Seeed Studio XIAO ESP32C6 is a thumb-sized board (21 × 17.8 mm) with the ESP32-C6 chip: Wi-Fi 6, Bluetooth LE 5 and Zigbee/Thread. It has both a ceramic antenna and a U.FL connector, switchable from software, and a Li-Po cell charger.
The pin layout is the same across the entire XIAO series.
Specifications
- ESP32-C6FH4: RISC-V up to 160 MHz + 20 MHz low-power core, 512 kB SRAM, 4 MB flash
- Wi-Fi 6 (2.4 GHz), Bluetooth LE 5, Zigbee and Thread
- 11 GPIO on the headers (D0–D10), 3 of them analog inputs; more GPIO on pads on the bottom
- UART, I2C, SPI, PWM
- USB-C (native USB), Li-Po cell charging via the BAT pads
- ceramic antenna and U.FL connector with an RF switch (GPIO3, GPIO14)
- 21 × 17.8 mm, castellated pads on the edge
The antenna switch has to be enabled: GPIO3 at logic 0 powers it, GPIO14 selects the antenna (logic 0 ceramic, logic 1 external). Arduino does this automatically at boot; in ESPHome and ESP-IDF you have to set it yourself.
Pinout and pin table
Hover over a pin in the diagram or a table row; use the filter to highlight a bus. You can download the pinout as PNG or SVG.
Bottom side
| Pin | Name | Arduino | Direction | UART | I2C | SPI | ADC | Note |
|---|---|---|---|---|---|---|---|---|
| 1 | GPIO0 | D0/A0 | input/output | ADC1_CH0 | LP GPIO0 – can wake from deep sleep and be controlled by the low-power core. Same for GPIO1 and GPIO2 (D1, D2). | |||
| 2 | GPIO1 | D1/A1 | input/output | ADC1_CH1 | ||||
| 3 | GPIO2 | D2/A2 | input/output | ADC1_CH2 | ||||
| 4 | GPIO21 | D3 | input/output | SS | ||||
| 5 | GPIO22 | D4 | input/output | SDA | ||||
| 6 | GPIO23 | D5 | input/output | SCL | ||||
| 7 | GPIO16 | D6 | input/output | TX | UART0 TX (through a 499 Ω resistor on the board) | |||
| 8 | GPIO17 | D7 | input/output | RX | UART0 RX | |||
| 9 | GPIO19 | D8 | input/output | SCK | ||||
| 10 | GPIO20 | D9 | input/output | MISO | ||||
| 11 | GPIO18 | D10 | input/output | MOSI | ||||
| 12 | 3V3 | output | 3.3 V output from the converter | |||||
| 13 | GND | – | ||||||
| 14 | 5V | input/output | 5 V from the USB connector. It can also power the board – ideally connect the supply through a diode so voltage does not flow back into USB. No voltage here when running on battery. | |||||
| Bottom side | GPIO5 | input/output | ADC1_CH5 | Pad underneath. JTAG MTDI; strapping pin (SDIO slave timing) – normally no effect | ||||
| Bottom side | GPIO7 | input/output | Pad underneath. JTAG MTDO | |||||
| Bottom side | EN | input | Reset (button R) – connecting to GND restarts the chip | |||||
| Bottom side | GND | – | ||||||
| Bottom side | GPIO4 | input/output | ADC1_CH4 | Pad underneath. JTAG MTMS; strapping pin (SDIO slave timing) – normally no effect | ||||
| Bottom side | GPIO6 | input/output | ADC1_CH6 | Pad underneath. JTAG MTCK | ||||
| Bottom side | GPIO9 | input/output | Button B (BOOT), pad on the bottom. Strapping pin – logic 0 at boot = download mode | |||||
| Bottom side | 3V3 | output | 3.3 V output from the converter | |||||
| Bottom side | BAT+ | input/output | 3.7 V Li-Po cell positive – the board charges it from USB | |||||
| Bottom side | BAT- | – | Cell negative (GND) |
Pins used on the board
These chip pins are used by parts on the board and are not broken out:
| Pin | Function on the board |
|---|---|
| GPIO3 | Antenna switch power – logic 0 = on (Arduino enables it automatically) |
| GPIO14 | Antenna select – logic 0 onboard ceramic, logic 1 U.FL connector |
| GPIO15 | User LED (lit at logic 0) |
| GPIO8 | Strapping pin, not broken out (pull-up) |
| GPIO12 | USB D− |
| GPIO13 | USB D+ |
What to watch out for
- The GPIO are not 5V tolerant.
- Without the antenna switch enabled (GPIO3 at logic 0), Wi-Fi range is poor.
- The user LED (GPIO15) lights up at logic 0.
- Button B is GPIO9 (strapping pin – logic 0 at boot = download mode).
- Only connect a 3.7 V Li-Po/Li-Ion cell to the BAT pads.
XIAO ESP32C6 on chiptron.eu/
Projects and guides on chiptron.eu/:
- Pocket oscilloscope – the ESP-Scope web oscilloscope built on the XIAO ESP32C6
- MeshCore – LoRa network setup, XIAO boards are among the supported hardware
- ESP32 chip comparison – when to choose the C6 (Wi-Fi 6, Zigbee, Thread)
More pinouts
See all pinouts on the Pinouts page.