XIAO ESP32S3
A compact development board by Seeed Studio featuring the ESP32-S3, suitable for wearable and space-constrained applications.
Pinout
14 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | D0A0GPIO1 | safe | adc · pwm | |
| 2 | 2 | D1A1GPIO2 | safe | adc · pwm | |
| 3 | 3 | D2A2GPIO3 | strapping | adc · pwm | |
| 4 | 4 | D3A3GPIO4 | safe | adc · pwm | |
| 5 | 5 | D4A4SDAGPIO5 | safe | adc · pwm · i2c | |
| 6 | 6 | D5A5SCLGPIO6 | safe | adc · pwm · i2c | |
| 7 | 43 | D6TXGPIO43 | strapping | uart · pwm | |
| 8 | - | 5V | power | - | 5V power input/output |
| 9 | - | GND | ground | - | |
| 10 | - | 3V3 | power | - | 3.3V power |
| 11 | 9 | D10A10MOSIGPIO9 | strapping | adc · pwm · spi | |
| 12 | 8 | D9A9MISOGPIO8 | safe | adc · pwm · spi | |
| 13 | 7 | D8A8SCKGPIO7 | safe | adc · pwm · spi | |
| 14 | 44 | D7RXGPIO44 | strapping | 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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| D2 | GPIO3 | Sampled at reset to select JTAG interface (USB Serial/JTAG controller vs. external pins). Improper use can disable external JTAG or alter debug interface. | Strapping |
| D6 | U0TXD (GPIO43) | Used for bootloader output and UART console logs. If repurposed, you will lose the default serial output (and programming via UART0). | Other |
| D7 | U0RXD (GPIO44) | Used for bootloader input (download mode via serial). If repurposed, you cannot use the default UART0 download mode for programming the chip. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| D10 | FSPIHD | Connected to external flash (data/hold signal) on most modules. Not recommended for use as GPIO, since it must remain dedicated to flash communication. | Flash |
Pinout notes 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…
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 and PWM on every GPIO.
3 of the exposed pins carry boot-time or system duties on the ESP32-S3 (D2, D6 and D7) - 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 · QIO
Upload Speed: 921600
// blink
pinMode(1, OUTPUT);
digitalWrite(1, LOW); // on (often inverted)[env:xiao-esp32s3]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32-s3-devkitc-1
variant: XIAO_ESP32S3
framework:
type: esp-idf
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32s3 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binGood to know
board-specific quirks worth 60 seconds
Specifications
ESP32-S3 · 21 × 17.8 mmAbout 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 $13.00 it's cheaper than most ESP32-S3 boards, which usually run around $30.
The small footprint costs pins: 11 GPIO are broken out, versus 21 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.
- Dual-core Xtensa LX7 processor with AI acceleration
- Supports WiFi 4 and Bluetooth 5 (LE)
- Ultra-small size (21x17.5 mm)
Where to buy
prices are typical street pricesResources
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