A hands-on, zero-hardware curriculum for learning embedded systems programming.
19 progressive lessons across 4 microcontroller platforms — all runnable in your browser using the free Wokwi simulator. No dev boards, no soldering, no toolchain headaches. Just code, circuits, and deeply annotated explanations.
The comments in the code ARE the lesson. Each sketch explains not just what the code does, but why — down to the register level, with cross-platform comparisons throughout.
- Head to wokwi.com and create a new project
- Select the board for your lesson (ESP32 · STM32 Nucleo · Arduino Uno · Raspberry Pi Pico)
- Paste the lesson's
sketch.inointo the code editor - Switch to the diagram tab and paste
diagram.json - Hit Play ▶ and start learning
No account required. No installs. Works on any machine with a browser.
Xtensa LX6 · 240 MHz · Dual Core · WiFi + Bluetooth · 520 KB SRAM
| # | Lesson | Concepts |
|---|---|---|
| 01 | Blink | GPIO output · register-level vs Arduino abstractions · timing |
| 02 | Button + LED | GPIO input · pull-up resistors · debouncing · non-blocking timing |
| 03 | Serial / UART | UART protocol · baud rate · ADC · command parsing |
| 04 | PWM LED | Pulse Width Modulation · duty cycle · LEDC peripheral |
| 05 | I2C Sensor | I2C bus · device addresses · DHT22 temperature/humidity |
| 06 | Interrupts | Hardware interrupts · ISRs · volatile · IRAM_ATTR · critical sections |
Cortex-M0+ · 48 MHz · Clock Gating · HAL/LL Drivers · AHB/APB Bus
| # | Lesson | Concepts |
|---|---|---|
| 07 | GPIO & HAL | HAL vs direct registers · clock tree · MODER/BSRR · peripheral clocks |
| 08 | Timers & PWM | Hardware timers · prescaler/ARR/CCR · capture/compare · encoder mode |
| 09 | ADC with DMA | DMA transfers · scan mode · continuous conversion · zero-CPU-cost sampling |
| 10 | I2C OLED | I2C on STM32 · SSD1306 display · address scanning · raw byte commands |
ATmega328P · 8-bit · 16 MHz · 2 KB RAM · 32 KB Flash
| # | Lesson | Concepts |
|---|---|---|
| 11 | Port Manipulation | DDRx/PORTx/PINx registers · bitwise ops · single-cycle I/O |
| 12 | Timer Interrupts | Timer1 CTC mode · prescalers · OCR1A · precise periodic interrupts |
| 13 | EEPROM | Non-volatile storage · wear levelling · 100K write-cycle endurance |
| 14 | Watchdog Timer | WDT reset · hang recovery · WDTCSR · production reliability |
RP2040 · Dual Cortex-M0+ · 133 MHz · PIO · 264 KB SRAM
| # | Lesson | Concepts |
|---|---|---|
| 15 | Dual Core | Multicore execution · setup1()/loop1() · hardware FIFO mailbox |
| 16 | PIO | Programmable I/O state machines · WS2812 NeoPixels · custom protocols |
| 17 | ADC & Temp Sensor | Built-in temperature sensor · 12-bit ADC · oversampling techniques |
| 18 | PWM Slices | 8 hardware PWM slices · RGB LED · HSV colour cycling |
| # | Lesson | Concepts |
|---|---|---|
| 19 | Comparison | The same task on all four platforms — GPIO, debounce, interrupts, timing, and memory models compared side-by-side |
By the end of this curriculum, you'll understand:
- GPIO — How pins physically switch between voltage levels
- Registers — Reading/writing hardware control registers directly
- Communication protocols — UART, I2C, SPI fundamentals
- Interrupts — Hardware event handling without polling
- Timers & PWM — Precise timing, waveform generation, motor/LED control
- DMA — Offloading data transfers from the CPU
- Memory constraints — Working within 2 KB RAM (AVR) to 520 KB (ESP32)
- Multicore — Parallel execution on dual-core MCUs
- PIO — Custom hardware I/O protocols (RP2040)
- Watchdog & EEPROM — Production reliability and persistence
- Platform differences — Why the same task looks different on ARM vs AVR vs Xtensa
These MCU families are critical in industry but aren't available in Wokwi:
| Platform | Why It Matters |
|---|---|
| Nordic nRF52/53/91 | Dominant in Bluetooth Low Energy — wearables, asset trackers, hearing aids. nRF9160 adds cellular (LTE-M/NB-IoT). |
| TI MSP430 | Ultra-low-power king — µA-level consumption for battery-powered metering, medical devices, and energy harvesting. |
| Microchip PIC | Decades of legacy across 8/16/32-bit families — automotive, appliances, industrial control. Billions shipped. |
| NXP LPC / i.MX RT | Automotive (CAN/LIN), NFC/RFID, and high-performance real-time. i.MX RT crossover processors blur the MCU/MPU line. |
| Renesas RA/RX/RL78 | #1 MCU vendor by automotive market share. Cortex-M based RA family. Ubiquitous in Japanese automotive and industrial. |
Found a bug in a diagram? Want to add a lesson for a new peripheral? PRs are welcome.
Each lesson should follow the established format:
sketch.ino— Heavily commented code (the comments are the lesson)diagram.json— Valid Wokwi circuit diagram- One clear concept per lesson, building on previous ones
MIT License — see LICENSE for details.
Created by Stuart Hart — built as an open educational resource for anyone learning embedded systems.
From blinking an LED to programming hardware state machines — one lesson at a time.