xiao - SKILL.md Agent Skill

name: xiao description: Pin definitions and board specifications for SeeedStudio XIAO series microcontrollers. Use this skill to identify correct GPIO pins, alternate functions, power domains, strapping pins, or boot mode restrictions for XIAO boards (ESP32C3/C5/C6/S3, nRF52840, RP2040/RP2350, SAMD21, MG24, nRF54L15, RA4M1). Provides board selection guidance and links to platform sub-skills. Requires a platform sub-skill for code implementation.

XIAO Board Reference

This skill provides pin definitions and board specifications for SeeedStudio XIAO series. For code implementation, use the appropriate platform sub-skill.

Platform Sub-Skills

Platform	Sub-Skill	When to Use
Arduino	`/xiao-arduino`	Arduino/C++ framework development
MicroPython	`/xiao-micropython`	MicroPython development
ESPHome	`/xiao-esphome`	Home Assistant ESPHome YAML configs

First select your platform sub-skill, then read board reference below.

Board Selection

Read the corresponding board reference for pin definitions:

Board	Reference	Platform Support
ESP32C3	`boards/esp32c3.md`	Arduino, MicroPython, ESPHome
ESP32C5	`boards/esp32c5.md`	Arduino
ESP32C6	`boards/esp32c6.md`	Arduino, MicroPython, ESPHome
ESP32S3	`boards/esp32s3.md`	Arduino, MicroPython, ESPHome
ESP32S3 Sense	`boards/esp32s3.md`	Arduino, MicroPython
nRF52840	`boards/nrf52840.md`	Arduino, MicroPython
nRF52840 Sense	`boards/nrf52840.md`	Arduino, MicroPython
RP2040	`boards/rp2040.md`	Arduino, MicroPython, ESPHome
RP2350	`boards/rp2350.md`	Arduino
SAMD21	`boards/samd21.md`	Arduino
MG24	`boards/mg24.md`	Arduino
MG24 Sense	`boards/mg24.md`	Arduino
nRF54L15 Sense	`boards/nrf54l15.md`	MicroPython only
RA4M1	`boards/ra4m1.md`	Arduino

Board Quick Reference

ESP32 Series

Board	Wireless	GPIO	ADC	Special
ESP32C3	WiFi, BLE	11	5	Low cost
ESP32C5	WiFi, BLE	~11	-	WiFi 6
ESP32C6	WiFi, BLE	13	5	Zigbee, low power
ESP32S3	WiFi, BLE	11	4	Dual-core, AI

nRF Series

Board	Wireless	GPIO	ADC	Special
nRF52840	BLE 5.0	21	6	NFC, USB
nRF52840 Sense	BLE 5.0	21	6	+ PDM mic
nRF54L15 Sense	BLE 5.4	15	4	Ultra low power

RP Series

Board	GPIO	ADC	Special
RP2040	30	4	PIO, SWD boot
RP2350	30	4	ARM M33, DSP

Other

Board	GPIO	ADC	Special
SAMD21	16	6	USB HID
MG24	20	8	Matter, Zigbee
RA4M1	18	14	Arduino UNO R4 chip

Expansion Boards

XIAO expansion boards add peripherals and capabilities. For complete hardware documentation, see references/expansion_boards/.

Expansion Board	Key Features	Arduino Reference
Expansion Base	OLED, RTC, SD card, buzzer, Grove connectors	`xiao-arduino:expansion-boards/expansion-base.md`
Round Display	1.28" touchscreen (240x240)	`xiao-arduino:expansion-boards/round-display.md`
Grove Shield	8 Grove connectors + battery management	`xiao-arduino:expansion-boards/grove-shield.md`
ePaper V2	7 ePaper display sizes (1.54" to 7.5")	`xiao-arduino:expansion-boards/epaper-v2.md`
CAN Bus	MCP2515 controller for automotive/industrial	`xiao-arduino:expansion-boards/can-bus.md`
RS485	Industrial communication	`xiao-arduino:expansion-boards/rs485.md`
LED Driver	5V/12V LED strips with WLED support	`xiao-arduino:expansion-boards/led-driver.md`
Bus Servo	Serial bus servo control for robotics	`xiao-arduino:expansion-boards/bus-servo.md`
GPS/GNSS	L76K GNSS module for positioning	`xiao-arduino:expansion-boards/gps-gnss.md`
GPIO Expander	MCP23017 16-bit I/O expansion	`xiao-arduino:expansion-boards/gpio-expander.md`
RGB Matrix	RGB LED matrix driver	`xiao-arduino:expansion-boards/rgb-matrix.md`
COB LED	Chip-on-Board LED lighting	`xiao-arduino:expansion-boards/cob-led.md`

For detailed hardware specifications, pin mappings, and compatibility, see references/expansion_boards/.

Critical Pin Restrictions

ESP32 Series Strapping Pins

These pins affect boot mode - avoid using or use carefully:

Board	Pin	Function	Restriction
ESP32C3/C6	D8 (GPIO20/8)	SPI SCK	Must be HIGH/float at boot
ESP32C3/C6	D9 (GPIO21/9)	SPI MISO	Connected to BOOT button
ESP32C3/C6	D0, D1	USB D-/D+	Used for USB upload
ESP32S3	D0, D1	GPIO16/17	USB D-/D+
ESP32S3	D8, D9	GPIO8/9	Strapping pins

Warning: Using strapping pins incorrectly can prevent booting or uploading.

RP2040 BOOTSEL

Hold BOOTSEL button while connecting USB to enter firmware upload mode
Drive appears as RPI-RP2 mass storage

I2C/SPI/UART Pin Mappings

Pin mappings vary by board - always check board reference before wiring.

Sense Models

For camera/microphone sensor boards, see special/sense-models.md:

ESP32S3 Sense camera configuration
nRF52840 Sense PDM microphone
MG24 Sense built-in sensors

Low Power

Deep sleep and power optimization are platform-specific. Use your platform sub-skill:

Arduino: Use the /xiao-arduino skill and see the API documentation for deep sleep (ESP32, nRF52, RP2040)
MicroPython: Use the /xiao-micropython skill and see the API documentation for deep sleep (ESP32, nRF52, RP2040)
ESPHome: Use the /xiao-esphome skill and see the advanced documentation for deep sleep configuration

Bootloader Reflash

For bootloader recovery or firmware flashing procedures, see special/bootloader-reflash.md.

Reference Structure

xiao/
├── boards/              # Pin definitions for each board (READ THIS FIRST)
├── expansion_boards/    # XIAO expansion board hardware documentation
│   ├── README.md        # Expansion board overview and selection guide
│   ├── expansion-base.md
│   ├── round-display.md
│   ├── grove-shield.md
│   ├── epaper-v2.md
│   ├── can-bus.md
│   ├── rs485.md
│   ├── led-driver.md
│   ├── bus-servo.md
│   ├── gps-gnss.md
│   ├── gpio-expander.md
│   ├── rgb-matrix.md
│   └── cob-led.md
└── special/
    ├── bootloader-reflash.md  # Bootloader recovery
    └── sense-models.md        # Sense model camera/sensors

Workflow

Load platform sub-skill first (/xiao-arduino, /xiao-micropython, /xiao-esphome)
Read board reference for pin definitions (e.g., boards/esp32c3.md, boards/rp2040.md)
Check pin restrictions for strapping/boot pins
Generate code using platform sub-skill patterns

Important Notes

Always verify pin mappings in board reference before connecting peripherals
Avoid strapping pins on ESP32 boards unless necessary
Use appropriate sub-skill for code examples and platform patterns
Check Sense model docs for camera/microphone configuration