false, 0, 0, false, true, 500, SPI.SPI_module.SPI1));

         Thread.Sleep(100);

         while (true)
         {
            //byte[] writeBuffer = new byte[] { 0x42 }; // RegVersion exptecing 0x12
            byte[] writeBuffer = new byte[] { 0x06 }; // RegFreqMsb expecting 0x6C
            //byte[] writeBuffer = new byte[] { 0x07 }; // RegFreqMid expecting 0x80
            //byte[] writeBuffer = new byte[] { 0x08 }; // RegFreqLsb expecting 0x00
            byte[] readBuffer = new byte[1];

            if (chipSelect != null)
            {
               chipSelect.Write(false);
            }
            spiPort.WriteRead(writeBuffer, readBuffer,1);
            if (chipSelect != null)
            {
               chipSelect.Write(true);
            }

            Debug.Print("Value = 0x" + BytesToHexString(readBuffer));

            Thread.Sleep(1000);
         }
      }

      private static string BytesToHexString(byte[] bytes)
      {
         string hexString = string.Empty;

         // Create a character array for hexidecimal conversion.
         const string hexChars = "0123456789ABCDEF";

         // Loop through the bytes.
         for (byte b = 0; b  0)
               hexString += "-";

            // Grab the top 4 bits and append the hex equivalent to the return string.
            hexString += hexChars[bytes[b] >> 4];

            // Mask off the upper 4 bits to get the rest of it.
            hexString += hexChars[bytes[b] & 0x0F];
         }

         return hexString;
      }
   }
}

I could successfully read the RegVersion and default frequency values

'Microsoft.SPOT.Debugger.CorDebug.dll' (Managed): Loaded 'C:\Program Files (x86)\Secret Labs\Netduino SDK\Assemblies\v4.3\le\SecretLabs.NETMF.Hardware.dll', Symbols loaded.
The thread '' (0x2) has exited with code 0 (0x0).
Value = 0x6C
Value = 0x6C
Value = 0x6C
The program '[43] Micro Framework application: Managed' has exited with code 0 (0x0).

Netduino 3 AnalogInput read rates

Posted on November 5, 2015 by devmobilenz

At CodeClub some of the students build a power consumption meter and as part of that project we measure the AnalogInput sample rates to check they are sufficient for our application.

Earlier this term when we measured the sampling rates in a CodeClub session we had a mix of Netduino 2 and Netduino 3 devices and some of the results differed from my previous observations. I used the same code on all the devices

int value;
AnalogInput x1 = new AnalogInput(Cpu.AnalogChannel.ANALOG_0);
stopwatch.Start();
for (int i = 0; i < SampleCount; i++)
{
value = x1.ReadRaw();
}
stopwatch.Stop();

Netduino Plus 2

Duration = 2081 mSec 48053/sec
Duration = 2082 mSec 48030/sec
Duration = 2081 mSec 48053/sec
Duration = 2081 mSec 48053/sec
Duration = 2082 mSec 48030/sec
Duration = 2081 mSec 48053/sec
Duration = 2081 mSec 48053/sec
Duration = 2081 mSec 48053/sec
Duration = 2081 mSec 48053/sec
Duration = 2081 mSec 48053/sec

Netduino 3

Duration = 2071 mSec 48285/sec
Duration = 2069 mSec 48332/sec
Duration = 2070 mSec 48309/sec
Duration = 2071 mSec 48285/sec
Duration = 2071 mSec 48285/sec
Duration = 2070 mSec 48309/sec
Duration = 2070 mSec 48309/sec
Duration = 2071 mSec 48285/sec
Duration = 2071 mSec 48285/sec
Duration = 2071 mSec 48285/sec

Netduino 3 Ethernet
Duration = 2136 mSec 46816/sec
Duration = 2137 mSec 46794/sec
Duration = 2136 mSec 46816/sec
Duration = 2135 mSec 46838/sec
Duration = 2135 mSec 46838/sec
Duration = 2137 mSec 46794/sec
Duration = 2137 mSec 46794/sec
Duration = 2135 mSec 46838/sec
Duration = 2136 mSec 46816/sec
Duration = 2135 mSec 46838/sec

Netduino 3 Wifii
Duration = 3902 mSec 25627/sec
Duration = 3901 mSec 25634/sec
Duration = 3902 mSec 25627/sec
Duration = 3902 mSec 25627/sec
Duration = 3901 mSec 25634/sec
Duration = 3903 mSec 25621/sec
Duration = 3903 mSec 25621/sec
Duration = 3902 mSec 25627/sec
Duration = 3902 mSec 25627/sec
Duration = 3903 mSec 25621/sec

The results for the Netduino 3 & Netduino 3 Ethernet were comparable with the Netduino Plus 2 in my earlier post. The reduction in the sampling rate of the Netduino 3 Wifi warrants some further investigation.

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