ESP32-C3 Super Mini

The ESP32-C3 Super Mini is a widely available and very cheap (€1.50 at AliExpress) microcontroller board that is easy to use, has good support in many platforms, and provides ten freely usable GPIOs.

• Compact: extremely small board (22.5x18mm)
• Easy To Use: works out of the box with many environments like platform.io or ESPHome. There are no issues with entering firmware upload mode, and no fiddling with pressing buttons to select the right mode
• Ultra Low Power: comes with low power consumption and ultra low power modes and supports Bluetooth BLE, making it ideal for battery-operated devices
• Shields: battery shields are available that add battery charging and portable power supply to the C3 Super Mini
• Cheap: available for under €1.50 per piece

The board has a USB-C connector and ten freely usable GPIOs. Four GPIOs can also be used as analog input:

A programmable blue LED is connected to GPIO 8 (inverted: low active), and a red power LED is on when the board is connected to 5V (using its internal voltage regulator), else off (to conserve energy).

Limitations are:

• Performance: while its performance is more than sufficient for most DIY projects and much better than i.e. ESP8266, it uses a single core microcontroller at 160MHz clock speed. The classic ESP32s in comparison is a dual-core microcontroller running at 240MHz. If your project involves computing-intense tasks or needs to respond in real-time to more than one task, you may want to use a different microcontroller.
• GPIOs: due to its small form factor, the ESP32-C3 Super Mini only exposes 10 out of the available 22 GPIOs.

Performance

Key in your decision should be your performance requirements. Here is a comparison to give a good sense how the C3 compares:

GPIO

The ESP32-C3 has 22 GPIOs of which the C3 Super Mini exposes 13 due to its compact size. Of these 13 GPIO, 10 are freely usable whereas the remaining 3 GPIOs are strapping pins and cannot be used during the boot procedure.

All GPIOs are multifunctional and can be configured for various purposes, such as digital I/O, ADC (Analog-to-Digital Converter), UART, SPI, I2C, PWM, and more.

Ten Freely Usable GPIOs

These 10 GPIO can be freely used:

Additional Three GPIOs

If you require more GPIOs, then these three GPIOs can be used with certain restrictions:

JTAG is available on GPIO4-GPIO7.

Interfaces

Boot Modes

The strapping pins control the boot behavior during the boot process:

Board Schematics

Programmable LED

The board has a blue LED connected to GPIO8. This LED is inverted: low turns the LED on, and high turns it off.

Programming

The ESP32-C3 Super Mini is widely adopted and simple to use.

platformio

In platformio, use the board ESP32-C3-DevKitM-1.

[env:esp32-c3-devkitm-1]
platform = espressif32
board = esp32-c3-devkitm-1

Other IDs may work equally well:

[env:lolin_c3_mini]
platform = espressif32
board = seeed_xiao_esp32c3

ESPHome

In ESPHome configurations, use the board id esp32-c3-devkitm-1:

esp32:
  board: esp32-c3-devkitm-1

You can adjust and override specs if needed:

esphome:
  name: c3-supermini-test
  friendly_name: C3 SuperMini Test
  platformio_options:
    board_build.f_flash: 40000000L
    board_build.flash_mode: dio
    board_build.flash_size: 4MB

esp32:
  board: esp32-c3-devkitm-1
  variant: esp32c3
  framework:
    type: arduino

light:
  - platform: status_led
    name: "Status LED"
    id: esp_status_led
    icon: "mdi:alarm-light"
    pin:
      number: GPIO8
      inverted: true
    restore_mode: ALWAYS_OFF

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^{_{(content created Aug 28, 2024)}}