RNode Custom Firmware by KC1AWV

This is a customized version of the RNode firmware, designed for use using the Moteino MEGA by LowPowerLab, with the RFM95 LoRa Module.

This work is a derivative of the RNode developed and sold by Mark Qvist. RNode is Copyright by Mark Qvist.

I have no intention of selling or distributing custom RNodes. The assumption here is that you know why you're here, and you know why and how to purchase and build the requisite hardware mentioned in this derivative. Mark Qvist and Steve Miller are not responsible for undesired operation including but not limited to things breaking, catching fire, or collapsing the space-time continuum. You have been warned.

Changes made:

• Config.h pinouts for the RFM95 module installed on the Moteino MEGA
• Refactor .ino code to .cpp (developing using VSCode / PlatformIO)
• ROM.h added custom model E4 (0xE4) for Moteino MEGA board with RFM95 LoRa module
• Utilities.h & ROM.h removed references to Mark Qvist's model A4 and A9 due to pin changes and to prevent bad flashes onto real RNodes

Caveat:

Writing this firmware requires an additional step using rnodeconfigutil, as flashing the firmware to the Moteino MEGA will not write the EEPROM data needed by the device.

It is strongly suggested that you use the customized RNode Configuration tool for Custom RNode Model E4.

RNode Firmware

This is the firmware for RNode, a very flexible LoRa-based communication device. RNode can functions as a:

• A general purpose long-range data radio
• Network adapter for RNS
• LoRa interface for your computer (or any device with a USB or serial port)
• Generic LoRa-based network adapter for your Linux devices
• Packet sniffer for LoRa networks
• LoRa development board
• A LoRa-based KISS-compatible TNC
• A flexible platform for experiementing with LoRa technology

RNode is controlled by a powerful ATmega1284p MCU, and is fully Arduino compatible. You can use this firmware, or it can be programmed any way you like, either from the Arduino IDE, or using any of the available tools for AVR development. This firmware can also be edited and compiled directly from the Arduino IDE.

For adding RNode to your Arduino environment, please see this post.

For configuring an RNode with this firmware, please have a look at the RNode Config Utility.

Current Status

The RNode firmware can be considered stable at this point. If you do find a bug or discover unintended behaviour, please report it as an issue here, so I can fix it!

Operating Modes

RNode can operate in two modes, host-controlled (default) and TNC mode:

• When RNode is in host-controlled mode, it will stay in standby when powered on, until the host specifies frequency, bandwidth, transmit power and other required parameters. This mode can be enabled by using the -N option of this utility. In host-controlled mode, promiscuous mode can be activated to sniff any LoRa frames.

• When RNode is in TNC mode, it will configure itself on powerup and enable the radio immediately. This mode can be enabled by using the -T option of this utility (the utility will guide you through the settings if you don't specify them directly).

USB and Serial Protocol

You can communicate with RNode either via the on-board USB connector, or using the serial pins on the board (labeled RX0 and TX0). RNode uses a standard FTDI USB chip, so it works out of the box without additional drivers in most operating systems.

All communications to and from the board uses KISS framing with a custom command set. RNode also does not use HDLC ports in the command byte, and as such uses the full 8 bits of the command byte is available for the actual command. Please see table below for supported commands.

Command	Byte	Description
Data frame	0x00	A data packet to or from the device
Frequency	0x01	Sets or queries the frequency
Bandwidth	0x02	Sets or queries the bandwidth
TX Power	0x03	Sets or queries the TX power
Spreading Factor	0x04	Sets or queries the spreading factor
Coding Rate	0x05	Sets or queries the coding rate
Radio State	0x06	Sets or queries radio state
Radio Lock	0x07	Sets or queries the radio lock
Device Detect	0x08	Probe command for device detection
Promiscuous	0x0E	Sets or queries promiscuous mode
RX Stats	0x21	Queries received bytes
TX Stats	0x22	Queries transmitted bytes
Last RSSI	0x23	Indicates RSSI of last packet received
Blink	0x30	Blinks LEDs
Random	0x40	Queries for a random number
Firmware Version	0x50	Queries for installed firmware version
ROM Read	0x51	Read EEPROM byte
ROM Write	0x52	Write EEPROM byte
TNC Mode	0x53	Enables TNC mode
Normal Mode	0x54	Enables host-controlled mode
ROM Erase	0x59	Completely erases EEPROM
Error	0x90	Indicates an error

Programming Libraries

Have a look in the "Libraries" folder for includes to let you easily use RNode in your own software.

Here's a Python example:

from RNode import RNodeInterface

def gotPacket(data, rnode):
	print "Received a packet: "+data

rnode = RNodeInterface(
	callback = gotPacket,
	name = "My RNode",
	port = "/dev/ttyUSB0",
	frequency = 868000000,
	bandwidth = 125000,
	txpower = 2,
	sf = 7,
	cr = 5,
	loglevel = RNodeInterface.LOG_DEBUG)

rnode.send("Hello World!")

Promiscuous Mode and LoRa Sniffing

RNode can be put into LoRa promiscuous mode, which will dump raw LoRa frames to the host. Raw LoRa frames can also be sent in this mode, and have the standard LoRa payload size of 255 bytes. To enable promiscuous mode send the "Promiscuous" command to the board, or use one of the programming libraries. You can also use the example program LoRaMon for an easy to use LoRa packet sniffer.