M2M LoRaWan Gateway Shield for Raspberry Pi

This morning a 1 Channel LoRaWan Gateway Shield for Raspberry Pi arrived from M2M along with a Low power LoRaWan Node Model A328 and Low power oRaWan Node Model B1284.

First setup to get the LoRaWan Gateway Shield up and running on my Raspberry PI 3.

M2MLoRaShield

No schematics were available so I had to reverse engineer the configuration for the Single Channel LoRaWAN Gateway for my Windows 10 IoT Core setup.

pins configuration in global_conf.json

“pin_nss”: 6,

“pin_dio0”: 7,

“pin_rst”: 0

If you use RPI0, edit single_chan_pkt_fwd.cpp and change eth0 to wlan0.

First step was to confirm I had the chip select line and SPI configuration sorted by reading the RegVersion register.

//---------------------------------------------------------------------------------
// 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.M2MSPI
{
	using System;
	using System.Diagnostics;
	using System.Threading;
	using Windows.ApplicationModel.Background;
	using Windows.Devices.Gpio;
	using Windows.Devices.Spi;

	public sealed class StartupTask : IBackgroundTask
	{
		public void Run(IBackgroundTaskInstance taskInstance)
		{
			GpioPin ChipSelectGpioPin = null;
			const int chipSelectPinNumber = 25;

			SpiController spiController = SpiController.GetDefaultAsync().AsTask().GetAwaiter().GetResult();
			var settings = new SpiConnectionSettings(1)
			{
				ClockFrequency = 500000,
				Mode = SpiMode.Mode0,   // From SemTech docs pg 80 CPOL=0, CPHA=0
			};

			// Chip select pin configuration
			GpioController gpioController = GpioController.GetDefault();
		   ChipSelectGpioPin = gpioController.OpenPin(chipSelectPinNumber);
			ChipSelectGpioPin.SetDriveMode(GpioPinDriveMode.Output);
			ChipSelectGpioPin.Write(GpioPinValue.High);

			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
				ChipSelectGpioPin.Write(GpioPinValue.Low);
				Device.TransferSequential(writeBuffer, readBuffer);
				ChipSelectGpioPin.Write(GpioPinValue.High);
				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 I could read the register

‘backgroundTaskHost.exe’ (CoreCLR: CoreCLR_UWP_Domain): Loaded ‘C:\Data\Users\DefaultAccount\AppData\Local\DevelopmentFiles\M2MSPI-uwpVS.Debug_ARM.Bryn.Lewis\System.Threading.Thread.dll’. Skipped loading symbols. Module is optimized and the debugger option ‘Just My Code’ is enabled.
Register RegVer 0x42 – Value 0X12 – Bits 00010010
Register RegVer 0x42 – Value 0X12 – Bits 00010010

So far the M2M shield looks like a well priced option for my DIY LoRa Gateway deployments.

It arrived promptly and the vendor followed up with sample Arduino code a couple of days after the package shipped.

 

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