The Seeed XIAO ESP32-C6

The ESP32-C6 on a thumbnail: 21 by 17.5 mm, fourteen pads, USB-C, and a yellow LED that lights on LOW.

What it is

The same RISC-V chip as the ESP32-C6-DevKitC-1, at 160 MHz, on the XIAO family's outline: seven castellated pads down each long edge, 0.6 inch apart, so it pushes into a breadboard across the channel. The USB goes to the chip's own USB port, and that is what Serial and the serial monitor use.

The pin numbers are the XIAO's

The silkscreen numbers are the XIAO family's, not the chip's, and sketches for this board use them: D0 to D10 and A0 to A2 are defined for you. They sit on the same pads as on the XIAO ESP32-C3, with other GPIOs under them.

Pad	GPIO	Also
D0	0	A0
D1	1	A1
D2	2	A2
D3	21
D4	22	I2C SDA
D5	23	I2C SCL
D6	16	UART TX
D7	17	UART RX
D8	19	SPI SCK
D9	20	SPI MISO
D10	18	SPI MOSI

A0 to A2 are ADC1 channels 0 to 2 and read the voltage on the net, against 3.3 V at full scale.

The user LED

The yellow LED is on GPIO 15, which no pad reaches, and it is wired from 3.3 V to the pin, so it lights when the pin is LOW. LED_BUILTIN is 15, and digitalWrite(LED_BUILTIN, LOW) turns it on. The built-in Blink does exactly that.

The BOOT and RESET buttons are buttons, not pads. BOOT grounds GPIO 9. There is no reset pad; the board's RESET button holds the chip in reset while it is pressed.

WiFi

It joins Mokxi's simulated network, with the network name and password as properties of the board. There is no radio, no 802.11 and no real internet: Simulated WiFi says what is faithful and what is not. The one exception is the Real internet switch in the Cloud panel, which sends requests for other names out through Mokxi's gateway. The antenna socket is drawn and does nothing.

What is modeled

The DevKitC-1 model's chip, whole: the RISC-V core, GPIO, UART0, the timers, ADC1 and LEDC PWM on any pin. Programs built for this board run on the DevKitC-1 and the other way around; the two carry different program strings so each is offered its own examples.

What is not modeled

The RF switch on GPIO 3 and 14 and the antenna it chooses, the battery charger and its pads on the back, the USB stack (Serial reaches the monitor directly), Thread, Zigbee and a real radio. Bluetooth LE is simulated: a phone in the editor's Bluetooth pane, not a real radio.

Starter project

XIAO C6 knob is the board across a breadboard with a potentiometer on A0 dimming an LED on D10, and the reading printed in millivolts: the XIAO ESP32-C3's circuit, pad for pad.