netMF Electric Longboard Part 2

Analog Inputs & Pulse Width Modulation

The next step was to figure out how to configure a Pulse Width Modulation (PWM) output and an Analog Input so I could adjust the duty cycle and control the brightness of a Light Emitting Diode(LED).

Netduino 3 ADC & PWN test rig

My test rig uses (prices as at Aug 2020) the following parts

  • Netduino 3 Wifi
  • Grove-Base Shield V2.0 for Arduino USD4.45
  • Grove-Universal 4 Pin Bucked 5cm cable(5 PCs Pack) USD1.90
  • Grove-Universal 4 Pin Bucked 20cm cable(5 PCs Pack) USD2.90
  • Grove-LED Pack USD2.90
  • Grove-Rotary Angle Sensor USD2.90

My analog input test harness

 public class Program
   {
      public static void Main()
      {
         Debug.WriteLine("devMobile.Longboard.AdcTest starting");
         Debug.WriteLine(AdcController.GetDeviceSelector());

         try
         {
            AdcController adc = AdcController.GetDefault();
            AdcChannel adcChannel = adc.OpenChannel(0);

            while (true)
            {
               double value = adcChannel.ReadRatio();

               Debug.WriteLine($"Value: {value:F2}");

               Thread.Sleep(100);
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);
         }
      }
   }

The nanoFramework code polls for the rotary angle sensor for its position value every 100mSec.

The setup to use for the Analog to Digital Convertor(ADC) port was determined by looking at the board.h and target_windows_devices_adc_config.cpp file.

//
// Copyright (c) 2018 The nanoFramework project contributors
// See LICENSE file in the project root for full license information.
//

#include <win_dev_adc_native_target.h>

const NF_PAL_ADC_PORT_PIN_CHANNEL AdcPortPinConfig[] = {
    
    // ADC1
    {1, GPIOC, 0, ADC_CHANNEL_IN10},
    {1, GPIOC, 1, ADC_CHANNEL_IN11},

    // ADC2
    {2, GPIOC, 2, ADC_CHANNEL_IN14},
    {2, GPIOC, 3, ADC_CHANNEL_IN15},

    // ADC3
    {3, GPIOC, 4, ADC_CHANNEL_IN12},
    {3, GPIOC, 5, ADC_CHANNEL_IN13},

    // these are the internal sources, available only at ADC1
    {1, NULL, 0, ADC_CHANNEL_SENSOR},
    {1, NULL, 0, ADC_CHANNEL_VREFINT},
    {1, NULL, 0, ADC_CHANNEL_VBAT},
};

const int AdcChannelCount = ARRAYSIZE(AdcPortPinConfig);

The call to AdcController.GetDeviceSelector() only returned one controller

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.Longboard.AdcTest starting
ADC1

After some experimentation it appears that only A0 & A1 work on a Netduino. (Aug 2020).

My PWM test harness

public class Program
{
   public static void Main()
   {
      Debug.WriteLine("devMobile.Longboard.PwmTest starting");
      Debug.WriteLine(PwmController.GetDeviceSelector());

      try
      {
         PwmController pwm = PwmController.FromId("TIM5");
         AdcController adc = AdcController.GetDefault();
         AdcChannel adcChannel = adc.OpenChannel(0);

         PwmPin pwmPin = pwm.OpenPin(PinNumber('A', 0));
         pwmPin.Controller.SetDesiredFrequency(1000);
         pwmPin.Start();

         while (true)
         {
            double value = adcChannel.ReadRatio();

            Debug.WriteLine(value.ToString("F2"));

            pwmPin.SetActiveDutyCyclePercentage(value);

            Thread.Sleep(100);
         }
      }
      catch (Exception ex)
      {
         Debug.WriteLine(ex.Message);
      }
   }

   private static int PinNumber(char port, byte pin)
   {
      if (port < 'A' || port > 'J')
         throw new ArgumentException();
      return ((port - 'A') * 16) + pin;
   }
}

I had to refer to the Netduino schematic to figure out pin mapping

With my test rig (with easy access to D0 to D8)I found that only D2,D3,D7 and D8 worked as PWM outputs.

The next test rig will be getting Servo working.

netMF Electric Longboard Part 1

Wiichuck connectivity

Roughly four years ago I build myself an electric longboard as summer transport. It initially had a controller built with a devDuino V2.2 which after a while I “upgraded” to a GHI Electronics .NET Microframework device.

Configuring the original netMF based longboard

Now that GHI Electronics no longer supports the FEZ Panda III I figured upgrading to a device that runs the nanoFramework would be a good compromise.

I control the speed of the longboard with a generic wireless wii nunchuk. So my first project is porting the .NET Micro Framework Toolbox code to the nanoFramework.

wireless controller test rig

My test rig uses (prices as at Aug 2020) the following parts

  • Netduino 3 Wifi
  • Grove-Base Shield V2.0 for Arduino USD4.45
  • Grove-Universal 4 Pin Bucked 5cm cable(5 PCs Pack) USD1.90
  • Grove-Nunchuck USD2.90
  • Generic wireless WII nunchuk

My changes were mainly related to the Inter Integrated Circuit(I2C) configuration and the reading+writing of registers.

/// <summary>
/// Initialises a new Wii Nunchuk
/// </summary>
/// <param name="busId">The unique identifier of the I²C to use.</param>
/// <param name="slaveAddress">The I²C address</param>
/// <param name="busSpeed">The bus speed, an enumeration that defaults to StandardMode</param>
/// <param name="sharingMode">The sharing mode, an enumeration that defaults to Shared.</param>
public WiiNunchuk(string busId, ushort slaveAddress = 0x52, I2cBusSpeed busSpeed = I2cBusSpeed.StandardMode, I2cSharingMode sharingMode = I2cSharingMode.Shared)
   {
      I2cTransferResult result;

      // This initialisation routine seems to work. I got it at http://wiibrew.org/wiki/Wiimote/Extension_Controllers#The_New_Way
      Device = I2cDevice.FromId(busId, new I2cConnectionSettings(slaveAddress)
      {
         BusSpeed = busSpeed,
         SharingMode = sharingMode,
      });

      result = Device.WritePartial(new byte[] { 0xf0, 0x55 });
      if (result.Status != I2cTransferStatus.FullTransfer)
      {
         throw new ApplicationException("Something went wrong reading the Nunchuk. Did you use proper pull-up resistors?");
      }

      result = Device.WritePartial(new byte[] { 0xfb, 0x00 });
      if (result.Status != I2cTransferStatus.FullTransfer)
      {
         throw new ApplicationException("Something went wrong reading the Nunchuk. Did you use proper pull-up resistors?");
      }

      this.Device.Write(new byte[] { 0xf0, 0x55 });
      this.Device.Write(new byte[] { 0xfb, 0x00 });
   }

   /// <summary>
   /// Reads all data from the nunchuk
   /// </summary>
   public void Read()
   {
      byte[] WaitWriteBuffer = { 0 };
      I2cTransferResult result;

      result = Device.WritePartial(WaitWriteBuffer);
      if (result.Status != I2cTransferStatus.FullTransfer)
      {
         throw new ApplicationException("Something went wrong reading the Nunchuk. Did you use proper pull-up resistors?");
      }

      byte[] ReadBuffer = new byte[6];
      result = Device.ReadPartial(ReadBuffer);
      if (result.Status != I2cTransferStatus.FullTransfer)
      {
         throw new ApplicationException("Something went wrong reading the Nunchuk. Did you use proper pull-up resistors?");
      }

      // Parses data according to http://wiibrew.org/wiki/Wiimote/Extension_Controllers/Nunchuck#Data_Format

      // Analog stick
      this.AnalogStickX = ReadBuffer[0];
      this.AnalogStickY = ReadBuffer[1];

      // Accelerometer
      ushort AX = (ushort)(ReadBuffer[2] << 2);
      ushort AY = (ushort)(ReadBuffer[3] << 2);
      ushort AZ = (ushort)(ReadBuffer[4] << 2);
      AZ += (ushort)((ReadBuffer[5] & 0xc0) >> 6); // 0xc0 = 11000000
      AY += (ushort)((ReadBuffer[5] & 0x30) >> 4); // 0x30 = 00110000
      AX += (ushort)((ReadBuffer[5] & 0x0c) >> 2); // 0x0c = 00001100
      this.AcceleroMeterX = AX;
      this.AcceleroMeterY = AY;
      this.AcceleroMeterZ = AZ;

      // Buttons
      ButtonC = (ReadBuffer[5] & 0x02) != 0x02;    // 0x02 = 00000010
      ButtonZ = (ReadBuffer[5] & 0x01) != 0x01;    // 0x01 = 00000001
}

The nanoFramework code polls for the joystick position and accelerometer values every 100mSec

public class Program
{
   public static void Main()
   {
      Debug.WriteLine("devMobile.Longboard.WiiNunchuckTest starting");
      Debug.WriteLine(I2cDevice.GetDeviceSelector());

      try
      {
         WiiNunchuk nunchuk = new WiiNunchuk("I2C1");

         while (true)
         {
            nunchuk.Read();

            Debug.WriteLine($"JoyX: {nunchuk.AnalogStickX} JoyY:{nunchuk.AnalogStickY} AX:{nunchuk.AcceleroMeterX} AY:{nunchuk.AcceleroMeterY} AZ:{nunchuk.AcceleroMeterZ} BtnC:{nunchuk.ButtonC} BtnZ:{nunchuk.ButtonZ}");

            Thread.Sleep(100);
         }
      }
      catch (Exception ex)
      {
         Debug.WriteLine(ex.Message);
      }
   }
}

The setup to use for the I2C port was determined by looking at the board.h and target_windows_devices_I2C_config.cpp file

//
// Copyright (c) 2018 The nanoFramework project contributors
// See LICENSE file in the project root for full license information.
//

#include <win_dev_i2c_native_target.h>

//////////
// I2C1 //
//////////

// pin configuration for I2C1
// port for SCL pin is: GPIOB
// port for SDA pin is: GPIOB
// SCL pin: is GPIOB_6
// SDA pin: is GPIOB_7
// GPIO alternate pin function is 4 (see alternate function mapping table in device datasheet)
I2C_CONFIG_PINS(1, GPIOB, GPIOB, 6, 7, 4)

Then checking this against the Netduino 3 Wifi schematic.

This image has an empty alt attribute; its file name is netduinoschematic-1.jpg

After some experimentation with how to detect if an I2C read or write had failed the debugging console output began displaying reasonable value

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
devMobile.Longboard.WiiNunchuckTest starting
I2C1
JoyX: 128 JoyY:128 AX:520 AY:508 AZ:708 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:520 AY:504 AZ:716 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:524 AY:508 AZ:716 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:524 AY:536 AZ:708 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:516 AY:528 AZ:724 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:492 AY:524 AZ:720 BtnC:True BtnZ:False
JoyX: 128 JoyY:128 AX:508 AY:528 AZ:700 BtnC:True BtnZ:False
JoyX: 128 JoyY:128 AX:504 AY:532 AZ:716 BtnC:True BtnZ:False
JoyX: 128 JoyY:128 AX:512 AY:532 AZ:724 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:516 AY:532 AZ:712 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:520 AY:532 AZ:708 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:524 AY:532 AZ:708 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:480 AY:504 AZ:688 BtnC:True BtnZ:True
JoyX: 128 JoyY:128 AX:480 AY:520 AZ:728 BtnC:False BtnZ:True
JoyX: 128 JoyY:128 AX:512 AY:520 AZ:704 BtnC:False BtnZ:True
JoyX: 128 JoyY:128 AX:512 AY:548 AZ:708 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:504 AY:516 AZ:728 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:548 AY:536 AZ:704 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:500 AY:528 AZ:728 BtnC:True BtnZ:False
JoyX: 128 JoyY:128 AX:496 AY:524 AZ:716 BtnC:True BtnZ:False
JoyX: 128 JoyY:128 AX:528 AY:536 AZ:696 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:540 AY:540 AZ:720 BtnC:False BtnZ:False
JoyX: 128 JoyY:128 AX:500 AY:520 AZ:684 BtnC:False BtnZ:False
JoyX: 128 JoyY:0 AX:520 AY:508 AZ:696 BtnC:False BtnZ:False
JoyX: 29 JoyY:0 AX:488 AY:576 AZ:716 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:532 AY:540 AZ:700 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:492 AY:512 AZ:708 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:492 AY:516 AZ:708 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:504 AY:512 AZ:708 BtnC:False BtnZ:False
JoyX: 27 JoyY:128 AX:508 AY:520 AZ:700 BtnC:False BtnZ:False
JoyX: 106 JoyY:128 AX:504 AY:516 AZ:700 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:496 AY:520 AZ:700 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:512 AY:532 AZ:716 BtnC:False BtnZ:False
JoyX: 0 JoyY:128 AX:500 AY:516 AZ:708 BtnC:False BtnZ:False
JoyX: 85 JoyY:113 AX:500 AY:536 AZ:720 BtnC:False BtnZ:False
JoyX: 128 JoyY:110 AX:512 AY:532 AZ:712 BtnC:False BtnZ:False
JoyX: 128 JoyY:90 AX:516 AY:528 AZ:716 BtnC:False BtnZ:False
JoyX: 128 JoyY:43 AX:508 AY:468 AZ:660 BtnC:False BtnZ:False
JoyX: 128 JoyY:0 AX:508 AY:532 AZ:712 BtnC:False BtnZ:False
JoyX: 128 JoyY:0 AX:496 AY:524 AZ:716 BtnC:False BtnZ:False

The next test rig will be getting Pulse Width Modulation(PWM) working.

nanoFramework nRF24L01 library Part1

After porting then debugging Windows 10 IoT Core, .NetMF, Wilderness Labs Meadow and GHI Electronics TinyCLR nRF24L01P libraries I figured yet another port, this time to a nanoFramework powered devices should be low risk.

My initial test rig uses a Netduino 3 Wifi and an Embedded Coolness nRF24 shield as I didn’t need to use jumper wires.

//---------------------------------------------------------------------------------
// Copyright (c) July 2020, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
#define NETDUINO3_WIFI   // nanoff --target NETDUINO3_WIFI --update

namespace devMobile.IoT.nRf24L01.ModuleSPI
{
   using System;
   using System.Threading;
   using System.Diagnostics;
   using System.Text;
   using Windows.Devices.Gpio;
   using Windows.Devices.Spi;

   public class Program
   {
      const byte SETUP_AW = 0x03;
      const byte RF_CH = 0x05;
      const byte RX_ADDR_P0 = 0x0A;
      const byte R_REGISTER = 0b00000000;
      const byte W_REGISTER = 0b00100000;
      const string P0_Address = "ZYXWV";

#if NETDUINO3_WIFI
      private const string SpiBusId = "SPI2";
#endif

      public static void Main()
      {
#if NETDUINO3_WIFI
         // Arduino D7->PD7
         int chipSelectPinNumber = PinNumber('A', 1);
#endif
         Debug.WriteLine("devMobile.IoT.nRf24L01.ModuleSPI starting");

         Debug.WriteLine(Windows.Devices.Spi.SpiDevice.GetDeviceSelector());

         try
         {
            GpioController gpioController = GpioController.GetDefault();

            var settings = new SpiConnectionSettings(chipSelectPinNumber)
            {
               ClockFrequency = 2000000,
               Mode = SpiMode.Mode0,
               SharingMode = SpiSharingMode.Shared,
            };

            using (SpiDevice device = SpiDevice.FromId(SpiBusId, settings))
            {
               Debug.WriteLine("nrf24L01Device Device...");
               if (device == null)
               {
                  Debug.WriteLine("nrf24L01Device == null");
               }

               Thread.Sleep(100);

               Debug.WriteLine("ConfigureSpiPort Done...");
               Debug.WriteLine("");

               Thread.Sleep(500);
               try
               {
                  // Read the Address width
                  Debug.WriteLine("Read address width");
                  byte[] txBuffer1 = new byte[] { SETUP_AW | R_REGISTER, 0x0 };
                  byte[] rxBuffer1 = new byte[txBuffer1.Length];

                  Debug.WriteLine(" nrf24L01Device.TransferFullDuplex...SETUP_AW");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer1));
                  device.TransferFullDuplex(txBuffer1, rxBuffer1);
                  Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer1));

                  // Extract then adjust the address width
                  byte addressWidthValue = rxBuffer1[1];
                  addressWidthValue &= 0b00000011;
                  addressWidthValue += 2;
                  Debug.WriteLine($"Address width 0x{SETUP_AW:x2} - Value 0X{rxBuffer1[1]:x2} Value adjusted {addressWidthValue}");
                  Debug.WriteLine("");

                  // Write Pipe0 Receive address
                  Debug.WriteLine($"Write Pipe0 Receive Address {P0_Address}");
                  byte[] txBuffer2 = new byte[addressWidthValue + 1];
                  byte[] rxBuffer2 = new byte[txBuffer2.Length];
                  txBuffer2[0] = RX_ADDR_P0 | W_REGISTER;
                  Array.Copy(Encoding.UTF8.GetBytes(P0_Address), 0, txBuffer2, 1, addressWidthValue);

                  Debug.WriteLine(" nrf24L01Device.Write...RX_ADDR_P0");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer2));
                  device.TransferFullDuplex(txBuffer2, rxBuffer2);
                  Debug.WriteLine("");

                  // Read Pipe0 Receive address
                  Debug.WriteLine("Read Pipe0 Receive address");
                  byte[] txBuffer3 = new byte[addressWidthValue + 1];
                  txBuffer3[0] = RX_ADDR_P0 | R_REGISTER;
                  byte[] rxBuffer3 = new byte[txBuffer3.Length];

                  Debug.WriteLine(" nrf24L01Device.TransferFullDuplex...RX_ADDR_P0");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer3));
                  device.TransferFullDuplex(txBuffer3, rxBuffer3);
                  Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer3));
                  Debug.WriteLine($"Address 0x{RX_ADDR_P0:x2} Address {UTF8Encoding.UTF8.GetString(rxBuffer3, 1, addressWidthValue)}");
                  Debug.WriteLine("");

                  // Read the RF Channel
                  Debug.WriteLine("RF Channel read 1");
                  byte[] txBuffer4 = new byte[] { RF_CH | R_REGISTER, 0x0 };
                  byte[] rxBuffer4 = new byte[txBuffer4.Length];

                  Debug.WriteLine(" nrf24L01Device.TransferFullDuplex...RF_CH");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer4));
                  device.TransferFullDuplex(txBuffer4, rxBuffer4);
                  Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer4));

                  byte rfChannel1 = rxBuffer4[1];
                  Debug.WriteLine($"RF Channel 1 0x{RF_CH:x2} - Value 0X{rxBuffer4[1]:x2} - Value adjusted {rfChannel1+2400}");
                  Debug.WriteLine("");

                  // Write the RF Channel
                  Debug.WriteLine("RF Channel write");
                  byte[] txBuffer5 = new byte[] { RF_CH | W_REGISTER, rfChannel1+=1};
                  byte[] rxBuffer5 = new byte[txBuffer5.Length];

                  Debug.WriteLine(" nrf24L01Device.Write...RF_CH");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer5));
                  //device.Write(txBuffer5);
                  device.TransferFullDuplex(txBuffer5, rxBuffer5);
                  Debug.WriteLine("");

                  // Read the RF Channel
                  Debug.WriteLine("RF Channel read 2");
                  byte[] txBuffer6 = new byte[] { RF_CH | R_REGISTER, 0x0 };
                  byte[] rxBuffer6 = new byte[txBuffer6.Length];

                  Debug.WriteLine(" nrf24L01Device.TransferFullDuplex...RF_CH");
                  Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer6));
                  device.TransferFullDuplex(txBuffer6, rxBuffer6);
                  Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer6));

                  byte rfChannel2 = rxBuffer6[1];
                  Debug.WriteLine($"RF Channel 2 0x{RF_CH:x2} - Value 0X{rxBuffer6[1]:x2} - Value adjusted {rfChannel2+2400}");
                  Debug.WriteLine("");
               }
               catch (Exception ex)
               {
                  Debug.WriteLine("Configure Port0 " + ex.Message);
               }
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);
         }
      }

#if NETDUINO3_WIFI
      static int PinNumber(char port, byte pin)
      {
         if (port < 'A' || port > 'J')
            throw new ArgumentException();

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

After bit of tinkering with SPI configuration options and checking device.Write vs. device.TransferFullDuplex usage. I can reliably read and write my nRF24L01 device’s receive port address and channel configuration.

devMobile.IoT.nRf24L01.ModuleSPI starting
SPI1,SPI2,SPI3,SPI4
nrf24L01Device Device...
ConfigureSpiPort Done...

Read address width
 nrf24L01Device.TransferFullDuplex...SETUP_AW
 txBuffer:03-00
 rxBuffer:0E-03
Address width 0x03 - Value 0X03 Value adjusted 5

Write Pipe0 Receive Address ZYXWV
 nrf24L01Device.Write...RX_ADDR_P0
 txBuffer:2A-5A-59-58-57-56

Read Pipe0 Receive address
 nrf24L01Device.TransferFullDuplex...RX_ADDR_P0
 txBuffer:0A-00-00-00-00-00
 rxBuffer:0E-5A-59-58-57-56
Address 0x0A Address ZYXWV

RF Channel read 1
 nrf24L01Device.TransferFullDuplex...RF_CH
 txBuffer:05-00
 rxBuffer:0E-02
RF Channel 1 0x05 - Value 0X02 - Value adjusted 2402

RF Channel write
 nrf24L01Device.Write...RF_CH
 txBuffer:25-03

RF Channel read 2
 nrf24L01Device.TransferFullDuplex...RF_CH
 txBuffer:05-00
 rxBuffer:0E-03
RF Channel 2 0x05 - Value 0X03 - Value adjusted 2403

The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Done.

Next step is to port my TinyCLR nRF24L01 library which is based on the Techfoonina Windows 10 IoT Core port which is based on .NetMF library by Gralin.

nanoFramework RAK811 LoRaWAN library Part7

Now with added callbacks

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

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

STM32F691Discovery with EVB plugged into Arduino headers

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

//---------------------------------------------------------------------------------
// Copyright (c) June 2020, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
#define ST_STM32F769I_DISCOVERY      // nanoff --target ST_STM32F769I_DISCOVERY --update 
#define PAYLOAD_BCD
//#define PAYLOAD_BYTES
#define OTAA
//#define ABP
#define CONFIRMED
namespace devMobile.IoT.Rak811LoRaWanDeviceClient
{
   using System;
   using System.Threading;
   using System.Diagnostics;
   using Windows.Devices.SerialCommunication;

   using devMobile.IoT.LoRaWan;

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

      public static void Main()
      {
         Result result;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The debugging output with the Rak811LoRaWanDevice class diagnostics off

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

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

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

nanoFramework RAK811 LoRaWAN library Part6

Inspired by the Arduino Library

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

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

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

STM32F691Discovery with EVB plugged into Arduino headers

The code application code is now a lot smaller & simpler

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

      public static void Main()
      {
         Result result;

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

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

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

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

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

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

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

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

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

                  Thread.Sleep(20000);

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

I compared the debugging output with confirmations off

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

nanoFramework RAK811 LoRaWAN library Part5

Nasty ABP connect

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

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

STM32F691Discovery with EVB plugged into Arduino headers

I created a new ABP device

Things Network ABP configuration

Then I configured the RAK811 module for LoRaWAN

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

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

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

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

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

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

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

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

ABP Device data uplink

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

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

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

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

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

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

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

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

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

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

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

nanoFramework RAK811 LoRaWAN library Part4

Nasty OTAA connect

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

STM32F691Discovery with EVB plugged into Arduino headers

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

I configured the RAK811 module for LoRaWAN

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Confirmed messages
Unconfirmed messages

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

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

nanoFramework RAK811 LoRaWAN library Part3

Factory Reset

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

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

//---------------------------------------------------------------------------------
// Copyright (c) June 2020, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
// nanoff --target ST_STM32F769I_DISCOVERY --update
//#define SERIAL_SYNC_READ
//#define HARDWARE_RESET
//#define SOFTWARE_RESTART
//#define DEVICE_STATUS
//#define LORA_STATUS
namespace devMobile.IoT.Rak811.FactoryReset
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using Windows.Devices.Gpio;
   using Windows.Devices.SerialCommunication;
   using Windows.Storage.Streams;
   
   public class Program
   {
      private const string SerialPortId = "COM6";

      public static void Main()
      {
         SerialDevice serialDevice;

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

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

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

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

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

            DataWriter outputDataWriter = new DataWriter(serialDevice.OutputStream);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

I then tried the device:restart AT command

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

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

The device settings appear not to have returned to factory.

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

nanoFramework RAK811 LoRaWAN library Part2

Shield Serial

My initial RAK811 LPWAN Evaluation Board(EVB) test rig was based on an STM32F7691DISCOVERY. I connected the EVB with jumper leads and sent the AT Command to request the LoRaWAN module version information

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

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

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

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

nanoFramework RAK811 LoRaWAN library Part1

Invalidating the warranty

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

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

RAK 811 EVB schematic pg1
RAK 811 EVB schematic pg2

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

STM32F691Discovery with jumper loopback
STM32F691Discovery with jumper loopback
//---------------------------------------------------------------------------------
// Copyright (c) June 2020, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
//#define ESP32_WROOM   //nanoff --target ESP32_WROOM_32 --serialport COM4 --update
//#define NETDUINO3_WIFI   // nanoff --target NETDUINO3_WIFI --update
//#define MBN_QUAIL // nanoff --target MBN_QUAIL --update
//#define ST_NUCLEO64_F091RC // nanoff --target ST_NUCLEO64_F091RC --update
//#define ST_NUCLEO144_F746ZG //nanoff --target ST_NUCLEO144_F746ZG --update
#define ST_STM32F769I_DISCOVERY      // nanoff --target ST_STM32F769I_DISCOVERY --update 
namespace devMobile.IoT.Rak811.ShieldSerial
{
   using System;
   using System.Diagnostics;
   using System.Threading;
   using Windows.Devices.SerialCommunication;
   using Windows.Storage.Streams;

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

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

      public static void Main()
      {
         SerialDevice serialDevice;

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

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

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

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

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

            DataWriter outputDataWriter = new DataWriter(serialDevice.OutputStream);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Version number check with RAK Serial Port tool

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

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

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