XIAO ESP32S3
A compact development board by Seeed Studio featuring the ESP32-S3, suitable for wearable and space-constrained applications.
XIAO ESP32S3 Pinout
14 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | D0A0GPIO1 | safe | adc · touch · pwm | |
| 2 | 2 | D1A1GPIO2 | safe | adc · touch · pwm | |
| 3 | 3 | D2A2GPIO3 | strapping | adc · touch · pwm | |
| 4 | 4 | D3A3GPIO4 | safe | adc · touch · pwm | |
| 5 | 5 | D4A4SDAGPIO5 | safe | adc · touch · pwm · i2c | |
| 6 | 6 | D5A5SCLGPIO6 | safe | adc · touch · pwm · i2c | |
| 7 | 43 | D6TXGPIO43 | uart | uart · pwm | |
| 8 | - | 5V | power | - | 5V power input/output |
| 9 | - | GND | ground | - | |
| 10 | - | 3V3 | power | - | 3.3V power |
| 11 | 9 | D10A10MOSIGPIO9 | strapping | adc · touch · pwm · spi | |
| 12 | 8 | D9A9MISOGPIO8 | safe | adc · touch · pwm · spi | |
| 13 | 7 | D8A8SCKGPIO7 | safe | adc · touch · pwm · spi | |
| 14 | 44 | D7RXGPIO44 | uart | uart · pwm |
Start with these
7 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
4 pins · 4 things to knowD2GPIO3 Bootstrapping pin (controls JTAG signal source) Strapping
Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface.
D6GPIO43 UART0 transmit pin (U0TXD), default serial console TX UART
Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0).
D10GPIO9 General-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD) Other
IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet lists it as a priority-2 pin ("can be freely used without restrictions"), so it is only taken if your board wires flash, an SD card or a display to FSPI.
D7GPIO44 UART0 receive pin (U0RXD), default serial console RX UART
Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip.
The XIAO ESP32S3 pinout brings out 14 pins at a 2.54 mm pitch - 11 usable GPIO alongside the 5V, GND and 3V3 power rails.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO5 and SCL on GPIO6; the SPI bus (MOSI, MISO, SCK) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
Beyond plain digital I/O you get 9 ADC-capable pins for sensors and battery monitoring, PWM on every GPIO and 9 capacitive-touch inputs.
4 of the exposed pins carry boot-time or system duties on the ESP32-S3 (D2, D6, D10 and 1 more) - check the guidance above before wiring anything to them. D0, D1, D3, D4 and 3 more are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: XIAO_ESP32S3 USB CDC On Boot: Enabled Flash Size: 8MB (64Mb) Flash Mode: DIO PSRAM: OPI PSRAM Partition Scheme: Default with spiffs (3MB APP/1.5MB SPIFFS) Upload Speed: 921600
// blink the onboard user LED
void setup() {
pinMode(21, OUTPUT);
}
void loop() {
digitalWrite(21, HIGH); delay(500);
digitalWrite(21, LOW); delay(500);
}[env:xiao-esp32s3]
platform = espressif32
board = seeed_xiao_esp32s3
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_opi
build_flags = -DBOARD_HAS_PSRAMseeed_xiao_esp32s3 - or type it after board =.esp32:
board: seeed_xiao_esp32s3
variant: esp32s3
framework:
type: esp-idf
psram:
mode: octal
speed: 80MHz
# blink - GPIO21
output:
- platform: gpio
pin: 21
id: led_out
light:
- platform: binary
name: "LED"
output: led_outseeed_xiao_esp32s3 (same ids as PlatformIO).esptool.py --chip esp32s3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Good to know
board-specific quirks worth 60 seconds
We ran a XIAO ESP32S3 on the bench with arduino-esp32 3.3.11 and PlatformIO, reading the results back over its native USB serial port. ESP.getPsramSize() reports 0 on the default Arduino menu, 8388608 bytes with Tools > PSRAM > OPI PSRAM, and about 8 MB from PlatformIO's seeed_xiao_esp32s3 board definition with no extra flags. Flash reports 8388608 bytes; the chip identifies as ESP32-S3 revision v0.2. The user LED…
We ran a XIAO ESP32S3 on the bench with arduino-esp32 3.3.11 and PlatformIO, reading the results back over its native USB serial port.
ESP.getPsramSize()reports 0 on the default Arduino menu, 8388608 bytes with Tools > PSRAM > OPI PSRAM, and about 8 MB from PlatformIO'sseeed_xiao_esp32s3board definition with no extra flags.- Flash reports 8388608 bytes; the chip identifies as ESP32-S3 revision v0.2.
- The user LED is GPIO21 and lights when the pin is driven LOW.
- Our box contained a 2.4 GHz FPC antenna labelled A-02.
Not tested here: deep-sleep current, and the camera and microphone, which belong to the Sense variant.
The PSRAM is octal (OPI) and off by default in Arduino IDE. Set Tools → PSRAM → "OPI PSRAM" or ESP.getPsramSize() reports 0 and large allocations fail. In PlatformIO the seeed_xiao_esp32s3 board definition enables it (it ships -DBOARD_HAS_PSRAM and a qio_opi memory type); in ESPHome add psram: mode: octal. With PSRAM disabled the sketch still builds and runs - ESP.getPsramSize() simply returns 0 - so check it…
The PSRAM is octal (OPI) and off by default in Arduino IDE. Set Tools → PSRAM → "OPI PSRAM" or ESP.getPsramSize() reports 0 and large allocations fail. In PlatformIO the seeed_xiao_esp32s3 board definition enables it (it ships -DBOARD_HAS_PSRAM and a qio_opi memory type); in ESPHome add psram: mode: octal.
With PSRAM disabled the sketch still builds and runs - ESP.getPsramSize() simply returns 0 - so check it at boot before you allocate a frame buffer.
Gallery
4 photos
Downloads
Free for non-commercial use, credit espboards.dev · License
Board illustration
The bare XIAO ESP32S3 board drawn to scale at 21 × 17.8 mm, with no pin labels on it. Made for slide decks, wiring diagrams and project write-ups where a photo is too busy. Take the scalable SVG for print or editing, the high-resolution PNG to drop straight in, or the transparent PNG when you need it with no background behind it.
Pinout diagram
Every pin on both sides of the board with its functions, drawn by ESPboards from the ESP32-S3 Series Datasheet v2.2 - the same sheet shown at the top of this page. The PNG is a high-resolution image for screens, the SVG is vector so it stays sharp at any size, and the PDF is laid out to print on A4 or Letter.
Yours to use, share and adapt for non-commercial work, as long as you credit espboards.dev - the full terms and ready-made credit lines are here.
Specifications
ESP32-S3 · 21 × 17.8 mm · vs other ESP32 chips →Dimensions
About this board
At 21 × 17.8 mm it's among the smallest boards in the whole ESP32 family.
Inside sits the ESP32-S3 - a dual-core Xtensa with vector extensions suited to AI workloads.
At $7.49 it's cheaper than most ESP32-S3 boards, which usually run around $29.
The small footprint costs pins: 11 GPIO are broken out, versus 23 or so on a full-size board.
Around the module: 8MB (OPI) PSRAM, battery charging via Solder pads, status LEDs (User, Charge) and Reset/Boot buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S3 boards.
The XIAO ESP32S3 is Seeed Studio's ESP32-S3 in the XIAO form factor: a 21 x 17.8 mm board built around an ESP32-S3R8 (dual-core Xtensa LX7 at up to 240 MHz, 8 MB PSRAM in the package) with 8 MB flash, USB-C, and a U.FL connector for the antenna that ships in the box. The PSRAM is what separates it from the XIAO C3 and C6, neither of which has any: 8 MB for camera frame buffers, audio buffers and TinyML models, instead of just the 512 KB of SRAM inside the chip.
Battery support is built in: solder pads for a 3.7 V lithium cell, an onboard charger at 50 mA (fast) / 3.8 mA (trickle), a red charge LED, a user LED on GPIO21 that lights when the pin is driven LOW, and a typical deep-sleep draw of 14 µA. The same board with an OV3660 camera, a digital microphone and a microSD slot on an expansion board that plugs onto the B2B connector at the bottom edge is sold as the XIAO ESP32S3 Sense; the Plus goes to 16 MB of flash and adds nine more GPIOs on back-side pads.
Programming runs over the S3's native USB - there is no separate serial chip - and arduino-esp32 lists the board as XIAO_ESP32S3 (set Tools → PSRAM to "OPI PSRAM"). Boards ship without pin headers, so Seeed also sells a pre-soldered variant with them fitted.
- Dual-core Xtensa LX7 at up to 240 MHz
- Supports WiFi 4 (802.11 b/g/n), Bluetooth 5.0 LE and Bluetooth Mesh
- Ultra-small size (21x17.8 mm)
Where to buy
prices are typical street pricesResources
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