LCC Fusion Podcast – Fusion Hardware Architecture Overview
In this LCC Fusion podcast episode, Nelson and Harrison step back from individual cards and devices and look at the big picture:
how Fusion’s open-source design, tiered hardware architecture, and modular bus system come together to form a flexible, educational, and expandable platform for layout control.
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This episode explains why Fusion was created, how the architecture works, and why the system grows cleanly without rewiring or redesign.
Watch the Podcast
AI-Assisted Production Notice
This podcast uses AI-generated voices based on the author's guidance, notes, and technical material. The goal is to present the information clearly and consistently, and to keep it easy to update as the LCC Fusion Project evolves.
All technical content, explanations, and project decisions are human-authored.
Why Fusion Was Created
The episode opens with a key question from Nelson:
“Why make all of this open-source? Why not just build a commercial product?”
Harrison explains that Fusion was built for:
- education
- DIY electronics
- STEM-style learning inside the model railroad hobby
- and for hobbyists who want to understand the electronics running their layout
All schematics, PCB files, and firmware are public.
Anyone can study it, build it, or even design new cards.
Fusion’s open-design philosophy is fundamental — not optional.
The Fusion Architecture: A Three-Tier Model
The podcast breaks the system into three clear tiers:
🧠 Tier 1 — The Node Card
The processor.
Runs logic, talks CAN, and defines the type of node.
Fusion already has three different Node boards, each based on a different ESP32 family.
⚙️ Tier 2 — The I/O Cards
Function-specific cards that do the actual work:
Turnouts, Signals, Detection, Audio, Sensors, PWM, etc.
More than 10 different I/O cards already exist.
🔌 Tier 3 — Breakout Boards + Devices
The bridge to the real world.
Breakouts adapt the I/O card signals to motors, LEDs, coils, servos, and sensors.
A single card often supports multiple breakout boards — for example, the Turnout Card works with stall motors, servos, twin-coil machines, and relay-driven systems.
Nelson summarizes it perfectly:
“Brains → Function → Devices.”
Fusion Busses: Simple and Purpose-Built
The podcast also takes time to explain the three busses that make Fusion clean and scalable:
- CAN Bus — connects nodes across the layout
- Node Bus — the backplane that connects a Node to all cards in its cluster
- COMM Bus (I²C) — short-range communication used inside the cluster
Harrison explains how these three busses each have one job, keeping the architecture clean and avoiding interference between layers.
Modeled After Desktop Computer Architecture
Fusion’s hardware design draws directly from 30+ years of PC architecture:
- standard card form factors
- a consistent backplane (like ATX)
- plug-in I/O cards (like PCI/PCIe)
- breakouts acting like purpose-specific adapters
This keeps the system:
- predictable
- expandable
- easy to extend with new hardware
Just like building a computer.
Why Tiers Matter
Nelson asks a key question:
“Why bother with separate tiers? Why not one big board?”
The answer:
tiers keep Fusion expandable.
You can create:
- a new Node Card
- a new I/O Card
- a new breakout board
…and everything still works without changing the Node, Hub, or wiring model.
Fusion grows horizontally — not in complexity.
Work in Progress (Pre-GA)
While the architecture is complete, the project is still in active development:
- new revisions of Node Cards
- new I/O cards and breakout boards
- firmware improvements
- documentation being expanded
- not yet GA — early-access for builders and contributors
The open-source model means the community shapes the system as it grows.
Summary
This episode provides a wide-angle view of how Fusion fits together:
- Open-source at every level
- A clean, three-tier architecture
- A simple and intentional bus structure
- Standardized card form factors
- Breakout boards that simplify wiring
- A platform designed for learning, building, and future expansion
Fusion’s architecture is built to last — and built to grow.
Downloads and Documentation
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Full LCC Fusion Documentation: https://patfleming.github.io/LccFusionProject/
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GitHub Repository: https://github.com/patfleming/LccFusionProject
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LCC Fusion Podcasts Playlist: https://www.youtube.com/playlist?list=PLg49NFDgDCLRS7j30iTitaWUlfIdiw0Wx