No Matches
Wemos ESP32-C3 mini

Support for generic ESP32-C3 boards. More...

Detailed Description

Support for generic ESP32-C3 boards.

Gunar Schorcht gunar.nosp@m.@sch.nosp@m.orcht.nosp@m..net

Wemos ESP32-C3 mini

Table of Contents

  1. Overview
  2. Hardware
    1. MCU
    2. Board Configuration
    3. Board Pinout
  3. Flashing the Device


The Wemos ESP32-C3 mini board is an interesting development kit as it uses in the stackable Wemos LOLIN D1 Mini format. Thus, all shields for Wemos D1 mini for ESP8266 can also be used with ESP32-C3. Examples for such shields are:

This makes it possible to create different hardware configurations without the need for a soldering iron or a breadboard.

Wemos ESP32-C3 mini board

This stackable platform was tested in an RIOT application with:

This application is a good example how easy it is with this board to create different hardware applications.

RIOT application with MRF24J40 Radio and a BMP180 Pressure Sensor

Back to table of contents


This section describes

Back to table of contents


Most features of the board are provided by the ESP32-C3 SoC. For detailed information about the ESP32-C3 variant (family) and ESP32x SoCs, see section ESP32 SoC Series.

Back to table of contents

Board Configuration

The Wemos ESP32-C3 mini board has no special hardware on board with the exception of a single pin RGB-LED.

There are two board versions available on the market with a different pinout of the ADC channels and the SPI interface. Which version is used is determined by activating a pseudo module for the corresponding version:

To specify which board version is used, simply add the variable definition USEMODULE=... to the make command line, for example:

USEMODULE=esp32c3_wemos_mini_v1_0_0 BOARD=esp32c3-wemos-min make ...

If the board version is not specified, version v2.1.0 is used by default.

Almost all GPIOs are broken out and can be used for different peripherals:

However, since the number of GPIOs of the ESP32-C3 SoC is very limited, some GPIOs are used in multiple peripheral configurations but can only be used for one peripheral at a time. For example, GPIO4 is used in the ADC channel configuration and in the MOSI signal configuration for SPI_DEV(0). This is possible because GPIOs are only used for a specific peripheral interface when either

That is, the purpose for which a GPIO is used depends on which module or function is used first. For example, if module periph_spi is not used, the GPIOs listed in SPI configuration can be used for other purposes, that is, GPIO4 can be used as ADC channel.

The following table shows the default board configuration depending on used board version, which is sorted according to the defined functionality of GPIOs. This configuration can be overridden by application-specific configurations.

Function v1.0.0 v2.1.0 Remarks Configuration
ADC GPIO0 ... GPIO5 GPIO0 ... GPIO5 see ADC Channels
I2C_DEV(0):SCL GPIO10 GPIO10 I2C Interfaces
I2C_DEV(0):SDA GPIO8 GPIO8 I2C Interfaces
RGB-LED - GPIO7 supported by driver module ws281x
SPI_DEV(0):CLK GPIO2 GPIO1 SPI2_HOST (FSPI) is used SPI Interfaces
SPI_DEV(0):MISO GPIO3 GPIO0 SPI2_HOST (FSPI) is used SPI Interfaces
SPI_DEV(0):MOSI GPIO4 GPIO4 SPI2_HOST (FSPI) is used SPI Interfaces
SPI_DEV(0):CS0 GPIO5 GPIO5 SPI2_HOST (FSPI) is used SPI Interfaces
UART_DEV(0):TxD GPIO21 GPIO21 Console (configuration is fixed) UART interfaces
UART_DEV(0):RxD GPIO20 GPIO20 Console (configuration is fixed) UART interfaces

The configuration of ADC channels contains all ESP32-C3 GPIOs that could be used as ADC channels.

For detailed information about the peripheral configurations of ESP32-C3 boards, see section Common Peripherals.

Back to table of contents

Board Pinout

The following figures show the pinouts as configured by default board definition.

Wemos EPS32-C3 mini Pinout

The corresponding board schematics can be found:

Back to table of contents

Flashing the Device

The USB-C connector of the board is directly connected to the USB Serial/JTAG interface of the ESP32-C3 SoC. It can be used to program the board and to debug the application. Just connect the board to your host computer and use the following command:

make flash BOARD=esp32c3-devkit ...

The make system will resets the board to restart the board into download mode. In some special cases this reset does not work so that the programmer cannot connect to the board and the flashing is aborted with a timeout:

Serial port /dev/ttyACM0
serial.serialutil.SerialTimeoutException: Write timeout
static SerialPort Serial(ARDUINO_UART_DEV)
Primary serial port (mapped to ARDUINO_UART_DEV)

In this case, restart the board manually in download mode by pressing and releasing the RESET button while holding down the BOOT button.

After flashing the board, it will still be in download mode. You have to press the reset button (RST) to start your application.

For detailed information about ESP32-C3 as well as configuring and compiling RIOT for ESP32-C3 boards, see RIOT-OS on ESP32 SoC Series Boards.

Back to table of contents


file  arduino_iomap.h
 Mapping from MCU pins to Arduino pins.
file  board.h
 Board definitions for the Wemos ESP32-C3 mini board.
file  gpio_params.h
 Board specific configuration of direct mapped GPIOs.
file  periph_conf.h
 Peripheral configurations for the Wemos ESP32-C3 mini board.