ESP Modules

ESP32-C3-WROOM-02

WROOM module · based on ESP32-C3 · Active

  • RISC-V
  • 1× @ 160 MHz
  • Wi-Fi 4
  • BLE 5.x
  • 4 / 8 / 16 MB flash
  • 15 GPIO
  • PCB antenna
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Figures here are compiled from Espressif's official datasheets, with the source linked on each page. Mistakes are possible, so if something looks off, please report it.

The ESP32-C3-WROOM-02 is a general-purpose Espressif module built on the ESP32-C3 single-core RISC-V SoC clocked up to 160 MHz. It pairs 2.4 GHz Wi-Fi 4 and Bluetooth LE with up to 16 MB flash, routes the radio to a PCB antenna, and breaks out 15 GPIO; the module measures 18 × 20 × 3.2 mm.

It's a balanced Wi-Fi + Bluetooth LE module suitable for a wide range of connected products. Secure boot and flash encryption are available for production security. Espressif lists target uses including Smart Home, POS Machines, Industrial Automation, Service Robot and Health Care.

Pinout

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Colour-coded by function · ✓ safe · ! use with care · – reserved (flash/USB). Generated from the datasheet, not an official Espressif figure.
ESP32-C3-WROOM-02 pinout diagram, pins colour-coded by function with safe and use-with-care badges
#NameTypeFunctions
13V3P Power supply ⚑
2ENI Chip enable ⚑
3IO4I/O/T GPIO4, ADC1_CH4, FSPIHD, MTMS ⚑
4IO5I/O/T GPIO5, ADC2_CH0, FSPIWP, MTDI ⚑
5IO6I/O/T GPIO6, FSPICLK, MTCK ⚑
6IO7I/O/T GPIO7, FSPID, MTDO ⚑
7IO8I/O/T GPIO8 ⚑
8IO9I/O/T GPIO9 ⚑
9,19GNDP Ground ⚑
10IO10I/O/T GPIO10, FSPICS0 ⚑
11RXDI/O/T GPIO20, U0RXD ⚑
12TXDI/O/T GPIO21, U0TXD ⚑
13IO18I/O/T GPIO18, USB_D- ⚑
14IO19I/O/T GPIO19, USB_D+ ⚑
15IO3I/O/T GPIO3, ADC1_CH3 ⚑
16IO2I/O/T GPIO2, ADC1_CH2, FSPIQ ⚑
17IO1I/O/T GPIO1, ADC1_CH1, XTAL_32K_N ⚑
18IO0I/O/T GPIO0, ADC1_CH0, XTAL_32K_P ⚑
Official datasheet pin-layout figure
ESP32-C3-WROOM-02 datasheet pin layout (top view)

Find a pin by function

Pick a capability to see which GPIOs provide it on the ESP32-C3.

Freely usable, no special role.

GPIO0general-purpose
GPIO1general-purpose
GPIO3general-purpose
GPIO10general-purpose

! Usable for general IO, but one function has a condition (e.g. ADC2 can't be read while Wi-Fi is on). See the note.

UART, I²C, SPI (master), I²S, PWM/LEDC and most digital peripherals route through the GPIO matrix, so assign them to any pin from "Safe GPIO". The categories above are the pins tied to a fixed function (analog, USB, crystal…) or that need care.

Strapping pins

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GPIOs sampled at reset; avoid driving these at power-up.

PinDefaultBitFunction
GPIO2floating—boot
GPIO8floating—rom_log
GPIO9pull-up1boot_mode

GPIO pin warnings

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On the ESP32-C3, almost any peripheral can be routed to almost any GPIO through the IO MUX, so most pins are free to use. These are the exceptions: pins with a fixed role or a boot-time behaviour to design around.

PinWhy it needs care
GPIO2strapping pin (affects boot)
GPIO4JTAG
GPIO5JTAG
GPIO6JTAG
GPIO7JTAG
GPIO8strapping pin (affects boot)
GPIO9strapping pin (affects boot)
GPIO18native USB D±
GPIO19native USB D±
GPIO20UART0 console (boot log)
GPIO21UART0 console (boot log)
  • The ADC2 channels share hardware with the Wi-Fi radio, so ADC2 readings are unavailable while Wi-Fi is active. Those GPIOs are still free for any digital function, and the ADC1 channels work for analog input alongside Wi-Fi.

Compute & memory

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CPURISC-V, 1-core
Max clock160 MHz
SRAM400 KB
ROM384 KB
Flash options4 / 8 / 16 MB
PSRAMNone
Co-processornone

Wireless

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Wi-FiWi-Fi 4
Wi-Fi bands2.4GHz
BluetoothBLE 5.x
802.15.4 (Thread/Zigbee)No
AntennaPCB

Peripherals & I/O

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Usable GPIO15
ADC6× 12-bit
USBUSB-Serial-JTAG
UART / SPI / I²C / I²S2 / 1 / 1 / 1
TWAI (CAN)Yes
SD/MMCNo
Ethernet MACNo
Touch0

Power

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Operating voltage3.0-3.6 V
Deep sleep5 µA

Physical

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Dimensions18 × 20 × 3.2 mm
Pin count19
Temp range-40 to 85 °C
MountingSMD castellated
LifecycleActive

Security

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Secure bootYes
Flash encryptionYes
CryptoAES, SHA, RSA, HMAC, RNG
Digital signatureYes
TRNGYes

Ordering codes

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The orderable part numbers and what each ships with, decoded from the suffix. Confirm against the latest datasheet before ordering.

Part numberFlashPSRAMTemp
ESP32-C3-WROOM-02-N4 4 MB — −40 to 85 °C

Schematics

ESP32-C3-WROOM-02 module reference-design schematic
Module reference design
ESP32-C3-WROOM-02 peripheral / application schematic showing how to wire the module
Peripheral / application circuit: how to wire it up

Mechanical & CAD

ESP32-C3-WROOM-02 physical dimensions drawing
Physical dimensions
ESP32-C3-WROOM-02 recommended PCB land pattern
Recommended PCB land pattern

Getting started

Frameworks: Arduino-ESP32 core (fully supported) · ESP-IDF 4.3+ (Espressif's official SDK) · MicroPython · Matter.

ESP-IDF target: idf.py set-target esp32c3.

The SoC has a built-in USB Serial/JTAG controller, so you can flash and debug over its native USB port with no external adapter.

Software & firmware

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Popular firmware and SDKs that run on the ESP32-C3, so they run on the ESP32-C3-WROOM-02 too.

Notable open-source software & firmware known to run on this chip. Support evolves, so check each project for its current board support.

Smart home & IoT

  • Tasmota★ 24k

    Mature open firmware for smart switches, plugs and sensors, with web UI, MQTT and rules.

  • ESPHome★ 11k

    Describe your device in YAML and get firmware that integrates straight into Home Assistant, no C required.

  • ESPresense★ 1.4k

    Turn ESP32 nodes into a room-level BLE presence-detection network for Home Assistant.

SDKs & languages

  • MicroPython★ 22k

    Run Python 3 directly on the chip with an interactive REPL, great for rapid prototyping.

  • ESP-IDF★ 18k

    Espressif's official IoT development framework (FreeRTOS-based, C/C++); the reference SDK for every modern ESP32-family chip.

  • Arduino-ESP32★ 17k

    The official Arduino core for ESP32 chips; the easiest on-ramp, built on top of ESP-IDF.

  • esp-hal (esp-rs)★ 2.0k

    Bare-metal Rust hardware-abstraction layer for Espressif chips, and the heart of the esp-rs ecosystem.

LED, display & UI

  • WLED★ 18k

    Fast, feature-rich control for addressable LED strips over Wi-Fi, with app, web UI and effects.

Mesh & comms

  • Meshtastic★ 7.8k

    Long-range, off-grid LoRa mesh messaging firmware for ESP32-based radios.

Security research

  • Bruce★ 5.8k

    Predatory ESP32 firmware for offensive-security research on M5Stack and cheap-yellow-display boards.

Open-source projects using this module

Public GitHub projects whose KiCad design files reference the ESP32-C3-WROOM-02.

＋ Add your project

Frequently asked questions

Does the ESP32-C3-WROOM-02 have Wi-Fi and Bluetooth?

It provides 2.4 GHz Wi-Fi 4 and Bluetooth LE.

How much memory does the ESP32-C3-WROOM-02 have?

It comes with 4, 8, 16 MB flash options, and the ESP32-C3 has 400 KB of on-chip SRAM.

How many GPIO pins does the ESP32-C3-WROOM-02 have?

The module breaks out 15 GPIO, with up to 6 12-bit ADC channels. See the full pinout above.

Can I use the ESP32-C3-WROOM-02 with the Arduino IDE?

Yes. Install the Arduino-ESP32 core and pick an ESP32-C3-based board. You can also use ESP-IDF 4.3 or MicroPython.

How do I flash the ESP32-C3-WROOM-02?

The SoC has a built-in USB Serial/JTAG controller, so you can flash and debug over its native USB port with no external adapter.

Is the ESP32-C3-WROOM-02 5 V tolerant?

No. It runs at 3.0-3.6 V and its GPIO are not 5 V tolerant, so level-shift any 5 V signals.

Can I use an external antenna with the ESP32-C3-WROOM-02?

Most Espressif modules are also offered in a "-U" / "-1U" variant that swaps the on-board PCB antenna for a U.FL/IPEX connector, otherwise identical. Check this part's datasheet for the exact variant name.

Further reading