Reference

NodeMCU-ESP32-C2 Pinout

The pin reference for the NodeMCU-style ESP32-C2 development board: the ESP8684-WROOM-02 module, its exposed GPIOs, and how to flash it over USB-C.

21 september 2026 2 min read

The NodeMCU-ESP32-C2 is a NodeMCU-style development board built around Espressif’s ESP8684-WROOM-02 module, a different, larger module than the bare ESPC2-02 module this site already documents. Same ESP32-C2 chip underneath, more pins broken out and a full USB-C/CH340C programming circuit on board. This guide covers this specific development board: its GPIO layout, communication pins, and how to flash it.

System-on-chip and module

At the heart of this board is the ESP32-C2, marketed name for the ESP8684 chip: a single-core RISC-V SoC from Espressif with integrated 2.4GHz Wi-Fi, a secure bootloader and hardware encryption, built for low-cost, low-resource applications.

The board carries the ESP8684-WROOM-02 module: the chip, 2MB of SPI flash, a PCB antenna and the surrounding passives in one shielded package.

The development board itself breaks the module’s pins out to a breadboard-friendly, clearly labeled NodeMCU-style header, adds a CH340C USB-to-serial chip, and uses USB-C instead of micro-USB.

Key features

Wi-Fi 802.11 b/g/n (2.4GHz)
12-bit ADC on 5 of the exposed pins
UART, SPI, I²C and PWM, all software-assignable
USB-to-serial via onboard CH340C, no separate programmer needed
USB-C connector
2MB flash, embedded in the module

This is a smaller, cheaper board than the ESP32-S3/-C3/-C6 family: fine for simple sensors, wireless switches and other low-power, low-complexity connected devices, not for anything CPU- or memory-heavy.

GPIO quick reference

GPIO	Function	ADC	PWM	Notes
0	—	No	Yes	General purpose
1	ADC1_CH0	Yes	Yes	Analog input
2	ADC1_CH1, SPI MOSI	Yes	Yes
3	ADC1_CH2, SPI MISO	Yes	Yes
4	ADC1_CH3, SPI SCLK	Yes	Yes
5	ADC1_CH4	Yes	Yes	Analog input
6	I²C SDA	No	Yes	Default I²C pin, remappable
7	I²C SCL	No	Yes	Default I²C pin, remappable
9	BOOT strap	No	—	Hold low at reset to enter flash mode
10	SPI CS	No	Yes
20	UART0 TX	No	Yes	To CH340C, to your PC
21	UART0 RX	No	Yes	From CH340C, from your PC

All GPIOs are bidirectional digital I/O and support PWM. Remap I²C in Arduino with Wire.begin(SDA, SCL).

Flashing

Thanks to the onboard CH340C, flashing is plug-and-play over USB-C, no external USB-to-serial adapter needed.

Connect the board via USB-C.
In Arduino IDE or PlatformIO, select a generic ESP32C2 Dev Module board.
Click Upload.
If flashing fails to start automatically, hold IO9 (BOOT) low, tap EN/RESET, release IO9, then retry.

Do not hold IO9 low outside of flashing, it forces the board back into the bootloader instead of running your program.

Conclusion

The NodeMCU-ESP32-C2 trades GPIO count and processing power for cost and simplicity. If a project genuinely only needs Wi-Fi plus a handful of digital/analog pins, this is a cheaper, lower-power alternative to reaching for an ESP-WROOM-32D or ESP32-C3 board. For anything needing more GPIOs, Bluetooth, or more RAM, look at this site’s other ESP32 boards instead.