$ show mcci-catena/arduino-lorawan
This is a high-level C++ library for building LoRaWAN end-devices on Arduino-compatible platforms. It wraps the MCCI LMIC stack and provides a structured API for OTAA/ABP provisioning, sending uplinks, receiving downlinks, link-check management, and persistent session-state save/restore. The library supports nine network operators (TTN, Actility, Helium, ChirpStack, Generic, machineQ, Senet, Senra, Swisscom) across eight LoRaWAN regions, selected at compile time via preprocessor macros. The architecture uses a two-level inheritance hierarchy: an abstract `Arduino_LoRaWAN` base class, network-specific base classes, and region-specific concrete classes. The LMIC C callback `onEvent()` is routed through a singleton to `DispatchEvent()`, which drives a standard event processor and up to four registered listeners. Application code subclasses a concrete network/region class and overrides virtual methods for provisioning and persistence. Key entry points are `begin()`, `loop()`, `SendBuffer()`, `RegisterListener()`, and `SetLinkCheckMode()`. The session-state subsystem is notably sophisticated: it serializes frame counters, channel masks, band duty-cycle state, and MAC parameters into versioned, tagged structures that can be stored in arbitrary non-volatile memory and restored after reboot. The code is generally well-structured and professional, with clean separation of concerns and careful handling of LMIC internals. However, the repository contains many near-empty per-network/per-region boilerplate files, and the CI pipeline still relies on Travis CI with an old Arduino IDE version. There are no unit tests; regression coverage comes from compile-testing example sketches across multiple boards and regions. The library is actively maintained, but release metadata (library.properties vs. header version) and CI infrastructure lag behind the code itself.
The LLM identified 4 files worth highlighting for reuse:
Defines templated channel-mask structures for EU-like (16-channel) and US-like (72/96-channel) LoRaWAN regions. These self-contained templates pack frequencies into 24-bit fields, manage band assignments, and provide enable/disable operations. They are versioned with tagged headers and could be extracted for any LoRaWAN channel-plan implementation.
Implements full capture and restoration of LMIC MAC state, including frame counters, channel masks, band duty-cycle timers, RX parameters, and MAC command acknowledgements. It validates saved state against the current region and country before applying it, and uses tagged versioned structures for forward compatibility. This is a strong reference pattern for saving and restoring radio-stack state in resource-constrained devices.
Uses SFINAE to detect whether the Arduino `Serial` object has a `dtr()` method, falling back to a boolean conversion check when it does not. This solves a common portability problem across different Arduino cores and is a clean, reusable compile-time technique for feature detection in C++.
Provides a fixed-size ring-buffer event log that defers serial output until the radio is idle, avoiding blocking inside LMIC callbacks. Events are stored with timestamps and client data, and formatting is done via callback functions. This is a reusable non-blocking logging pattern for time-constrained embedded systems.