XIAO ESP32C3

Overview

Seeed Studio XIAO ESP32C3 is an IoT mini development board based on the Espressif ESP32-C3 WiFi/Bluetooth dual-mode chip.

For more details see the Seeed Studio XIAO ESP32C3 [1] wiki page.

Hardware

This board is based on the ESP32-C3 with 4MB of flash, WiFi and BLE support. It has an USB-C port for programming and debugging, integrated battery charging and an U.FL external antenna connector. It is based on a standard XIAO 14 pin pinout.

Supported Features

The xiao_esp32c3 board supports the hardware features listed below.

on-chip / on-board
Feature integrated in the SoC / present on the board.
2 / 2
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

xiao_esp32c3/esp32c3 target

Type

Location

Description

Compatible

CPU

on-chip

Espressif RISC-V CPU1

espressif,riscv

ADC

on-chip

ESP32 ADC1

espressif,esp32-adc

Bluetooth

on-chip

Bluetooth HCI for Espressif ESP321

espressif,esp32-bt-hci

CAN

on-chip

ESP32 Two-Wire Automotive Interface (TWAI)1

espressif,esp32-twai

Clock control

on-chip

ESP32 RTC (Power & Clock Controller Module) Module1

espressif,esp32-rtc

Counter

on-chip

ESP32 Counter Driver based on RTC Main Timer1

espressif,esp32-rtc-timer

on-chip

ESP32 general-purpose timers2

espressif,esp32-timer

DMA

on-chip

ESP32 GDMA (General Direct Memory Access)1

espressif,esp32-gdma

Flash controller

on-chip

ESP32 flash controller1

espressif,esp32-flash-controller

GPIO & Headers

on-chip

ESP32 GPIO controller1

espressif,esp32-gpio

on-board

GPIO pins exposed on Seeeduino Xiao (and compatible devices) headers1

seeed,xiao-gpio

I2C

on-chip

ESP32 I2C1

espressif,esp32-i2c

I2S

on-chip

ESP32 I2S1

espressif,esp32-i2s

Interrupt controller

on-chip

ESP32 Interrupt controller1

espressif,esp32-intc

MTD

on-chip

Flash node1

soc-nv-flash

on-chip

Fixed partitions of a flash (or other non-volatile storage) memory1

fixed-partitions

Pin control

on-chip

ESP32 pin controller1

espressif,esp32-pinctrl

PWM

on-chip

ESP32 LED Control (LEDC)1

espressif,esp32-ledc

RNG

on-chip

ESP32 TRNG (True Random Number Generator)1

espressif,esp32-trng

Sensors

on-chip

ESP32 temperature sensor1

espressif,esp32-temp

Serial controller

on-chip

ESP32 UART1 1

espressif,esp32-uart

on-chip

ESP32 UART1

espressif,esp32-usb-serial

SPI

on-chip

ESP32 SPI1

espressif,esp32-spi

Timer

on-chip

ESP32 System Timer1

espressif,esp32-systimer

Watchdog

on-chip

ESP32 XT Watchdog Timer1

espressif,esp32-xt-wdt

on-chip

ESP32 watchdog1 1

espressif,esp32-watchdog

Wi-Fi

on-chip

ESP32 SoC Wi-Fi1

espressif,esp32-wifi

Connections and IOs

The board uses a standard XIAO pinout, the default pin mapping is the following:

XIAO ESP32C3 Pinout

XIAO ESP32C3 Pinout

Prerequisites

Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command below to retrieve those files.

west blobs fetch hal_espressif

Note

It is recommended running the command above after west update.

Building & Flashing

Simple boot

The board could be loaded using the single binary image, without 2nd stage bootloader. It is the default option when building the application without additional configuration.

Note

Simple boot does not provide any security features nor OTA updates.

MCUboot bootloader

User may choose to use MCUboot bootloader instead. In that case the bootloader must be built (and flashed) at least once.

There are two options to be used when building an application:

  1. Sysbuild

  2. Manual build

Note

User can select the MCUboot bootloader by adding the following line to the board default configuration file.

CONFIG_BOOTLOADER_MCUBOOT=y

Sysbuild

The sysbuild makes possible to build and flash all necessary images needed to bootstrap the board with the ESP32 SoC.

To build the sample application using sysbuild use the command:

west build -b xiao_esp32c3 --sysbuild samples/hello_world

By default, the ESP32 sysbuild creates bootloader (MCUboot) and application images. But it can be configured to create other kind of images.

Build directory structure created by Sysbuild is different from traditional Zephyr build. Output is structured by the domain subdirectories:

build/
├── hello_world
│   └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
├── mcuboot
│    └── zephyr
│       ├── zephyr.elf
│       └── zephyr.bin
└── domains.yaml

Note

With --sysbuild option the bootloader will be re-build and re-flash every time the pristine build is used.

For more information about the system build please read the Sysbuild (System build) documentation.

Manual build

During the development cycle, it is intended to build & flash as quickly possible. For that reason, images can be built one at a time using traditional build.

The instructions following are relevant for both manual build and sysbuild. The only difference is the structure of the build directory.

Note

Remember that bootloader (MCUboot) needs to be flash at least once.

For the Hello, world! application, follow the instructions below.

# From the root of the zephyr repository
west build -b xiao_esp32c3 samples/hello_world
west flash

Since the Zephyr console is by default on the usb_serial device, we use the espressif monitor to view.

$ west espressif monitor

After the board has automatically reset and booted, you should see the following message in the monitor:

***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
Hello World! xiao_esp32c3

Debugging

As with much custom hardware, the ESP32 modules require patches to OpenOCD that are not upstreamed yet. Espressif maintains their own fork of the project. The custom OpenOCD can be obtained at OpenOCD ESP32 [2].

The Zephyr SDK uses a bundled version of OpenOCD by default. You can overwrite that behavior by adding the -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts> parameter when building.

Here is an example for building the Hello World application.

# From the root of the zephyr repository
west build -b xiao_esp32c3 samples/hello_world -- -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>
west flash

You can debug an application in the usual way. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b xiao_esp32c3 samples/hello_world
west debug

References