ESP Modules

ESP8684-WROOM-03

WROOM module · based on ESP32-C2 (ESP32-C2 (ESP8684)) · Active

  • RISC-V
  • 1× @ 120 MHz
  • Wi-Fi 4
  • BLE 5.x
  • 2 / 4 MB flash
  • 8 GPIO
  • PCB antenna
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Every figure here is checked against Espressif’s official datasheets. We’ve taken every care to keep it accurate — but datasheets are dense and mistakes happen, so if something looks off, please report it.

The ESP8684-WROOM-03 is a general-purpose Espressif module built on the ESP32-C2 single-core RISC-V SoC clocked up to 120 MHz. It pairs 2.4 GHz Wi-Fi 4 and Bluetooth LE with up to 4 MB flash, routes the radio to a PCB antenna, and breaks out 8 GPIO; the module measures 15 × 17.3 × 2.8 mm.

It's a lean, low-cost option for simple connected products where board space and BOM cost matter most. 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.
ESP8684-WROOM-03 pinout diagram — pins colour-coded by function with safe and use-with-care badges
#NameTypeFunctions
1ENI Chip enable ⚑
2IO1I/O/T GPIO1, ADC1_CH1 ⚑
3IO6I/O/T GPIO6, FSPICLK, MTCK ⚑
4IO7I/O/T GPIO7, FSPID, MTDO ⚑
5IO3I/O/T GPIO3, ADC1_CH3 ⚑
63V3P Power supply ⚑
7GNDP Ground ⚑
8IO10I/O/T GPIO10, FSPICS0, UART1_RXD ⚑
9IO18I/O/T GPIO18, UART1_TXD ⚑
10IO5I/O/T GPIO5, FSPIWP, MTDI ⚑
11IO4I/O/T GPIO4, ADC1_CH4, FSPIHD, MTMS ⚑
Official datasheet pin-layout figure
ESP8684-WROOM-03 datasheet pin layout (top view)

Find a pin by function

Pick a capability to see which GPIOs provide it on the ESP32-C2.

Freely usable, no special role.

GPIO1general-purpose
GPIO3general-purpose
GPIO10general-purpose
GPIO18general-purpose

UART, I²C, SPI (master), I²S, PWM/LEDC and most digital peripherals route through the GPIO matrix — 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
GPIO8n/a—boot
GPIO9pull-up1boot_mode

GPIO pin warnings

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On the ESP32-C2, 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
GPIO4JTAG
GPIO5JTAG
GPIO6JTAG
GPIO7JTAG

Compute & memory

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CPURISC-V, 1-core
Max clock120 MHz
SRAM272 KB
ROM576 KB
Flash options2 / 4 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 GPIO8
ADC5× 12-bit
USBUSB-Serial(external)
UART / SPI / I²C / I²S2 / 1 / 1 / 0
TWAI (CAN)No
SD/MMCNo
Ethernet MACNo
Touch0

Power

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Operating voltage3.0-3.6 V
Deep sleep5 µA

Physical

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Dimensions15 × 17.3 × 2.8 mm
Pin count11
Temp range-40 to 105 °C
MountingSMD castellated
LifecycleActive

Security

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Secure bootYes
Flash encryptionYes
CryptoECC, SHA, RNG
Digital signatureNo
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
ESP8684-WROOM-03-H2X 2 MB — −40 to 105 °C
ESP8684-WROOM-03-H4X 4 MB — −40 to 105 °C

Schematics

ESP8684-WROOM-03 module reference-design schematic
Module reference design
ESP8684-WROOM-03 peripheral / application schematic showing how to wire the module
Peripheral / application circuit — how to wire it up

Mechanical & CAD

ESP8684-WROOM-03 physical dimensions drawing
Physical dimensions
ESP8684-WROOM-03 recommended PCB land pattern
Recommended PCB land pattern

Getting started

Frameworks: Arduino-ESP32 core — partial support · ESP-IDF 5.0+ (Espressif's official SDK) · MicroPython.

ESP-IDF target: idf.py set-target esp32c2.

Programming uses UART — most dev boards include a USB-to-UART bridge; for the bare module add your own (e.g. CP2102/CH340).

Open-source projects using this module

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Frequently asked questions

Does the ESP8684-WROOM-03 have Wi-Fi and Bluetooth?

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

How much memory does the ESP8684-WROOM-03 have?

It comes with 2, 4 MB flash options and the ESP32-C2 has 272 KB of on-chip SRAM.

How many GPIO pins does the ESP8684-WROOM-03 have?

The module breaks out 8 GPIO, with up to 5 12-bit ADC channels. See the full pinout above.

Can I use the ESP8684-WROOM-03 with the Arduino IDE?

Arduino-ESP32 core support is partial; ESP-IDF 5.0 is the most complete option.

How do I flash the ESP8684-WROOM-03?

Programming uses UART — most dev boards include a USB-to-UART bridge; for the bare module add your own (e.g. CP2102/CH340).

Is the ESP8684-WROOM-03 5 V tolerant?

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

Can I use an external antenna with the ESP8684-WROOM-03?

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

Further reading