nanoFramework nRF24L01 library Part2

After sorting out Serial Peripheral Interface(SPI) connectivity the next step porting my GHI Electronics TinyCLR V2 library to the nanoFramework was rewriting the initialisation code. Overall changes were minimal as the nanoFramework similar methods to the TinyCLR V2 ones.

The Tiny CLR SPI and interrupt port configuration (note the slightly different interrupt port configuration)

if (gpio == null)
{
   Debug.WriteLine("GPIO Initialization failed.");
}
else
{
   _cePin = gpio.OpenPin(chipEnablePin);
   _cePin.SetDriveMode(GpioPinDriveMode.Output);
   _cePin.Write(GpioPinValue.Low);

   _irqPin = gpio.OpenPin((byte)interruptPin);
   _irqPin.SetDriveMode(GpioPinDriveMode.InputPullUp);
   _irqPin.Write(GpioPinValue.High);
   _irqPin.ValueChanged += _irqPin_ValueChanged;
}

try
{
   var settings = new SpiConnectionSettings()
   {
      ChipSelectType = SpiChipSelectType.Gpio,
      ChipSelectLine = gpio.OpenPin(chipSelectPin),
      Mode = SpiMode.Mode0,
      ClockFrequency = clockFrequency,
      ChipSelectActiveState = false,
   };

   SpiController controller = SpiController.FromName(spiPortName);
   _spiPort = controller.GetDevice(settings);
}
catch (Exception ex)
{
   Debug.WriteLine("SPI Initialization failed. Exception: " + ex.Message);
   return;
}

The nanoFramework SPI and interrupt port configuration (note the slightly different SPI port configuration)

public void Initialize(string spiPortName, int chipEnablePin, int chipSelectPin, int interruptPin, int clockFrequency = 2000000)
{
   var gpio = GpioController.GetDefault();

   if (gpio == null)
   {
      Debug.WriteLine("GPIO Initialization failed.");
   }
   else
   {
      _cePin = gpio.OpenPin(chipEnablePin);
      _cePin.SetDriveMode(GpioPinDriveMode.Output);
      _cePin.Write(GpioPinValue.Low);

      _irqPin = gpio.OpenPin((byte)interruptPin);
      _irqPin.SetDriveMode(GpioPinDriveMode.InputPullUp);
      _irqPin.ValueChanged += irqPin_ValueChanged;
   }

   try
   {
      var settings = new SpiConnectionSettings(chipSelectPin)
      {
         ClockFrequency = clockFrequency,
         Mode = SpiMode.Mode0,
         SharingMode = SpiSharingMode.Shared,
      };

      _spiPort = SpiDevice.FromId(spiPortName, settings);
   }
   catch (Exception ex)
   {
      Debug.WriteLine("SPI Initialization failed. Exception: " + ex.Message);
   return;
   }

The error handling of the initialise method is broken. If the some of the GPIO or SPI port configuration fails a message is displayed in the Debug output but the caller is not notified.

I’m using a Netduino 3 Wifi as the SPI port configuration means I can use a standard Arduino shield to connect up the NRF24L01 wireless module without any jumpers

Netduino 3 Wifi and embedded coolness shield

I have applied the PowerLevel fix from the TinyCLR and Meadow libraries but worry that there maybe other issues.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Address: Dev01
PowerLevel: 2
IsAutoAcknowledge: True
Channel: 15
DataRate: 2
IsDynamicAcknowledge: False
IsDynamicPayload: True
IsEnabled: False
Frequency: 2415
IsInitialized: True
IsPowered: True
00:00:15-TX 9 byte message hello 255
Data Sent!
00:00:15-TX Succeeded!

Based on my experiences porting the library to three similar platforms and debugging it on two others I’m considering writing my own compile-time platform portable library.

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.

TinyCLR OS V2 RC1 LoRa library Part4

Interrupts Revisited

In my last post I had two approaches for fixing the issue with transmit interrupts. As I was sorting out the configuration for my Fezportal device and SS20100 Dev board(both sockets) with a Cascologix MikroBus LoRa click I had similar issues with both receive and transmit.

SC20100 Dev Rev A with Cascologix Click in socket1
Fezportal with Cascologix click

I noticed the extra RegIrqFlags 0X58, Receive-Message in the debugging output.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Sending 13 bytes message Hello LoRa 1!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 2!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X58
Receive-Message
Received 23 byte message  �LoRaIoT1N3WT 20.5,H 86
Transmit-Done
Sending 13 bytes message Hello LoRa 3!
RegIrqFlags 0X08
Transmit-Done

This was with the modified device write methods so I tried changing the Serial Peripheral Interface(SPI) configuration.

public RegisterManager(string spiPortName,  int chipSelectPin, int clockFrequency = 500000)
{
	GpioPin chipSelectGpio = GpioController.GetDefault().OpenPin(chipSelectPin);

	var settings = new SpiConnectionSettings()
	{
		ChipSelectType = SpiChipSelectType.Gpio,
		ChipSelectLine = chipSelectGpio,
		Mode = SpiMode.Mode0,
		ClockFrequency = clockFrequency,
		ChipSelectActiveState = false,
		ChipSelectHoldTime = new TimeSpan(1),
	};

	SpiController spiController = SpiController.FromName(spiPortName);

	rfm9XLoraModem = spiController.GetDevice(settings);
}

When I added the ChipSelectHoldTime (even the smallest possible one) the code worked as expected.

The thread '' (0x2) has exited with code 0 (0x0).
Sending 13 bytes message Hello LoRa 1!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 2!
RegIrqFlags 0X08
Transmit-Done
RegIrqFlags 0X50
Receive-Message
Received 23 byte message �LoRaIoT1N3WT 20.5,H 87
Sending 13 bytes message Hello LoRa 3!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 4!
RegIrqFlags 0X08
Transmit-Done

At this point I have run out of ideas so I will release the code this fix.

TinyCLR OS V2 RC1 LoRa library Part3

Why are Transmit Interrupts broken?

The receive using interrupts appeared to be working but transmit with interrupts I could only send a couple of messages before confirmations stopped.

I had read about restrictions for interrupts pins e.g. PA1 & PB1 can’t be used at the same time, but PA1 and PB2 can, which got me thinking…

In my dragino shield based setup Arduino D2(PA1) is the interrupt(IRQ) line and Arduino D10(PB1) is chip select (CS) so I changed the pins with jumper wires just incase.

Fezduino connected to Dragino LoRa shield with jumpers

I tried several different configurations of CS and IRQ pins and none worked.

On other embedded .net platforms I have written Serial Peripheral Interface(SPI) based drivers for (e.g. Wilderness Labs Meadow and the nanoFramework) there had been issues with the use of device.Write vs. device. TransferFullDuplex (or its equivalent).

The RegisterWriteByte method in the event handler appeared to be the problem so I tried modifying it.

public void RegisterWriteByte(byte address, byte value)
{
   byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
   Debug.Assert(rfm9XLoraModem != null);

   rfm9XLoraModem.Write(writeBuffer);
}

Became

public void RegisterWriteByte(byte address, byte value)
{
   byte[] writeBuffer = new byte[] { address |= RegisterAddressWriteMask, value };
   byte[] readBuffer = new byte[2];
   Debug.Assert(rfm9XLoraModem != null);

   rfm9XLoraModem.TransferFullDuplex(writeBuffer, readBuffer);
}

In the diagnostic output I could see confirmations arriving

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Sending 13 bytes message Hello LoRa 1!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 2!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 3!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 4!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 5!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 6!
RegIrqFlags 0X08
Transmit-Done

This was clue it might be a timing problem, so I took a closer look at how the SPI port was configured. After some experimentation I found that by adding a small ChipSelectHoldTime the .Write statements worked.

When I went back and checked there had also been some timing “tweaks” required to get my .Net Microframework LoRa library to work reliably.

public Rfm9XDevice(string spiPortName, int chipSelectPin, int resetPin, int interruptPin)
{
   GpioController gpioController = GpioController.GetDefault();

   GpioPin chipSelectGpio = gpioController.OpenPin(chipSelectPin);

   var settings = new SpiConnectionSettings()
   {
      ChipSelectType = SpiChipSelectType.Gpio,
      ChipSelectLine = chipSelectGpio,
      Mode = SpiMode.Mode0,
      ClockFrequency = 500000,
      ChipSelectActiveState = false,
      //ChipSelectHoldTime = new TimeSpan(50),
      //ChipSelectHoldTime = new TimeSpan(25),
      //ChipSelectHoldTime = new TimeSpan(10),
      ChipSelectHoldTime = new TimeSpan(5),
      //ChipSelectHoldTime = new TimeSpan(1),
   };

   SpiController spiController = SpiController.FromName(spiPortName);

   rfm9XLoraModem = spiController.GetDevice(settings);

   // Factory reset pin configuration
   GpioPin resetGpioPin = gpioController.OpenPin(resetPin);
   resetGpioPin.SetDriveMode(GpioPinDriveMode.Output);
   resetGpioPin.Write(GpioPinValue.Low);
   Thread.Sleep(10);
   resetGpioPin.Write(GpioPinValue.High);
   Thread.Sleep(10);

   // Interrupt pin for RX message & TX done notification 
   InterruptGpioPin = gpioController.OpenPin(interruptPin);
   InterruptGpioPin.SetDriveMode(GpioPinDriveMode.Input);

   InterruptGpioPin.ValueChanged += InterruptGpioPin_ValueChanged;
}

In the diagnostic output I could see confirmations arriving

...
Sending 16 bytes message Hello LoRa 1115!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1116!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1117!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1118!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1119!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1120!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1121!
RegIrqFlags 0X08
Transmit-Done
Sending 16 bytes message Hello LoRa 1122!
RegIrqFlags 0X08
The program '[13] TinyCLR application: Managed' has exited with code 0 (0x0).

After some soak testing it looks like the ChipSelectHoldTime modification works pretty reliably but I will need watch for issues.

EDIT: After a long walk I have updated the code to use TransferFullDuplex rather than add a ChipSelectHoldTime.

TinyCLR OS V2 RC1 LoRa library Part2

Receive and Transmit

The first step was to confirm the transmission of messages with polled completion confirmation was working as expected.

   class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13, SC20100.GpioPin.PA14);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1, SC20100.GpioPin.PA15);
#endif
         int SendCount = 0;

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

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

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

         rfm9XDevice.RegisterDump();

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

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

            string messageText = $"Hello LoRa {SendCount += 1}!";
               
            // load the message into the fifo
            byte[] messageBytes = UTF8Encoding.UTF8.GetBytes(messageText);
            rfm9XDevice.RegisterWrite(0x0, messageBytes); // RegFifo

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

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

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

            Thread.Sleep(30000);
         }
      }
   }

The diagnostic output shows messages being sent and on another device I could see the messages arriving. I do wonder why the first message often takes so long to send?

Register dump
Register 0x00 - Value 0Xc3
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 0X80
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 0X00
Register 0x21 - Value 0X08
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
Sending 13 bytes message Hello LoRa 1!
Send-wait
.
.
.
.
.
Send-Done
Sending 13 bytes message Hello LoRa 2!
Send-wait
Send-Done
Sending 13 bytes message Hello LoRa 3!
Send-wait
Send-Done
Sending 13 bytes message Hello LoRa 4!
Send-wait
Send-Done
Sending 13 bytes message Hello LoRa 5!
Send-wait
Send-Done
Sending 13 bytes message Hello LoRa 6!
Send-wait
Send-Done

The second step was to confirm the polled reception of messages was working as expected.

   class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13, SC20100.GpioPin.PA14);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1, SC20100.GpioPin.PA15);
#endif


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

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

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

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

         while (true)
         {
            // Wait until a packet is received, no timeouts in PoC
            Debug.WriteLine("Receive-Wait");
            byte irqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
            while ((irqFlags & 0b01000000) == 0)  // wait until RxDone cleared
            {
               Thread.Sleep(100);
               irqFlags = rfm9XDevice.RegisterReadByte(0x12); // RegIrqFlags
               //Debug.Write(".");
            }
            Debug.WriteLine("");
            Debug.WriteLine($"RegIrqFlags 0X{irqFlags:X2}");
            Debug.WriteLine("Receive-Message");
            byte currentFifoAddress = rfm9XDevice.RegisterReadByte(0x10); // RegFifiRxCurrent
            rfm9XDevice.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr

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

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

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

            string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
            Debug.WriteLine($"Received {messageBytes.Length} byte message {messageText}");

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

The diagnostic output shows messages being received from one of my other devices.

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

RegIrqFlags 0X50
Receive-Message
Received 23 byte message �LoRaIoT1N3WT 18.8,H 78
Receive-Done
Receive-Wait

RegIrqFlags 0X50
Receive-Message
Received 23 byte message �LoRaIoT1N3WT 18.8,H 78
Receive-Done
Receive-Wait

The next step was to confirm the interrupt driven reception of messages was working as expected.

   class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13, SC20100.GpioPin.PA14, SC20100.GpioPin.PE4);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1, SC20100.GpioPin.PA15, SC20100.GpioPin.PA1);
#endif

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

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

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

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

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

         rfm9XDevice.RegisterDump();

         Debug.WriteLine("Receive-Wait");
         Thread.Sleep(Timeout.Infinite);
      }
   }

      private void InterruptGpioPin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs e)
      {
         if (e.Edge != GpioPinEdge.RisingEdge)
         {
            return;
         }

         byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
         Debug.WriteLine($"RegIrqFlags 0X{irqFlags:x2}");
         if ((irqFlags & 0b01000000) == 0b01000000)  // RxDone 
         {
            Debug.WriteLine("Receive-Message");
            byte currentFifoAddress = this.RegisterReadByte(0x10); // RegFifiRxCurrent
            this.RegisterWriteByte(0x0d, currentFifoAddress); // RegFifoAddrPtr

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

            // Get number of bytes in the message
            byte[] messageBytes = this.RegisterRead(0x00, numberOfBytes);

            string messageText = UTF8Encoding.UTF8.GetString(messageBytes);
            Debug.WriteLine($"Received {messageBytes.Length} byte message {messageText}");
         }

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

The diagnostic output shows messages being received from one of my other devices.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Receive-Wait
RegIrqFlags 0X50
Receive-Message
Received 23 byte message  �LoRaIoT1N3WT 18.8,H 78
RegIrqFlags 0X50
Receive-Message
Received 23 byte message  �LoRaIoT1N3WT 18.7,H 79

The final step was to confirm the interrupt driven transmission of messages was working as expected.

   class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13, SC20100.GpioPin.PA14, SC20100.GpioPin.PE4);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1, SC20100.GpioPin.PA15, SC20100.GpioPin.PA1); // Doesn't work
#endif
         int SendCount = 0;

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

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

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

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

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

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

            string messageText = $"Hello LoRa {SendCount += 1}!";

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

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

            Thread.Sleep(10000);
         }
      }
   }


private void InterruptGpioPin_ValueChanged(GpioPin sender, GpioPinValueChangedEventArgs e)
      {
         if (e.Edge != GpioPinEdge.RisingEdge)
         {
            return;
         }

         byte irqFlags = this.RegisterReadByte(0x12); // RegIrqFlags
         Debug.WriteLine($"RegIrqFlags 0X{irqFlags:x2}");

         if ((irqFlags & 0b00001000) == 0b00001000)  // TxDone
         {
            Debug.WriteLine("Transmit-Done");
         }

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

The diagnostic output shows messages being sent but after the first message (sometimes the second or third) there are no confirmations.

The thread ” (0x2) has exited with code 0 (0x0).
Sending 13 bytes message Hello LoRa 1!
RegIrqFlags 0X08
Transmit-Done
Sending 13 bytes message Hello LoRa 2!
Sending 13 bytes message Hello LoRa 3!
Sending 13 bytes message Hello LoRa 4!
Sending 13 bytes message Hello LoRa 5!
Sending 13 bytes message Hello LoRa 6!
Sending 13 bytes message Hello LoRa 7!
Sending 13 bytes message Hello LoRa 8!
Sending 13 bytes message Hello LoRa 9!
Sending 14 bytes message Hello LoRa 10!
Sending 14 bytes message Hello LoRa 11!
Sending 14 bytes message Hello LoRa 12!
Sending 14 bytes message Hello LoRa 13!
Sending 14 bytes message Hello LoRa 14!

It looks like something has been broken (possibly by RC1) in my implementation of interrupt driven transmission of messages.

TinyCLR OS V2 RC1 LoRa library Part1

The Basics

A week ago a selection of Single Board Computers(SBC) arrived from GHI Electronics. Previously I had been working with a SC20100 Dev board which has mikroBUS Click sockets which limited my peripheral options. There were several different device form factors in the package so I started with a Fezduino and Dragino LoRa shield for Arduino.

Fezduino with Dragino Shield

Need to be careful not to push the Dragino shield in too far as a couple of the pins (one is not connected and the other is IOREF) will contact the Micro SD card slot. (I have put a strip of Duct tape on the top of the Micro SD card socket)

Fezduino pin clearance

The first step was to get basic connectivity sorted. I opened the RFM9XLoRa-TinyCLR repository and modified the Serial Peripheral Interface(SPI) and chip select(CS) settings of the ShieldSPI project, then updated the NuGet packages (public feed rather than my local preview files).

Dragino LoRa Shield for Arduino pins

I have left the TinyCLR V1 configuration in for backward compatibility

#if TINYCLR_V1_FEZDUINO
            ChipSelectLine = FEZ.GpioPin.D10,
#endif
#if TINYCLR_V2_SC20100DEV
            ChipSelectLine = GHIElectronics.TinyCLR.Devices.Gpio.GpioController.GetDefault().OpenPin(SC20100.GpioPin.PA13),
#endif
#if TINYCLR_V2_FEZDUINO
            ChipSelectLine = GHIElectronics.TinyCLR.Devices.Gpio.GpioController.GetDefault().OpenPin(GHIElectronics.TinyCLR.Pins.SC20100.GpioPin.PB1),
#endif

When I ran the application in Visual Studio I could reliably read the RegVersion register.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Value = 0x00-12
Value = 0x00-12
Value = 0x00-12
Value = 0x00-12
Value = 0x00-12
Value = 0x00-12
The program '[5] TinyCLR application: Managed' has exited with code 0 (0x0).

The next step was to modify the RegisterScan project to check I could read all the SX127X configuration registers.

  class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1);
#endif

         while (true)
         {
            for (byte registerIndex = 0; registerIndex <= 0x42; registerIndex++)
            {
               byte registerValue = rfm9XDevice.RegisterReadByte(registerIndex);

               Debug.WriteLine($"Register 0x{registerIndex:x2} - Value 0X{registerValue:x2}");
            }
            Debug.WriteLine("");

            Thread.Sleep(10000);
         }
      }
   }

When I ran the application in Visual Studio I could reliably read the registers 0x00 through 0x42.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
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 0X71
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 0Xfb
Register 0x3d - Value 0X02
Register 0x3e - Value 0X80
Register 0x3f - Value 0X40
Register 0x40 - Value 0X00
Register 0x41 - Value 0X00
Register 0x42 - Value 0X12

The next step was to modify the RegisterReadAndWrite project to check I could read and write the SX127X configuration registers.

     class Program
   {
      static void Main()
      {
#if TINYCLR_V2_SC20100DEV
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi3, SC20100.GpioPin.PA13, SC20100.GpioPin.PA14);
#endif
#if TINYCLR_V2_FEZDUINO
         Rfm9XDevice rfm9XDevice = new Rfm9XDevice(SC20100.SpiBus.Spi6, SC20100.GpioPin.PB1, SC20100.GpioPin.PA15);
#endif

         rfm9XDevice.RegisterDump();

         while (true)
         {
            Debug.WriteLine("Read RegOpMode (read byte)");
            Byte regOpMode1 = rfm9XDevice.RegisterReadByte(0x1);
            Debug.WriteLine($"RegOpMode 0x{regOpMode1:x2}");

            Debug.WriteLine("Set LoRa mode and sleep mode (write byte)");
            rfm9XDevice.RegisterWriteByte(0x01, 0b10000000);

            Debug.WriteLine("Read RegOpMode (read byte)");
            Byte regOpMode2 = rfm9XDevice.RegisterReadByte(0x1);
            Debug.WriteLine($"RegOpMode 0x{regOpMode2:x2}");

            Debug.WriteLine("Read the preamble (read word)");
            ushort preamble = rfm9XDevice.RegisterReadWord(0x20);
            Debug.WriteLine($"Preamble 0x{preamble:x2}");

            Debug.WriteLine("Set the preamble to 0x80 (write word)");
            rfm9XDevice.RegisterWriteWord(0x20, 0x80);

            Debug.WriteLine("Read the center frequency (read byte array)");
            byte[] frequencyReadBytes = rfm9XDevice.RegisterRead(0x06, 3);
            Debug.WriteLine($"Frequency Msb 0x{frequencyReadBytes[0]:x2} Mid 0x{frequencyReadBytes[1]:x2} Lsb 0x{frequencyReadBytes[2]:x2}");

            Debug.WriteLine("Set the center frequency to 915MHz (write byte array)");
            byte[] frequencyWriteBytes = { 0xE4, 0xC0, 0x00 };
            rfm9XDevice.RegisterWrite(0x06, frequencyWriteBytes);

            rfm9XDevice.RegisterDump();

            Thread.Sleep(30000);
         }
      }

When I ran the application in Visual Studio I could read and write register values.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Register dump
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 0X71
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 0Xfa
Register 0x3d - Value 0X02
Register 0x3e - Value 0X80
Register 0x3f - Value 0X40
Register 0x40 - Value 0X00
Register 0x41 - Value 0X00
Register 0x42 - Value 0X12
Read RegOpMode (read byte)
RegOpMode 0x09
Set LoRa mode and sleep mode (write byte)
Read RegOpMode (read byte)
RegOpMode 0x80
Read the preamble (read word)
Preamble 0x08
Set the preamble to 0x80 (write word)
Read the center frequency (read byte array)
Frequency Msb 0x6c Mid 0x80 Lsb 0x00
Set the center frequency to 915MHz (write byte array)
Register dump
Register 0x00 - Value 0Xc3
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

At this point I was confident that I could hardware reset the shield and read/modify registers on the SX127X.

RAK811 LPWAN EVB Part3

Invalidating the warranty…

I wanted the RAK811 LPWAN Evaluation Board(EVB) -AS923 to work with selection of my Arduino and nanoFramework devices. The first decision was which of the hardware serial port (D0,D1) or the software serial port (D10,D11) should be connected to P1?

To use the EVB with my STM32F691DISCOVERY board running the nanoFramework (COM5 on the hardware serial port pins D0,D1) I removed R17&R19.

After some tinkering, I found that R8 which is connected to the RAK811 module reset had to be cut as well for the shield to work on my Arduino Uno R3 and STM32F691DISCOVERY devices.

RAK811 EVB with R17,R19 & R8 cut

I can still run the Arduino Uno R3 and RAK811 EVB in the original configuration with a couple of jumper leads

RAK811 on Arduino with Serial connected to D10,D1 a SoftwareSerial port

For devices where I needed D10,D11 for a  Serial Peripheral Interface(SPI) I could use an FTDI board and a couple of other pins (in this case D2,D3) for serial logging.

RAK811 on Arduino with Serial connected to D2,D2 a SoftwareSerial port

After debugging some code I also replaced the small jumpers on P1 with a couple of jumper leads so it was less fiddly to swap from downloading to debugging.

RAK811 LPWAN EVB Part2

How can I use this…

Just over a week ago I purchased a RAK811 LPWAN Evaluation Board -AS923 and now I want to trial it with selection of devices and configurations.

Initially I didn’t want to modify the shield by removing resistors as I only have one, and I’m not certain what device(s) it will be used with. The initial hardware configuration required jumpers for the serial port, ground and 5V power.

Arduino Uno R3 and RAK811 LPWAN Evaluation board 5V config

After looking at the schematic it should be possible to use the shield with a 3v3 device.

RAK 811 EVB schematic pg1
RAK 811 EVB schematic pg2

I confirmed this with a Seeeduino V4.2 devices set to 3v3, by putting a jumper on J1 and shifting the jumper wire from the 5V to the 3V3 pin.

Seeeduino V4 and RAK811 LPWAN Evaluation board 3V3 config

The next step was to see how I could get the RAK shield working on other devices without jumpers. On Arduino Uno R3 devices D0&D1 are the hardware(HW) serial port which are used for uploading sketches, and diagnostic logging.

The shield also connects the module serial port to D0&D1 to D10&D11, so by removing R17&R19 the shield should work on a device This would also allow the use of the Serial Peripheral Interface(SPI) port for other applications.

Using the HW Serial port but without any logging.

Unplugging the jumpers to upload was painful but the lack of logging made it really hard to debug my code.

To get around this I configured a SoftwareSerial port on D2&D3 for logging.

/********************************************************
 * This demo is only supported after RUI firmware version 3.0.0.13.X on RAK811
 * Master Board Uart Receive buffer size at least 128 bytes. 
 ********************************************************/
//#define SERIAL_BUFFER_SIZE 128
//#define SERIAL_TX_BUFFER_SIZE 64
//#define SERIAL_RX_BUFFER_SIZE 128
//#define _SS_MAX_RX_BUFF 128
#include "RAK811.h"
#include "SoftwareSerial.h"
#define WORK_MODE LoRaWAN   //  LoRaWAN or LoRaP2P
#define JOIN_MODE OTAA    //  OTAA or ABP
#if JOIN_MODE == OTAA
String DevEui = "..."; // From TTN
String AppEui = "...";
String AppKey = "...";
#else JOIN_MODE == ABP
String NwkSKey = "...";
String AppSKey = "...";
String DevAddr = "...";
#endif

#define TXpin 3   // Set the virtual serial port pins
#define RXpin 2

SoftwareSerial DebugSerial(RXpin,TXpin); // Declare a virtual serial port for debugging
#define ATSerial Serial

char buffer[]= "48656C6C6F20776F726C6435";

bool InitLoRaWAN(void);
RAK811 RAKLoRa(ATSerial,DebugSerial);

void setup() {
  DebugSerial.begin(19200);
  DebugSerial.println(F("Starting"));
  while(DebugSerial.available())
  {
    DebugSerial.read(); 
  }
  
  ATSerial.begin(9600); //set ATSerial baudrate:This baud rate has to be consistent with  the baud rate of the WisNode device.
  while(ATSerial.available())
  {
    ATSerial.read(); 
  }

  if(!RAKLoRa.rk_setWorkingMode(0))  //set WisNode work_mode to LoRaWAN.
  {
    DebugSerial.println(F("set work_mode failed, please reset module."));
    while(1);
  }
  
  RAKLoRa.rk_getVersion();  //get RAK811 firmware version
  DebugSerial.println(RAKLoRa.rk_recvData());  //print version number

  DebugSerial.println(F("Start init RAK811 parameters..."));
 
  if (!InitLoRaWAN())  //init LoRaWAN
  {
    DebugSerial.println(F("Init error,please reset module.")); 
    while(1);
  }

  DebugSerial.println(F("Start to join LoRaWAN..."));
  while(!RAKLoRa.rk_joinLoRaNetwork(60))  //Joining LoRaNetwork timeout 60s
  {
    DebugSerial.println();
    DebugSerial.println(F("Rejoin again after 5s..."));
    delay(5000);
  }
  DebugSerial.println(F("Join LoRaWAN success"));

  if(!RAKLoRa.rk_isConfirm(0))  //set LoRa data send package type:0->unconfirm, 1->confirm
  {
    DebugSerial.println(F("LoRa data send package set error,please reset module.")); 
    while(1);    
  }
}

bool InitLoRaWAN(void)
{
  if(RAKLoRa.rk_setJoinMode(JOIN_MODE))  //set join_mode:OTAA
  {
    if(RAKLoRa.rk_setRegion(0))  //set region EU868
    {
      if (RAKLoRa.rk_initOTAA(DevEui, AppEui, AppKey))
      {
        DebugSerial.println(F("RAK811 init OK!"));  
        return true;    
      }
    }
  }
  return false;
}

void loop() 
{
  DebugSerial.println(F("Start send data..."));
  if (RAKLoRa.rk_sendData(1, buffer))
  {    
    //for (unsigned long start = millis(); millis() - start < 300000L;)
    for (unsigned long start = millis(); millis() - start < 10000L;)
    {
      String ret = RAKLoRa.rk_recvData();
      if(ret != NULL)
      { 
        DebugSerial.println("ret != NULL");
        DebugSerial.println(ret);
      }
      if((ret.indexOf("OK")>0)||(ret.indexOf("ERROR")>0))
      {
        DebugSerial.println(F("Go to Sleep."));
        RAKLoRa.rk_sleep(1);  //Set RAK811 enter sleep mode
        delay(10000);  //delay 10s
        RAKLoRa.rk_sleep(0);  //Wakeup RAK811 from sleep mode
        break;
      }
    }
  }
}

I used an FTDI module I had lying around to connect the diagnostic logging serial port on the test rig to my development box.

Using the HW Serial port but with logging.

Now I only had to unplug the jumpers for D0&D1 and change ports in the Arduino IDE. One port for debugging the other for downloading.

Depending on the application I may remove R8 so I can manually reset the shield.

TinyCLR OS V2 nRF24L01 library Part2

After sorting out Serial Peripheral Interface(SPI) connectivity the next step porting the techfooninja nRF24L01P library to GHI Electronics TinyCLR was rewriting the initialisation code. Overall changes were minimal as the TinyCLR V2 SPI library has similar methods to the Windows 10 IoT Core ones.

SC20100 and MikroE nRF24 C Click

I need to refactor the initialise method so that failure exceptions are not caught and add the interrupt trigger edge so I can remove test from the handler.

      public void Initialize(string spiPortName, byte chipEnablePin, byte chipSelectPin, byte interruptPin, int clockFrequency = 2000000)
      {
         var gpio = GpioController.GetDefault();

         if (gpio == null)
         {
            Debug.WriteLine("GPIO Initialization failed.");
         }
         else
         {
            _cePin = gpio.OpenPin(chipEnablePin);
            _cePin.SetDriveMode(GpioPinDriveMode.Output);
            _cePin.Write(GpioPinValue.Low);

            _irqPin = gpio.OpenPin((byte)interruptPin);
            _irqPin.SetDriveMode(GpioPinDriveMode.InputPullUp);
            _irqPin.Write(GpioPinValue.High);
            _irqPin.ValueChanged += _irqPin_ValueChanged;
         }

         try
         {
            var settings = new SpiConnectionSettings()
            {
               ChipSelectType = SpiChipSelectType.Gpio,
               ChipSelectLine = gpio.OpenPin(chipSelectPin),
               Mode = SpiMode.Mode0,
               ClockFrequency = clockFrequency,
               ChipSelectActiveState = false,
            };

            SpiController controller = SpiController.FromName(spiPortName);
            _spiPort = controller.GetDevice(settings);
         }
         catch (Exception ex)
         {
            Debug.WriteLine("SPI Initialization failed. Exception: " + ex.Message);
            return;
         }

         // Module reset time
         Thread.Sleep(100);

         IsInitialized = true;

         // Set reasonable default values
         Address = Encoding.UTF8.GetBytes("NRF1");
         DataRate = DataRate.DR2Mbps;
         IsDynamicPayload = true;
         IsAutoAcknowledge = true;

         FlushReceiveBuffer();
         FlushTransferBuffer();
         ClearIrqMasks();
         SetRetries(5, 60);

         // Setup, CRC enabled, Power Up, PRX
         SetReceiveMode();
      }

The Initialise method gained parameters for the SPI port name and SPI clock frequency.

      static void Main()
      {
         RF24 Radio = new RF24();

         try
         {
            Radio.OnDataReceived += Radio_OnDataReceived;
            Radio.OnTransmitFailed += Radio_OnTransmitFailed;
            Radio.OnTransmitSuccess += Radio_OnTransmitSuccess;

            // SC20100.GpioPin.PD3
            Radio.Initialize(SC20100.SpiBus.Spi3, SC20100.GpioPin.PD4, SC20100.GpioPin.PD3, SC20100.GpioPin.PC5);
            Radio.Address = Encoding.UTF8.GetBytes(DeviceAddress);

            Radio.Channel = 15;
            //Radio.PowerLevel = PowerLevel.Max;
            //Radio.PowerLevel = PowerLevel.High;
            //Radio.PowerLevel = PowerLevel.Low;
            //Radio.PowerLevel = PowerLevel.Minimum
            Radio.DataRate = DataRate.DR250Kbps;
            //Radio.DataRate = DataRate.DR1Mbps;
            Radio.IsEnabled = true;

            Radio.IsAutoAcknowledge = true;
            Radio.IsDyanmicAcknowledge = false;
            Radio.IsDynamicPayload = true;

            Debug.WriteLine($"Address: {Encoding.UTF8.GetString(Radio.Address)}");
            Debug.WriteLine($"PowerLevel: {Radio.PowerLevel}");
            Debug.WriteLine($"IsAutoAcknowledge: {Radio.IsAutoAcknowledge}");
            Debug.WriteLine($"Channel: {Radio.Channel}");
            Debug.WriteLine($"DataRate: {Radio.DataRate}");
            Debug.WriteLine($"IsDynamicAcknowledge: {Radio.IsDyanmicAcknowledge}");
            Debug.WriteLine($"IsDynamicPayload: {Radio.IsDynamicPayload}");
            Debug.WriteLine($"IsEnabled: {Radio.IsEnabled}");
            Debug.WriteLine($"Frequency: {Radio.Frequency}");
            Debug.WriteLine($"IsInitialized: {Radio.IsInitialized}");
            Debug.WriteLine($"IsPowered: {Radio.IsPowered}");

            while (true)
            {
               string payload = "hello " + DateTime.Now.Second;
               Debug.WriteLine($"{DateTime.UtcNow:HH:mm:ss}-TX {payload.Length} byte message {payload}");
               Radio.SendTo(Encoding.UTF8.GetBytes(BaseStationAddress), Encoding.UTF8.GetBytes(payload));

               Thread.Sleep(30000);
            }
         }
         catch (Exception ex)
         {
            Debug.WriteLine(ex.Message);

            return;
         }
      }

I can send and receive messages but the PowerLevel doesn’t look right so I need to apply fix from the Meadow version.

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Address: Dev01
PowerLevel: 15
IsAutoAcknowledge: True
Channel: 15
DataRate: 2
IsDynamicAcknowledge: False
IsDynamicPayload: True
IsEnabled: False
Frequency: 2415
IsInitialized: True
IsPowered: True
00:00:01-TX 7 byte message hello 1
Data Sent!
00:00:01-TX Succeeded!
00:00:31-TX 8 byte message hello 31
Data Sent!
00:00:31-TX Succeeded!

TinyCLR OS V2 nRF24L01 library Part1

After debugging Windows 10 IoT Core, .NetMF and Wilderness Labs Meadow nRF24L01P libraries I figured yet another port, this time to a GHI Electronics Tiny CLR V2 powered device shouldn’t be “rocket science”.

This test rig uses SC20100S Dev and MikroE nRF C Click boards.

//---------------------------------------------------------------------------------
// Copyright (c) May 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.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.nRf24L01.ModuleSPI
{
   using System;
   using System.Diagnostics;
   using System.Reflection;
   using System.Text;
   using System.Threading;

   using GHIElectronics.TinyCLR.Devices.Gpio;
   using GHIElectronics.TinyCLR.Devices.Spi;
   using GHIElectronics.TinyCLR.Pins;

   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";
      static SpiDevice nrf24L01Device;

      static void Main()
      {
         try
         {
            GpioController gpioController = GpioController.GetDefault();

            var settings = new SpiConnectionSettings()
            {
               ChipSelectType = SpiChipSelectType.Gpio,
               //ChipSelectLine = FEZ.GpioPin.D10,
               ChipSelectLine = gpioController.OpenPin(SC20100.GpioPin.PD3),
               Mode = SpiMode.Mode0,
               //Mode = SpiMode.Mode1,
               //Mode = SpiMode.Mode2,
               //Mode = SpiMode.Mode3,
               ClockFrequency = 500000,
               //ChipSelectActiveState = true
               ChipSelectActiveState = false,
               //ChipSelectHoldTime = new TimeSpan(0, 0, 0, 0, 500),
               //ChipSelectSetupTime = new TimeSpan(0, 0, 0, 0, 500),
            };

            var spiController = SpiController.FromName(SC20100.SpiBus.Spi3);

            Debug.WriteLine("nrf24L01Device Device...");
            nrf24L01Device = spiController.GetDevice(settings);
            if (nrf24L01Device == null)
            {
               Debug.WriteLine("nrf24L01Device == null");
            }

            Thread.Sleep(100);

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

            Thread.Sleep(500);
         }
         catch (Exception ex)
         {
            Debug.WriteLine("Configure SpiPort " + ex.Message);
         }

         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));
            nrf24L01Device.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];
            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));
            nrf24L01Device.Write(txBuffer2);
            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));
            nrf24L01Device.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));
            nrf24L01Device.TransferFullDuplex(txBuffer4, rxBuffer4);
            Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer4));

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

            // Write the RF Channel
            Debug.WriteLine("RF Channel write");
            byte[] txBuffer5 = new byte[] { RF_CH | W_REGISTER, rxBuffer4[1]+=1};

            Debug.WriteLine(" nrf24L01Device.Write...RF_CH");
            Debug.WriteLine(" txBuffer:" + BitConverter.ToString(txBuffer5));
            nrf24L01Device.Write(txBuffer5);
            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));
            nrf24L01Device.TransferFullDuplex(txBuffer6, rxBuffer6);
            Debug.WriteLine(" rxBuffer:" + BitConverter.ToString(rxBuffer6));

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

After lots of tinkering with SPI configuration options I can read and write my nRF24L01 device receive port address

The thread '<No Name>' (0x2) has exited with code 0 (0x0).
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-15
RF Channel 1 0x05 - Value 0X15 - Value adjusted 2421

RF Channel write
 nrf24L01Device.Write...RF_CH
 txBuffer:25-16

RF Channel read 2
 nrf24L01Device.TransferFullDuplex...RF_CH
 txBuffer:05-00
 rxBuffer:0E-16
RF Channel 2 0x05 - Value 0X16 - Value adjusted 2422