--- title: XIAO ESP32-S3 lang: en type: notion tags: - eee - notion - xiao prerequis: - microcontroleur-en - esp32-en aa: [] phases: - concept draft: false source_fr: embarque/mcu/xiao/xiao-esp32-s3.md source_sha256: 4cf98b044b7a51e6cfa138d08786ae9ee62a244bf4575d7c76ef6199dd557253 --- The **XIAO ESP32-S3** is a *stamp-sized* development board (≈ 21 × 17.8 mm) from **Seeed Studio**, built around the [[esp32-en|ESP32]]-S3 chip: two cores at 240 MHz, 8 MB of PSRAM, Wi-Fi and BLE, all on a USB-C board that fits on a fingernail. This page is the board's **route hub**: why this one, which variant to choose, and how to use it on a project by leaning on the pages that already exist. XIAO is a **form factor**, not a chip family: everything about the SoC, the radios and the toolchains is carried by the [[esp32-en|ESP32]] module, and the choice between microcontroller families stays with [[microcontroleur-en|microcontroller]]. ![XIAO ESP32-S3 board and its features: USB-C, U.FL antenna connector, user LED on GPIO21, Boot and Reset buttons, and the power, 11 GPIO, 9 ADC, I²C, SPI and UART groups.|640](/ressources/img/xiao-esp32-s3/brochage.svg) ## Why the XIAO ESP32-S3? You reach for this board when you want the **connectivity and the power of an ESP32 in a minimal footprint**: - **stamp-sized form factor** (≈ 21 × 17.8 mm, castellated edges that mount as an SMD part) — ideal for a wearable object or a compact product; - **ESP32-S3**: two Xtensa LX7 cores at 240 MHz, **8 MB of PSRAM + 8 MB of Flash**, vector instructions for embedded AI; - **Wi-Fi 4 (2.4 GHz) + BLE 5** built in, with a ceramic antenna **and** an external antenna connector; - **native USB-C**: the ESP32-S3 handles USB without an external chip; - **on-board LiPo charging** (battery pads on the back) and a very frugal [[deep-sleep-en|deep sleep]] mode → battery operation. The price of miniaturisation: **only eleven pins** come out on the edges (see below), and the board runs at **3.3 V**: sensors and modules running at 5 V need a level adaptation (see [[niveaux-de-tension-en|logic levels]]). ## Choosing your variant XIAO offers the same form factor on several ESP32 chips. The choice starts from the **project's need**, not from the datasheet. ![Decision tree for choosing a XIAO ESP32 variant: camera or AI leads to the S3 Sense, Matter or Zigbee to the C6, 5 GHz Wi-Fi to the C5, modest needs to the C3, otherwise the S3 by default.|640](/ressources/img/xiao-esp32-s3/variantes.svg) | Variant | Core | RAM / Flash | Radios | Signature peripheral | Choose it if… | | --- | --- | --- | --- | --- | --- | | **ESP32-S3** | Xtensa LX7 ×2, 240 MHz | 8 MB PSRAM / 8 MB | Wi-Fi 4 + BLE 5 | — (reference board) | you want the Wi-Fi + BLE + power balance | | **ESP32-S3 Sense** | same as S3 | 8 MB PSRAM / 8 MB | Wi-Fi 4 + BLE 5 | OV2640/OV3660 camera + microphone + microSD | vision, audio, embedded AI | | **ESP32-C3** | RISC-V, 160 MHz | 400 KB / 4 MB | Wi-Fi 4 + BLE 5 | — | modest needs, minimum consumption | | **ESP32-C6** | RISC-V (HP + LP) | 512 KB / 4 MB | Wi-Fi 6 + BLE 5 + 802.15.4 | Thread / Zigbee / **Matter** | interoperable home automation | | **ESP32-C5** | RISC-V | 512 KB / 4 MB | **dual-band** Wi-Fi 6 (2.4 / 5 GHz) | — | gateway, 5 GHz Wi-Fi | ## Putting it to work on a project Programming this board calls on the same building blocks as any microcontroller: inputs/outputs, communication, wireless, low power. The table below **sends each need to the page that explains it** — to get started, read it top to bottom; otherwise, go straight to what is missing. And to run a project end to end (putting numbers on the needs, choosing, designing, programming, testing), everything is laid out in [[en/embarque/index|building the embedded subsystem]], where the XIAO comes in at the [[choisir-le-materiel-en|choosing the hardware]] step. | Need | Go and see | | --- | --- | | programming in C++ (Arduino) | [[arduino-en\|Arduino]] + [[esp32-arduino-core-en\|ESP32 Arduino core]] | | programming in MicroPython | [[micropython-en\|MicroPython]] | | the GPIO / PWM / ADC basics | [[gpio-en\|GPIO]] · [[pwm-en\|PWM]] · [[adc-en\|ADC]] | | communicating (I²C / SPI / UART) | [[bus-de-communication-en\|communication buses]] | | connecting over Wi-Fi | [[esp32-wifi-en\|ESP32 Wi-Fi]] | | connecting over Bluetooth (BLE) | [[esp32-ble-en\|ESP32 BLE]] | | reacting to an event | [[interruption-en\|interrupt]] · [[timer-en\|timer]] | | saving battery | [[deep-sleep-en\|deep sleep]] + [[esp32-deep-sleep-en\|ESP32 deep sleep]] | | doing several things at once | [[esp32-freertos-en\|FreeRTOS]] | | structuring your code | [[firmware-en\|firmware]] | | trying it without hardware | [[wokwi-en\|Wokwi]] — the XIAO C3, S3 and C6 are simulated there | Three pages cover what is **specific to the board**: the first flashing with [[xiao-prise-en-main-en|getting started]], powering and battery charging with [[xiao-alimentation-en|power]], and the camera/AI version with [[xiao-sense-en|XIAO Sense]]. ## The eleven pins The ESP32-S3 SoC exposes some forty GPIO, but the XIAO form factor brings out only **eleven** of them (D0–D10), plus the power pins. This is the board's number one constraint. | Pad | GPIO | ADC | Touch | "Default" role | | --- | --- | --- | --- | --- | | D0 | GPIO1 | ✓ | ✓ | — | | D1 | GPIO2 | ✓ | ✓ | — | | D2 | GPIO3 | ✓ | ✓ | strapping | | D3 | GPIO4 | ✓ | ✓ | — | | D4 | GPIO5 | ✓ | ✓ | I²C **SDA** | | D5 | GPIO6 | ✓ | ✓ | I²C **SCL** | | D6 | GPIO43 | — | — | UART **TX** | | D7 | GPIO44 | — | — | UART **RX** | | D8 | GPIO7 | ✓ | ✓ | SPI **SCK** | | D9 | GPIO8 | ✓ | ✓ | SPI **MISO** | | D10 | GPIO9 | ✓ | ✓ | SPI **MOSI** | On the power side: **5V** (the USB output, or an input *through a series diode*), **3V3** (regulated output, up to 700 mA), **GND**, and the **B+ / B−** battery pads on the back. A **user LED** is wired to GPIO21, plus a charging LED and the Boot/Reset buttons. > [!warning] Pin pitfalls > - **The D0…D10 silkscreen is not the GPIO number.** In Arduino you can write `D6`, but elsewhere (MicroPython, many libraries) it is the **GPIO** number that is expected, and `D6` means **GPIO43**, not GPIO6. > - **Nine ADC pads only**: D0–D5 and D8–D10. **D6/D7** are reserved for the UART (no analogue), and on the Sense **A11/A12 (GPIO41/42) do no ADC** despite their name. > - **No DAC** on the ESP32-S3, unlike the classic ESP32: for a true analogue output, an external converter or filtered PWM (see [[dac-en|DAC]]). > - **Strapping pins**: the Boot button is on GPIO0, and **D2 (GPIO3)** is a strapping pad: a level forced at start-up can prevent booting or flashing. Keep it free at reset if you can. ## Extending the inputs/outputs Eleven pins runs short fast. The standard answer is an **I/O expander on the [[i2c-en|I²C]] bus**: two wires (SDA on D4, SCL on D5) drive a chip such as the **PCF8574** (8 I/O) or the **MCP23017** (16 I/O), addressable: you can chain several on the same bus. ![Wiring an I/O expander on the XIAO's I²C bus: SDA on D4, SCL on D5, two pull-up resistors to 3V3, and 8 to 16 inputs-outputs coming out of the expander.|640](/ressources/img/xiao-esp32-s3/extendeur-i2c.svg) The other route, with no soldering, is the **XIAO expansion ecosystem**: the *Expansion Base* (OLED screen, RTC, buzzer, microSD reader, Grove connectors) and the **Grove** modules plug straight in and give access to the common peripherals without fine wiring. ## The antenna, internal or external The board carries a **ceramic antenna**, active by default, and an **external antenna connector (U.FL / IPEX)** with an antenna supplied. You plug in the external antenna to gain range: inside an **enclosure** (a metal one especially), **close to a battery or a ground plane**, or for a **long distance**. ![Comparison of the XIAO's internal and external antennas: on the left the built-in ceramic antenna used by default, on the right an external antenna plugged into the U.FL connector for more range.|640](/ressources/img/xiao-esp32-s3/antenne.svg) Two precautions: the U.FL connector is **fragile** (clip and unclip it carefully, holding the connector and not the cable), and the choice is **hardware**, not a software switch. ## Form factor and mounting The **castellated edges** let you solder the XIAO straight onto your own board, like an SMD module: this is the step from **prototype to product** (see [[pcb-en|PCB design]]). With soldered headers, the 2.54 mm pitch stays breadboard- and perfboard-compatible. Power comes in through **USB-C** or through the pads (5V via a diode, or a battery on B+/B−). ## See also - [[esp32-en|ESP32]] — the SoC, the radios, the toolchains (the chip route) - [[microcontroleur-en|Microcontroller]] — an overview of the families and help choosing between them - [[xiao-prise-en-main-en|XIAO — getting started]] — first flashing, buttons, USB - [[xiao-alimentation-en|XIAO — power]] — battery charging, low power - [[xiao-sense-en|XIAO Sense]] — camera, microphone, microSD, embedded AI - [[en/embarque/index|Building the embedded subsystem]] — the project approach from end to end - [[choisir-le-materiel-en|Choosing the hardware]] — the step where the XIAO enters the project - [[wokwi-en|Wokwi]] — simulating the board and its code in the browser, before the hardware - [[i2c-en|I²C]] — the bus for the I/O expander - [[deep-sleep-en|Deep sleep]] — the low-power mode for battery operation