How a whole device is put together on the Uno: a scheduler and state machines, ISRs that only record, drivers behind interfaces, checked settings in EEPROM, error codes and the watchdog, safe updates, and a layered multi-sensor boss.
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7 lessons in 4 chapters, about 7 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator.
An ISR that only records each edge and its time into a ring, a main loop that drains and debounces it, volatile and atomic reads done right, and an overflow counter that tells you when the loop fell behind.
Open it in the simulatorSettings in an envelope: a magic number, a version, a size and a CRC-16, checked field by field at every boot, defaults when anything is off, only changed bytes written, and a watchdog reset to prove it all survives.
Open it in the simulatorHow a device updates itself without ever bricking: A/B slots, an image header with a version, a length and a CRC-32, trial boots that must confirm, automatic rollback, and a minimum version that refuses a perfect copy of old firmware.
Open it in the simulatorEach lesson opens when the one before it is done, and each chapter ends in a project.
A superloop, a scheduler, a machine in a table, and ISRs that only record.
A cooperative scheduler that runs tasks on their own periods, a state machine whose behavior lives in a transition table, and a stopwatch on every pass of loop() that catches a task breaking the one rule.
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An ISR that only records each edge and its time into a ring, a main loop that drains and debounces it, volatile and atomic reads done right, and an overflow counter that tells you when the loop fell behind.
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Drivers behind interfaces, and settings that survive a reset.
A comfort monitor that only talks to a ClimateSensor and a Display interface: a DHT22 driver, an LCD driver, and a scripted fake that plays a heat wave, a dry room and a dead sensor on demand.
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Settings in an envelope: a magic number, a version, a size and a CRC-16, checked field by field at every boot, defaults when anything is off, only changed bytes written, and a watchdog reset to prove it all survives.
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Error codes, fail-safe states, the watchdog, and updates that cannot brick.
A heater controller whose functions return error codes, a policy table that retries or trips a latched fail-safe, and the chip's real watchdog in its two-stage mode: task check-ins, last words saved to EEPROM, then a reset.
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How a device updates itself without ever bricking: A/B slots, an image header with a version, a length and a CRC-32, trial boots that must confirm, automatic rollback, and a minimum version that refuses a perfect copy of old firmware.
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A multi-sensor machine guard built from every layer in the course.
The sensor lab becomes a real device: drivers for an LM35, a Hall switch and a slotted wheel, a scheduler with check-ins, a table-driven machine, checked thresholds in EEPROM, error codes and a latched trip.
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All 7 lessons, in order, each with what it covers. Any of them opens in the editor right away.
Firmware architecture is part of the embedded track, a ladder of courses from zero to expert.
Arduino, ESP32, Raspberry Pi Pico and STM32: pins, timing, buses, motors, WiFi, registers and debugging, every lesson checked on a simulated board.
See every course on the trackEvery lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts.
Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins.
See every kitYes. All 7 lessons of Firmware architecture are free and run in your browser, with nothing to install and no parts to buy before you start.
No. Every lesson runs on a simulated Arduino Uno R3 with its parts on the canvas, and the simulator checks each step as you go. When you want to build it for real, the same wiring and code work on a real board.
About 7 hours: 7 lessons in 4 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off.
Each chapter ends in a project that puts it together: Interrupts and buffers, Configuration and EEPROM and OTA and bootloader concepts.
With "Superloops and state machines", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.