ESP32-C3 SuperMini is a tiny (22.5 × 18 mm) and very cheap board with the ESP32-C3 chip – a single-core RISC-V with Wi-Fi and Bluetooth LE.
It has no USB-serial converter: the USB-C connector goes directly to the chip (USB Serial/JTAG), which is used for both uploading and debugging.
Specifications
- ESP32-C3: RISC-V up to 160 MHz, 400 kB SRAM
- 4 MB flash inside the chip package
- Wi-Fi 4 (2.4 GHz) and Bluetooth 5 (LE), ceramic antenna
- 13 GPIO on the headers, 6 channels of 12-bit ADC (GPIO0–5)
- UART, I2C and SPI on any pin (GPIO matrix), PWM on all
- USB-C with native USB, blue LED on GPIO8, BOOT (GPIO9) and RESET buttons
The board is made by many manufacturers and individual units may differ in details. In the Arduino IDE, select Nologo ESP32C3 Super Mini (in the generic ESP32C3 Dev Module, LED_BUILTIN points to an RGB LED and the blue LED won’t blink) and enable USB CDC On Boot, otherwise you won’t see the Serial output.
Pinout and pin table
Hover over a pin in the diagram or a table row; use the filter to highlight a bus. You can download the pinout as PNG or SVG.
| Pin | Name | Direction | UART | I2C | SPI | ADC | Note |
|---|---|---|---|---|---|---|---|
| 1 | GPIO5 | input/output | MISO | ADC2_CH0 | ADC2 is not calibrated and does not work on some chip revisions – prefer ADC1. JTAG MTDI | ||
| 2 | GPIO6 | input/output | MOSI | JTAG MTCK | |||
| 3 | GPIO7 | input/output | SS | JTAG MTDO | |||
| 4 | GPIO8 | input/output | SDA | Strapping pin – must be logic 1 at boot for download mode. Blue LED | |||
| 5 | GPIO9 | input/output | SCL | BOOT button. Strapping pin – logic 0 at boot = download mode | |||
| 6 | GPIO10 | input/output | |||||
| 7 | GPIO20 | input/output | RX | UART0 RX | |||
| 8 | GPIO21 | input/output | TX | UART0 TX | |||
| 9 | GPIO0 | input/output | ADC1_CH0 | ||||
| 10 | GPIO1 | input/output | ADC1_CH1 | ||||
| 11 | GPIO2 | input/output | ADC1_CH2 | Strapping pin – should be logic 1 at boot (pull-up recommended) | |||
| 12 | GPIO3 | input/output | ADC1_CH3 | ||||
| 13 | GPIO4 | input/output | SCK | ADC1_CH4 | JTAG MTMS | ||
| 14 | 3V3 | output | 3.3 V output from the regulator | ||||
| 15 | GND | – | |||||
| 16 | 5V | input/output | 5 V from the USB connector. It can also power the board – ideally connect the supply through a diode so voltage does not flow back into USB. |
Pins used on the board
These chip pins are used by parts on the board and are not broken out:
| Pin | Function on the board |
|---|---|
| GPIO18 | USB D− (native USB Serial/JTAG) |
| GPIO19 | USB D+ |
What to watch out for
- The GPIO are not 5V tolerant. Use a level shifter for 5V signals.
- The LED on GPIO8 lights up at logic 0, and GPIO8 is also a strapping pin – it must be at logic 1 at boot.
- GPIO9 is the BOOT button: logic 0 at boot = download mode. GPIO2 is also a strapping pin – don’t pull it to logic 0 at boot.
- ADC2 (GPIO5) is not calibrated and does not work on some chip revisions – use GPIO0–4 for analog.
- Some cheap units have weak Wi-Fi (no clearance or ground around the antenna). Lowering the transmit power helps, e.g.
WiFi.setTxPower(WIFI_POWER_8_5dBm), or solder on a wire antenna. - If the board stops showing up on USB after uploading a program, hold BOOT, press RESET and release BOOT – it will start in download mode.
ESP32-C3 projects on chiptron.eu/
Projects and guides on chiptron.eu/:
- ESP32 Plane Radar – aircraft radar with an ESP32-C3 Super Mini and a round GC9A01 display
- Air quality monitoring – open-source project with SEN66, MemoryLCD and Home Assistant support
- A box full of sensors – air quality monitoring with the Meteo Mini board with ESP32-C3
- ESP32 chip comparison – which ESP32 to choose based on peripherals and project needs
More pinouts
See all pinouts on the Pinouts page.