Embedded Systems
Embedded software runs on hardware that was never meant to run much of anything: a few hundred kilobytes of flash, no operating system by default, hard real-time deadlines a missed interrupt can blow, and a physical world on the other side of every GPIO pin. This section covers that discipline end to end — Cortex-M architecture and the bare-metal fundamentals, peripherals and interrupt-driven drivers, RTOS concepts (FreeRTOS and Zephyr), the point at which embedded Linux becomes the right answer instead of an RTOS, and the safety, security, and lifecycle concerns that separate a prototype from a shippable product.
It does not re-teach material that already has a home elsewhere on this site. Bus protocols,
general interrupt theory, scheduling theory, CPU architecture, and bit manipulation are covered
in depth under computer-science/; embedded pages link out to that material and add the
register-level and Cortex-M-specific parts on top, rather than repeating it.
Right now this landing page is the only page here — that is why the sidebar shows just
"Overview". The first content folders, 00-overview through 04-bare-metal-programming, are
being written next and will cover the material described below. Everything from
05-peripherals-and-drivers onward is planned but does not exist yet. If you came here looking
for a specific topic and it is not in the sidebar, it has not been published yet — nothing is
missing or broken.
The section is sixteen numbered folders, 00 through 15, each self-contained around one
theme — numeric prefixes only order them on disk, the sidebar label comes from each folder's
_category_.json. The full folder map (one row per folder, phrased as the question it answers)
and the reasoning behind the "link out to computer-science/ instead of repeating it" policy
live on How This Section Is Organised — this
page stays a short index; that one is the expanded reference.
Sections
| Folder | Covers |
|---|---|
📖 00-overview | What "embedded" means as a discipline, the microcontroller/microprocessor/SoC distinction, the landscape of architectures and vendors, bare-metal vs. RTOS vs. Linux, and a glossary |
🔧 01-hardware-foundations | Choosing hardware, schematics and board basics, power and reset behaviour, and what a datasheet actually tells you |
🧠 02-processor-architecture | The Cortex-M register model, memory map and bit-banding, and the pipeline and instruction-set concerns specific to microcontroller cores |
🛠️ 03-toolchain-and-build | Cross-compilers, CMake for embedded, linker scripts, ELF/map files, and the build pipeline from source to flashable image |
⚡ 04-bare-metal-programming | Startup code, vector tables, register-level programming, critical sections, and your first bare-metal blink |
🔌 05-peripherals-and-drivers | GPIO, UART/SPI/I2C in depth, DMA, external memory, and flash/EEPROM emulation |
⏱️ 06-interrupts-timing-and-real-time | The NVIC, timing determinism, scheduling theory as it applies to interrupts, and what breaks determinism on cores with caches |
🧵 07-rtos | Task and scheduling concepts, synchronization primitives, FreeRTOS, and Zephyr |
📡 08-connectivity-and-protocols | USB device stacks, Ethernet and TCP/IP on constrained devices, and wireless connectivity |
🔋 09-low-power-design | Sleep modes, power budgeting, and low-power peripheral design |
🐧 10-embedded-linux | When Linux is the right call, the boot chain, device drivers, and build systems (Yocto, Buildroot) |
🐞 11-debugging-and-testing | JTAG/SWD, hardfault debugging, unit testing firmware, and hardware-in-the-loop testing |
🛡️ 12-safety-and-reliability | IEC 61508, ISO 26262, DO-178C, and IEC 62304 — structure, intent, and engineering consequences, not the normative text |
🔒 13-security | Secure boot, TrustZone-M, secure communication on MCUs, and firmware update security |
♻️ 14-firmware-lifecycle | Versioning, OTA updates, field diagnostics, and long-term maintenance of shipped firmware |
🧩 15-languages-and-practice | Firmware architecture and layering, embedded Rust, MicroPython, and machine learning on microcontrollers |
00-overview through 02-processor-architecture are published, so their row links straight to
the folder's first page; 03 onward stay plain text until their tasks land (folders 03–04 land
later in this same phase, 05–15 in Phases 2 and 3).
Four learning paths
These describe a reading order through folders and pages by name; they are not yet links, because most of the target pages do not exist yet. Once a target page is published, the navigation gets wired up so you can click through directly — for now, use the sidebar or search to find a folder once it appears.
| Path | Suggested order | What it gets you |
|---|---|---|
| Day one | 00-overview (what embedded means) → 01-hardware-foundations (what hardware to buy) → 04-bare-metal-programming (your first bare-metal blink) → then back to 02-processor-architecture and 03-toolchain-and-build for why it worked | A blinking LED before the theory, then the theory that explains it — the fastest way to stay motivated as a beginner |
| I have a board and nothing works | 01-hardware-foundations → 03-toolchain-and-build → 04-bare-metal-programming → 11-debugging-and-testing | A troubleshooting path from "is the board even powered" through toolchain issues to systematic hardfault debugging |
| I'm building a product | 04-bare-metal-programming → 05-peripherals-and-drivers → 07-rtos → 09-low-power-design → 14-firmware-lifecycle | The path from a working prototype to something with drivers, a scheduler, a power budget, and an update story |
| I'm moving to Linux | 02-processor-architecture → 10-embedded-linux → 11-debugging-and-testing | What changes when the target has an MMU and runs Linux instead of bare metal or an RTOS |
Master reference list
A short list of sources worth owning or bookmarking, curated rather than exhaustive. Individual
pages cite the primary, authoritative source for their specific claims (an Arm architecture
reference, a vendor reference manual, docs.kernel.org, an RFC); this list is for the reader who
wants to go deeper than any one page.
Books
- Joseph Yiu, The Definitive Guide to Arm Cortex-M3 and Cortex-M4 Processors (and the companion …Cortex-M0 and Cortex-M0+ edition) — the reference for the core itself: registers, exception model, and the instruction set, written by an Arm architect.
- Elecia White, Making Embedded Systems (O'Reilly) — the best single first book on the discipline as a whole, not just the chip.
Courses, blogs, and video
- Memfault's Interrupt blog (interrupt.memfault.com) — consistently the best current writing on firmware debugging, fault analysis, and build tooling.
- Bootlin's free training materials (bootlin.com/training) — embedded Linux, kernel, and Yocto training slides and labs, released under CC BY-SA.
- Nordic DevAcademy (academy.nordicsemi.com) — Bluetooth Low Energy done properly, from a silicon vendor with no reason to hand-wave the hard parts.
- Ben Eater (eater.net and YouTube) — signalling and bus protocols built up from first principles on a breadboard; unmatched for building real intuition about what a scope is showing you.
Vendor and project documentation
- Arm Developer documentation — architecture reference manuals and processor technical reference manuals.
- Zephyr Project documentation — devicetree, Kconfig, and the
westtool. - FreeRTOS — kernel documentation and API reference.
- The Linux kernel documentation — driver APIs and subsystem guides, relevant once a target moves to embedded Linux.
Where a page below draws on a source that is paywalled or a purchase (the safety standards in
particular — IEC 61508, ISO 26262, DO-178C, and IEC 62304 are all paywalled documents), its
## References section says so rather than linking around the cost.