Zephyr Basic

You can build and flash a Hello World. Now learn the three systems that underpin every real Zephyr application: Kconfig (what gets compiled), devicetree (what hardware exists), and the driver model (how you talk to it).

Prerequisites

• Completed How to Start — working west build
• ESP32 DK or equivalent supported board

What's in this section

Page	What you'll learn
How to Find the API You Need	Quick lookup: GPIO, I2C, SPI, UART, ADC, PWM, threads, timers, semaphores
Meet the ESP32-S3-DevKitC	The board used for all examples — specs and board target
Writing Overlays	Add sensors and peripherals to your application
WS2812 RGB LED	Drive the built-in RGB LED using the Zephyr LED strip API
Threads	Run Hello World and WS2812 concurrently — your first multi-threaded firmware

Core mental model

prj.conf          →  what is compiled
.overlay          →  what hardware exists
application code  →  what the firmware does

These three files are the skeleton of every Zephyr project. Master them here, apply them forever.

info

Devicetree is the part most engineers find confusing. The Common Mistakes page was written from real debugging sessions — read it before you need it.