LoRa KISS Modem

This project implements a KISS (Keep It Simple Stupid) modem for LoRa radios, targeting widely available commercial development boards (e.g., Heltec, RAK, Seeed, ESP32, nRF52840). It bridges a KISS serial interface to a LoRa radio, enabling packet radio applications over long-range wireless links.

Features

• KISS TNC protocol over UART/USB serial
• LoRa radio support (Semtech LR11xx and compatible)
• Zephyr RTOS-based for portability and reliability
• No dynamic memory allocation (static stack/heap usage)
• Designed for low-power, embedded use

Hardware Requirements

• Supported LoRa development board (e.g., Heltec, RAK, Seeed, ESP32, nRF52840)
• LoRa radio module (LR11xx or compatible)
• USB or UART connection to host

Building the Firmware

Prerequisites

• Zephyr SDK
• west (Zephyr meta-tool)
• Board support package for your target board

Steps

1. Initialize Zephyr workspace (if not already):

   west init -l .
   west update
   west zephyr-export
   

2. Build for your board: Replace <board> with your board's Zephyr name (e.g., heltec_wifi_lora32_v2).

   west build -b <board> .
   

   Example:

   west build -b heltec_wifi_lora32_v2 .
   

Flashing the Firmware

1. Connect your board via USB.
2. Flash using west:

   west flash
   

   (You may need to specify --runner or additional options depending on your board.)

Serial Interface

• Default baud rate: 115200
• KISS protocol framing
• Connect to /dev/ttyUSBx or equivalent on your host

Directory Structure

• app/ – Zephyr application code
• drivers/ – LoRa radio drivers (e.g., LR11xx)
• boards/ – Board overlays and configuration
• dts/ – Device tree sources
• zephyr/ – Zephyr RTOS (west workspace)

License

See LICENSE file for details.

References

• KISS TNC Protocol
• Zephyr Project Documentation