ESP32 C3 Super Mini

Board summary

ManufacturerWemos
Board docs (C3 mini)C3 Mini
Datasheet (C3 series)esp32_c3_datasheet.pdf1
Technical Reference Manualesp32-c3_technical_reference_manual_en.pdf
Dimensions (C3 mini)esp32_c3_mini_dimensions.pdf
Schematic (C3 mini)esp32_c3_schematic.pdf
Pinoutesp32_c3_supermini_pinout.jpg (topside), esp32_c3_supermini_pinout_under.jpg (underside)
MicrosoftESP32-C3 SuperMini
PlatformIOEspressif ESP32-C3-DevKitM-12
AnnouncementIntroducing ESP32-C3
ESPHome platformESP32 Platform3
Recomended frameworkesp-idf4
ESPHome configpackages/boards/esp32c3supermini.yaml5

 

ESP32 C3 Super Mini

ESP32 C3 Super mini

ESPHome support

Board config:

esphome:
  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: esp-idf

Config for status_led:

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

Pinout

ESP32 C3 Super Mini pinout (topside)

ESP32 C3 Super Mini pinout (underside)

Pins

The ESP32 C3 series has 2x ADCs, 6x PWM channels, 2x UART, 1x I²C and 3x SPI6.

InterfacePinsNotes
ADC1GPIO0-GPIO4
ADC2GPIO5Not usable when Wi-Fi is enabled6.
UARTAny GPIO pins
LED PWMAny GPIO pins6x PWM channels
I²CAny GPIO pins
SPI0NoneUsed by internal GDMA controller
SPI1NoneUsed by CPU
SPI2Any

Pin layout7:

Silkscreen pinInternal pinInterfaces
0GPIO0Analog, GPIO
1GPIO1Analog, GPIO
2GPIO2Analog, GPIO, boot
3GPIO3Analog, GPIO
4GPIO4Analog, GPIO, debug
5GPIO5GPIO, Debug
6GPIO6I²C SDA, GPIO, debug
7GPIO7I²C SCL, GPIO, debug
8GPIO8status_led (inverted), GPIO, boot
9GPIO9Boot button, boot mode, GBPIO
10GPIO10GPIO
20GPIO20UART RX, GPIO
21GPIO21UART TX, GPIO

Strapping pins:

GPIO pinDefaultControls
GPIO2FloatingBoot mode
GPIO8FloatingBoot mode, ROM message printing
GPIO9Pull-upBoot mode

Boot modes:

ModeGPIO2GPIO8GPIO9
SPI boot (default)HIGHAnyHIGH
UART/JTAG downloadHIGHHIGHLOW

Some notes on pins:

  • The blue status_led is on GPIO8 and is inverted.
  • The Wemos C3 Mini documentation shows a RGB led on GPIO7, but that might be on the C3 Mini only (and not SuperMini). This will be checked experimentally.

Enter bootloader mode to program over USB

If the ESP C3 SuperMini is unprogrammed, it seems to enter bootloader mode by default when plugged in with USB. If it has been programmed, it will connect and disconnected. To put the ESP32 C3 SuperMini into bootloader mode (if it is connecting/disconnected, or has been programmed):

  1. Plug in USB
  2. Hold both buttons
  3. Release both buttons at the same time

Before you press the buttons it will connect and disconnect.

Watching dmesg while you do this is helpful:

$ sudo dmesg -w

usb 3-2: Product: USB JTAG/serial debug unit
usb 3-2: Manufacturer: Espressif
cdc_acm 3-2:1.0: ttyACM0: USB ACM device

usb 3-2: USB disconnect, device number 89

On Linux (Fedora) it show up as /dev/ttyACM0 (or ttyACM1 etc).