Another board – the ESP32C3-CORE Development Board

This is another ESP32 I purchased for the collection

CORE ESP32 core board is a core board designed based on Espressif ESP32-C3, the size is only 21mm*51mm, and the edge of the board is designed with stamp holes, which is convenient for developers to use in different scenarios. 
The core board supports UART, GPIO, SPI, I2C, ADC, PWM and other interfaces, which can be selected according to actual needs.
Here is a picture of the board, it is marked with a website on the back


    • Size length and width 21mm*51mm
    • 1 way SPI FLASH, onboard 4MB, support up to 16MB
    • 2-way UART interface, UART0~UART1, among which the download port is UART0
    • 5 channels of 12-bit ADC, the highest sampling rate is 100KSPS
    • 1 low-speed SPI interface, support master mode
    • 1 way IIC controller
    • 4-way PWM interface, any GPIO can be used
    • 15 GPIO external pins, reusable
    • 2-way SMD LED indicator light
    • 1 way reset button + 1 way BOOT button
    • 1 USB to TTL download and debug port
    • 2.4G PCB onboard antenna


Now lets look at the pinout and functions of the board

Pin Number Name Default function multiplexing function
32 GND grounding
31 5V 5V power interface, connected to VBUS of USB
29 IO08 GPIO08, input, output, high impedance
28 IO04 GPIO04, input, output, high impedance I2C_SDA/ADC_4
27 IO05 GPIO05, input, output, high impedance I2C_SCL/ADC_5
26 3.3V Chip power supply, 3.3V
25 GND ground
24 PB_11 GPIO11, input, output, high impedance VDD_SPI
23 IO07 GPIO07, input, output, high impedance SPI2_CS
22 IO06 GPIO06, input, output, high impedance
21 IO10 GPIO10, input, output, high impedance SPI2_MISO
20 IO03 GPIO03, input, output, high impedance SPI2_MOSI/ADC_3
19 IO02 GPIO02, input, output, high impedance SPI2_CK/ADC_2
18 3.3V Chip power supply, 3.3V
17 GND ground
16 5V 5V power interface, connected to VBUS of USB
15 PWB Chip 3.3V power supply control, high level is effective, can be suspended when not in use
14 GND ground
13 3.3V Chip power supply, 3.3V
12 RESET chip reset
11 NC
10 IO13 GPIO13, input, output, high impedance
09 U0_RX GPIO20, input, output, high impedance UART0_RX
08 U0_TX GPIO21, input, output, high impedance UART0_TX
07 GND ground
06 IO19 GPIO19, input, output, high impedance USB_D+
05 IO18 GPIO18, input, output, high impedance USB_D-
04 IO12 GPIO12, input, output, high impedance SPIHD
03 IO01 GPIO1, input, output, high impedance UART1_RX/ADC_1
02 IO00 GPIO0, input, output, high impedance UART1_TX/ADC_0
01 GND ground


The ESP32 core board has 2 LEDs on board that can be used.

LED GPIO pin description
D4 IO12 GPIO12 configuration
D5 IO13 GPIO13 configuration


There are two buttons on the ESP32 core board, among which the BOOT button can perform the BOOT download function, and the RST button can be used for the reset function, 

Button pin description
BOOT/GPIO9 When the button is pressed, the chip enters the download mode
RST When the button is pressed, the chip resets


The CORE ESP32 core board equipped with ESP32-C3 is a version without built-in FLASH, and the external SPI FLASH is mounted by default.

If you encounter a core without external SPI FLASH, you need to pay attention to the specific model of the main chip. Using built-in Flash is GPIO11/12/13not available.

flash pin pin description
SPICS0 GPIO14 configuration, FLASH_CS, chip select
SPIQ GPIO17 configuration, FLASH_D1, data pin 1
SPID GPIO16 configuration, FLASH_D0, data pin 0
SPICLK GPIO15 configuration, FLASH_CK, clock


This board seems to be designed to work with a development environment called LuatIDE and LuatOS, so I will check these out but being an ESP32-C£ it will work with Arduino IDE and Micropython


Hardware Information

Schematic of CORE-ESP32-C3 development board

New version of CORE-ESP32-C3 development board schematic diagram (version without serial port chip)