Over the years I have ported my HopeRF RFM9X(Now a generic Semtech SX127X ) Windows 10 IoT Core (May 2018) library to .NET microFramework(May 2018), Wilderness Labs Meadow(Jan 2020), GHI Electronics TinyCLR-OS(July 2020), .NET nanoFramework V1(May 2020) and .NET Core(Aug 2021).
All this madness started because I wasn’t confident the frequency calculation of the Emmellsoft Dragino.Lora code was correct. Over the last couple of years I have also found bugs in my Transmit Power, InvertIQ RX/TX with many others yet to be discovered.
For my updated .NET nanoFramework port I have mainly used a half a dozen Dragino LoRa shields for Arduino and Netduino 3 Wifi devices I had lying around. I have also tested the code with SparkFun LoRa Gateway-1-Channel (ESP32) and ST 32F769IDiscovery devices.
The Dragino shield uses D10 for chip select, D2 for RFM9X DI0 interrupt and D9 for Reset.
Netduino 3 Wifi pin mapping
- D10->CS->PB10
- D9->RST->E5
ST 32F769IDiscovery pin mapping
D10->CS->PA11
D9->RST->PH6
SparkFun LoRa Gateway-1-Channel (ESP32) pin mapping(SX127X reset is not connected)
- CS->PB10
The first step was to confirm I could read a single(ShieldSPI) then scan all the Semtech SX1276 registers with the new nanoFramework System.Device.SPI Nuget (which was”inspired by” .Net Core System.Device.SPI)
namespace devMobile.IoT.SX127x.ShieldSPI
{
using System;
using System.Diagnostics;
using System.Threading;
using System.Device.Gpio;
using System.Device.Spi;
#if ESP32_WROOM_32_LORA_1_CHANNEL
using nanoFramework.Hardware.Esp32;
#endif
public class Program
{
private const byte RegVersion = 0x42;
#if ESP32_WROOM_32_LORA_1_CHANNEL
private const int SpiBusId = 1;
#endif
#if NETDUINO3_WIFI
private const int SpiBusId = 2;
#endif
#if ST_STM32F769I_DISCOVERY
private const int SpiBusId = 2;
#endif
public static void Main()
{
GpioController gpioController = new GpioController();
#if ESP32_WROOM_32_LORA_1_CHANNEL // No reset line for this device as it isn't connected on SX127X
int ledPinNumber = Gpio.IO17;
int chipSelectLine = Gpio.IO16;
#endif
#if NETDUINO3_WIFI
int ledPinNumber = PinNumber('A', 10);
// Arduino D10->PB10
int chipSelectLine = PinNumber('B', 10);
// Arduino D9->PE5
int resetPinNumber = PinNumber('E', 5);
#endif
#if ST_STM32F769I_DISCOVERY
int ledPinNumber = PinNumber('J', 5);
// Arduino D10->PA11
int chipSelectLine = PinNumber('A', 11);
// Arduino D9->PH6
int resetPinNumber = PinNumber('H', 6);
#endif
Debug.WriteLine("devMobile.IoT.SX127x.ShieldSPI starting");
try
{
#if ESP32_WROOM_32_LORA_1_CHANNEL || NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
// Setup the onboard LED
gpioController.OpenPin(ledPinNumber, PinMode.Output);
#endif
#if NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
// Setup the reset pin
gpioController.OpenPin(resetPinNumber, PinMode.Output);
gpioController.Write(resetPinNumber, PinValue.High);
#endif
#if ESP32_WROOM_32_LORA_1_CHANNEL
Configuration.SetPinFunction(Gpio.IO12, DeviceFunction.SPI1_MISO);
Configuration.SetPinFunction(Gpio.IO13, DeviceFunction.SPI1_MOSI);
Configuration.SetPinFunction(Gpio.IO14, DeviceFunction.SPI1_CLOCK);
#endif
var settings = new SpiConnectionSettings(SpiBusId, chipSelectLine)
{
ClockFrequency = 1000000,
Mode = SpiMode.Mode0,// From SemTech docs pg 80 CPOL=0, CPHA=0
SharingMode = SpiSharingMode.Shared,
};
using (SpiDevice device = SpiDevice.Create(settings))
{
Thread.Sleep(500);
while (true)
{
byte[] writeBuffer = new byte[] { RegVersion, 0x0 };
byte[] readBuffer = new byte[writeBuffer.Length];
device.TransferFullDuplex(writeBuffer, readBuffer);
Debug.WriteLine(String.Format("Register 0x{0:x2} - Value 0X{1:x2}", RegVersion, readBuffer[1]));
#if ESP32_WROOM_32_LORA_1_CHANNEL || NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
if ( gpioController.Read(ledPinNumber) == PinValue.High)
{
gpioController.Write(ledPinNumber, PinValue.Low);
}
else
{
gpioController.Write(ledPinNumber, PinValue.High);
}
#endif
Thread.Sleep(10000);
}
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
}
#if NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
static int PinNumber(char port, byte pin)
{
if (port < 'A' || port > 'J')
throw new ArgumentException();
return ((port - 'A') * 16) + pin;
}
#endif
}
}
namespace devMobile.IoT.SX127x.RegisterScan
{
using System;
using System.Diagnostics;
using System.Threading;
using System.Device.Gpio;
using System.Device.Spi;
#if ESP32_WROOM_32_LORA_1_CHANNEL
using nanoFramework.Hardware.Esp32;
#endif
public sealed class SX127XDevice
{
private readonly SpiDevice SX127XTransceiver;
public SX127XDevice(int busId, int chipSelectLine)
{
var settings = new SpiConnectionSettings(busId, chipSelectLine)
{
ClockFrequency = 1000000,
Mode = SpiMode.Mode0,// From SemTech docs pg 80 CPOL=0, CPHA=0
SharingMode = SpiSharingMode.Shared
};
SX127XTransceiver = new SpiDevice(settings);
}
public SX127XDevice(int busId, int chipSelectLine, int resetPin)
{
var settings = new SpiConnectionSettings(busId, chipSelectLine)
{
ClockFrequency = 1000000,
Mode = SpiMode.Mode0,// From SemTech docs pg 80 CPOL=0, CPHA=0
SharingMode = SpiSharingMode.Shared
};
SX127XTransceiver = new SpiDevice(settings);
// Factory reset pin configuration
GpioController gpioController = new GpioController();
gpioController.OpenPin(resetPin, PinMode.Output);
gpioController.Write(resetPin, PinValue.Low);
Thread.Sleep(20);
gpioController.Write(resetPin, PinValue.High);
Thread.Sleep(20);
}
public Byte RegisterReadByte(byte registerAddress)
{
byte[] writeBuffer = new byte[] { registerAddress, 0x0 };
byte[] readBuffer = new byte[writeBuffer.Length];
SX127XTransceiver.TransferFullDuplex(writeBuffer, readBuffer);
return readBuffer[1];
}
}
public class Program
{
#if ESP32_WROOM_32_LORA_1_CHANNEL
private const int SpiBusId = 1;
#endif
#if NETDUINO3_WIFI
private const int SpiBusId = 2;
#endif
#if ST_STM32F769I_DISCOVERY
private const int SpiBusId = 2;
#endif
public static void Main()
{
#if ESP32_WROOM_32_LORA_1_CHANNEL
int chipSelectLine = Gpio.IO16;
#endif
#if NETDUINO3_WIFI
// Arduino D10->PB10
int chipSelectLine = PinNumber('B', 10);
// Arduino D9->PE5
int resetPinNumber = PinNumber('E', 5);
#endif
#if ST_STM32F769I_DISCOVERY
// Arduino D10->PA11
int chipSelectLine = PinNumber('A', 11);
// Arduino D9->PH6
int resetPinNumber = PinNumber('H', 6);
#endif
Debug.WriteLine("devMobile.IoT.SX127x.RegisterScan starting");
try
{
#if NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
SX127XDevice sx127XDevice = new SX127XDevice(SpiBusId, chipSelectLine, resetPinNumber);
#endif
#if ESP32_WROOM_32_LORA_1_CHANNEL
Configuration.SetPinFunction(Gpio.IO12, DeviceFunction.SPI1_MISO);
Configuration.SetPinFunction(Gpio.IO13, DeviceFunction.SPI1_MOSI);
Configuration.SetPinFunction(Gpio.IO14, DeviceFunction.SPI1_CLOCK);
SX127XDevice sx127XDevice = new SX127XDevice(SpiBusId, chipSelectLine);
#endif
Thread.Sleep(500);
while (true)
{
for (byte registerIndex = 0; registerIndex <= 0x42; registerIndex++)
{
byte registerValue = sx127XDevice.RegisterReadByte(registerIndex);
Debug.WriteLine($"Register 0x{registerIndex:x2} - Value 0X{registerValue:x2}");
}
Debug.WriteLine("");
Thread.Sleep(10000);
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
}
#if NETDUINO3_WIFI || ST_STM32F769I_DISCOVERY
static int PinNumber(char port, byte pin)
{
if (port < 'A' || port > 'J')
throw new ArgumentException();
return ((port - 'A') * 16) + pin;
}
#endif
}
}
There is some SparkFun LoRa Gateway-1-Channel (ESP32) specific configuration to map the Serial Peripheral Interface(SPI) pins and an additional NuGet for ESP32 has to be added. For the initial versions I have not used more advanced .NET nanoFramework functionality like SpanByte.
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