Firmware Structure & Patterns#
Making code predictable. Embedded firmware runs without an operating system to manage execution, allocate resources, or recover from errors. The firmware is the system β it decides what runs, when, and in what order. Structure matters more here than in application software because there is no safety net: a mishandled interrupt or a missed state transition can lock up the system or produce silent, intermittent failures.
The key patterns in bare-metal firmware β startup sequences, interrupt-driven I/O, and state machines β exist because they solve real problems: how to initialize hardware in the right order, how to respond to events without busy-waiting, and how to manage complex behavior without spaghetti code. These patterns aren’t academic; they’re the difference between firmware that works reliably and firmware that works until it doesn’t.
What This Section Covers#
- Startup & Initialization β Vector table, startup code, C runtime initialization, and main loop patterns: what happens between power-on and the first line of application code.
- Interrupts β Priority levels, latency, jitter, nesting, and ISR design rules: the core mechanism for real-time response.
- State Machines & Event Loops β Cooperative scheduling, event-driven design, and superloop vs dispatch patterns: organizing firmware behavior.