Uputronics Raspberry Pi+ LoRa(TM) Expansion Board

The second package to arrive was a Raspberry Pi+ LoRa(TM) Expansion Board populated with HopeRF 434MHz & 915MHz modules. It was in a small cardboard box with bolts+spacers and had a small set of printed instructions.

The shield has four user controlable Light Emitting Diodes(LED) connected to General Purpose Input Output(GPIO) pins which will be useful  for providing feedback when trying to debug faults etc..

uputronicsPiPlusHelp

Some of the pin numbers are also printed on the shield silk screen.UputronicsRPIPlusShield
This time the first step was to check the pin assignments of the 4 LEDs

//---------------------------------------------------------------------------------
// Copyright (c) September 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.UputronicsRPIPlusLed
{
	using System;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Gpio;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
			GpioController gpioController = GpioController.GetDefault();

			GpioPin ce01LedPin = gpioController.OpenPin(5);
			ce01LedPin.SetDriveMode(GpioPinDriveMode.Output);
			ce01LedPin.Write(GpioPinValue.Low);

			GpioPin ceo2LedPin = gpioController.OpenPin(21);
			ceo2LedPin.SetDriveMode(GpioPinDriveMode.Output);
			ceo2LedPin.Write(GpioPinValue.High);

			GpioPin lanLedPin = gpioController.OpenPin(6);
			lanLedPin.SetDriveMode(GpioPinDriveMode.Output);
			lanLedPin.Write(GpioPinValue.Low);

			GpioPin internetLedPin = gpioController.OpenPin(13);
			internetLedPin.SetDriveMode(GpioPinDriveMode.Output);
			internetLedPin.Write(GpioPinValue.High);

			while (true)
			{
				if (ce01LedPin.Read() == GpioPinValue.High)
				{
					ce01LedPin.Write(GpioPinValue.Low);
				}
				else
				{
					ce01LedPin.Write(GpioPinValue.High);
				}

				if (ceo2LedPin.Read() == GpioPinValue.High)
				{
					ceo2LedPin.Write(GpioPinValue.Low);
				}
				else
				{
					ceo2LedPin.Write(GpioPinValue.High);
				}

				if (lanLedPin.Read() == GpioPinValue.High)
				{
					lanLedPin.Write(GpioPinValue.Low);
				}
				else
				{
					lanLedPin.Write(GpioPinValue.High);
				}

				if (internetLedPin.Read() == GpioPinValue.High)
				{
					internetLedPin.Write(GpioPinValue.Low);
				}
				else
				{
					internetLedPin.Write(GpioPinValue.High);
				}

				Thread.Sleep(500);
			}
		}
	}
}

I think there is a small issue with the internet LED it should be GPIO13 (which matches the pin number)

The next step was to get the Serial Peripheral Interface (SPI) interface for both modules working.

//---------------------------------------------------------------------------------
// Copyright (c) September 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.UputronicsRPIPlusSPI
{
	using System;
	using System.Diagnostics;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Spi;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
#if CS0
			const int chipSelectPinNumber = 0;
#endif
#if CS1
			const int chipSelectPinNumber = 1;
#endif
			SpiController spiController = SpiController.GetDefaultAsync().AsTask().GetAwaiter().GetResult();
			var settings = new SpiConnectionSettings(chipSelectPinNumber)
			{
				ClockFrequency = 500000,
				Mode = SpiMode.Mode0,   // From SemTech docs pg 80 CPOL=0, CPHA=0
			};
			SpiDevice Device = spiController.GetDevice(settings);

			while (true)
			{
				byte[] writeBuffer = new byte[] { 0x42 }; // RegVersion
				byte[] readBuffer = new byte[1];

				// Read the RegVersion silicon ID to check SPI works
				Device.TransferSequential(writeBuffer, readBuffer);

#if CS0
				Debug.WriteLine("CS0 Register RegVer 0x{0:x2} - Value 0X{1:x2} - Bits {2}", writeBuffer[0], readBuffer[0], Convert.ToString(readBuffer[0], 2).PadLeft(8, '0'));
#endif
#if CS1
				Debug.WriteLine("CS1 Register RegVer 0x{0:x2} - Value 0X{1:x2} - Bits {2}", writeBuffer[0], readBuffer[0], Convert.ToString(readBuffer[0], 2).PadLeft(8, '0'));
#endif
				Thread.Sleep(10000);
			}
		}
	}
}

Like the other uputronics shield I have tested this appears not to have the reset line of the RFM9X connected.

The output confirmed the code worked with both CS0 and CS1 defined

CS0 Register RegVer 0x42 - Value 0X12 - Bits 00010010
CS0 Register RegVer 0x42 - Value 0X12 - Bits 00010010
CS0 Register RegVer 0x42 - Value 0X12 - Bits 00010010
CS0 Register RegVer 0x42 - Value 0X12 - Bits 00010010

 

CS1 Register RegVer 0x42 - Value 0X12 - Bits 00010010
CS1 Register RegVer 0x42 - Value 0X12 - Bits 00010010
CS1 Register RegVer 0x42 - Value 0X12 - Bits 00010010

Would have been more useful to read RegFrMsb = 0x06, RegFrMid = 0x7, and RegFrLsb = 0x08 so I could see the different default frequencies of the two HopeRF modules. The next step is to build support for this shield into my RFM9X.IoTCore library.

Uputronics Raspberry PiZero LoRa(TM) Expansion Board

During the week another couple of Raspberry PI2/3/Zero shields arrived from uputronics. The two Raspberry PiZero LoRa(TM) Expansion Boards had arrived earlier so I unpacked them first. They were in small cardboard boxes with bolts+spacers and had a small set of printed instructions which was quite professional.uputronicsPiZeroLoRaHelp.png
These shields also have a switch for configuring the chip select line which is quite a neat feature and means they can be stacked. Unlike the other shields I have tested these appear not to have the reset line of the RFM9X connected.

UputronicsRPIZeroShield

The first step was to get the SPI connectivity sorted

//---------------------------------------------------------------------------------
// Copyright (c) August 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.UputronicsRPZeroSPI
{
	using System;
	using System.Diagnostics;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Spi;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
#if CS0
			const int chipSelectPinNumber = 0;
#endif
#if CS1
			const int chipSelectPinNumber = 1;
#endif
			SpiController spiController = SpiController.GetDefaultAsync().AsTask().GetAwaiter().GetResult();
			var settings = new SpiConnectionSettings(chipSelectPinNumber)
			{
				ClockFrequency = 500000,
				Mode = SpiMode.Mode0,   // From SemTech docs pg 80 CPOL=0, CPHA=0
			};
			SpiDevice Device = spiController.GetDevice(settings);

			while (true)
			{
				byte[] writeBuffer = new byte[] { 0x42 }; // RegVersion
				byte[] readBuffer = new byte[1];

				// Read the RegVersion silicon ID to check SPI works
				Device.TransferSequential(writeBuffer, readBuffer);

				Debug.WriteLine("Register RegVer 0x{0:x2} - Value 0X{1:x2} - Bits {2}", writeBuffer[0], readBuffer[0], Convert.ToString(readBuffer[0], 2).PadLeft(8, '0'));

				Thread.Sleep(10000);
			}
		}
	}
}

The output confirmed the code worked with both CS0 and CS1 defined

Register RegVer 0x42 - Value 0X12 - Bits 00010010
Register RegVer 0x42 - Value 0X12 - Bits 00010010
Register RegVer 0x42 - Value 0X12 - Bits 00010010
The program '[2144] backgroundTaskHost.exe' has exited with code -1 (0xffffffff).

The shield has two onboard Light Emitting Diodes (LEDs) so I wrote a simple test application to flash them alternately.

//---------------------------------------------------------------------------------
// Copyright (c) July 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.UputronicsRPZeroLed
{
	using System;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Gpio;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
			GpioController gpioController = GpioController.GetDefault();
			GpioPin dataLedPin = gpioController.OpenPin(13);
			dataLedPin.SetDriveMode(GpioPinDriveMode.Output);
			dataLedPin.Write(GpioPinValue.Low);
			GpioPin linkLedPin = gpioController.OpenPin(6);
			linkLedPin.SetDriveMode(GpioPinDriveMode.Output);
			linkLedPin.Write(GpioPinValue.High);

			while (true)
			{

				if (dataLedPin.Read() == GpioPinValue.High)
				{
					dataLedPin.Write(GpioPinValue.Low);
				}
				else
				{
					dataLedPin.Write(GpioPinValue.High);
				}

				if (linkLedPin.Read() == GpioPinValue.High)
				{
					linkLedPin.Write(GpioPinValue.Low);
				}
				else
				{
					linkLedPin.Write(GpioPinValue.High);
				}

				Thread.Sleep(500);
			}
		}
	}
}

The two LEDs are labelled Data and Link but the pin numbers in the documentation were for an RPI Zero so didn’t match the ones I had to configure in code for my RPI3.

Overall the shield was professionally packaged and appears well engineered.

Elecrow Lora RFM95 IOT Board for RPI

For the example code so far I had been using the Dragino LoRa GPS HAT for Raspberry PI which after looking at the schematic (to figure out how the chip select line was connected) worked pretty well.

I had also purchased a Lora RFM95 IOT Board for RPI from Elecrow and was keen to get that working for applications which don’t require Global Positioning System (GPS) support.

The RFM95 chip select line is connected to pin 26 (GPIO7), the reset line to pin 15(GPIO22) and the interrupt line (RFM96 DIO0) to pin 22(GPIO25).

Lora RFM95 IOT Board for RPI V1.0

The shield had a Light Emitting Diode (LED) connected to General Purpose Input Output (GPIO) 23 so the first step was to get that to flash.

//---------------------------------------------------------------------------------
// Copyright (c) July 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.ElecrowLed
{
	using System;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Gpio;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
			GpioController gpioController = GpioController.GetDefault();
			GpioPin yellowLedPin = gpioController.OpenPin(23);
			yellowLedPin.SetDriveMode(GpioPinDriveMode.Output);

			while (true)
			{
				if (yellowLedPin.Read() == GpioPinValue.High)
				{
					yellowLedPin.Write(GpioPinValue.Low);
				}
				else
				{
					yellowLedPin.Write(GpioPinValue.High);
				}
				Thread.Sleep(500);
			}
		}
	}
}

To confirm I could access the RMF95 registers over the Serial Peripheral Interface (SPI) I read the RegVersion register.

//---------------------------------------------------------------------------------
// Copyright (c) July 2018, devMobile Software
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------------
namespace devMobile.IoT.Rfm9x.ElecrowSPI
{
	using System;
	using System.Diagnostics;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Spi;

	public sealed class StartupTask : IBackgroundTask
    {
		public void Run(IBackgroundTaskInstance taskInstance)
		{
			SpiController spiController = SpiController.GetDefaultAsync().AsTask().GetAwaiter().GetResult();
			var settings = new SpiConnectionSettings(1)	// GPIO7 Elecrow shield
			{
				ClockFrequency = 500000,
				Mode = SpiMode.Mode0,	// From SemTech docs pg 80 CPOL=0, CPHA=0
			};

			SpiDevice Device = spiController.GetDevice(settings);

			while (true)
			{
				byte[] writeBuffer = new byte[] { 0x42 }; // RegVersion
				byte[] readBuffer = new byte[1];

				Device.TransferSequential(writeBuffer, readBuffer);

				byte registerValue = readBuffer[0];
				Debug.WriteLine("Register 0x{0:x2} - Value 0X{1:x2} - Bits {2}", 0x42, registerValue, Convert.ToString(registerValue, 2).PadLeft(8, '0'));

				Thread.Sleep(10000);
			}
		}
	}
}

The debug output confirmed I was reading the right value from the RegVer register

Register 0x42 - Value 0X12 - Bits 00010010
Register 0x42 - Value 0X12 - Bits 00010010
Register 0x42 - Value 0X12 - Bits 00010010
Register 0x42 - Value 0X12 - Bits 00010010

I’m going to unsolder the coil antenna and replace it with a short SMA Extension drop cable so I can connect an external antenna.

ElecrowLoRaShield