ESP-WROOM-02
WROOM module · based on ESP8266 (ESP8266EX) · Active unverified
- Xtensa L106
- 1× @ 160 MHz
- Wi-Fi 4
- 2 MB flash
- 11 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 ESP-WROOM-02 is a general-purpose Espressif module built on the ESP8266 single-core Xtensa L106 SoC clocked up to 160 MHz. It pairs 2.4 GHz Wi-Fi 4 with 2 MB flash, routes the radio to a PCB antenna, and breaks out 11 GPIO; the module measures 18 × 20 × 2.8 mm.
It's a lean, low-cost option for simple connected products where board space and BOM cost matter most.
Strapping pins
⚑ flag an errorGPIOs sampled at reset — avoid driving these at power-up.
| Pin | Default | Bit | Function |
|---|---|---|---|
GPIO0 | pull-up | 1 | boot_mode |
GPIO2 | pull-up | 1 | boot |
MTDO | pull-down | 0 | boot |
Compute & memory
⚑ flag an error| CPU | Xtensa L106, 1-core |
|---|---|
| Max clock | 160 MHz |
| SRAM | — KB |
| ROM | — KB |
| Flash options | 2 MB |
| PSRAM | None |
| Co-processor | none |
Wireless
⚑ flag an error| Wi-Fi | Wi-Fi 4 |
|---|---|
| Wi-Fi bands | 2.4GHz |
| Bluetooth | — |
| 802.15.4 (Thread/Zigbee) | No |
| Antenna | PCB |
Peripherals & I/O
⚑ flag an error| Usable GPIO | 11 |
|---|---|
| ADC | 1× 10-bit |
| USB | USB-Serial(external) |
| UART / SPI / I²C / I²S | 2 / 1 / 1 / 1 |
| TWAI (CAN) | No |
| SD/MMC | Yes |
| Ethernet MAC | No |
| Touch | 0 |
Power
⚑ flag an error| Operating voltage | 2.7-3.6 V |
|---|---|
| Deep sleep | 20 µA |
Physical
⚑ flag an error| Dimensions | 18 × 20 × 2.8 mm |
|---|---|
| Pin count | 18 |
| Temp range | -40 to 85 °C |
| Mounting | SMD castellated |
| Lifecycle | Active |
Security
⚑ flag an error| Secure boot | No |
|---|---|
| Flash encryption | No |
| Crypto | — |
| Digital signature | No |
| TRNG | Yes |
Schematics
Mechanical & CAD
Getting started
Frameworks: ESP8266 Arduino core — fully supported · ESP8266 RTOS SDK (Espressif's SDK for the ESP8266) · MicroPython.
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
Public GitHub projects whose KiCad design files reference the ESP-WROOM-02.
- smarthomefans/z2m_partner ★ 189
Hardware module for iobroker.zigbee
- kerikun11/IR-Station ★ 54
Infrared Remote Controller with ESP8266 WiFi-module. You can control your home appliances with your smartphone or laptop.
- Al-Nafuur/United-Carts-of-Atari ★ 40
Firmware for PlusCart and UnoCart
- SpacehuhnTech/deauther-andromeda-pcb ★ 32
The board files for the long range deauther
- Hasenpups/WLED_All-in-one_ESP32_Controller ★ 19
Frequently asked questions
Does the ESP-WROOM-02 have Wi-Fi and Bluetooth?
It provides 2.4 GHz Wi-Fi 4.
How much memory does the ESP-WROOM-02 have?
It comes with 2 MB of flash and the ESP8266 has — KB of on-chip SRAM.
How many GPIO pins does the ESP-WROOM-02 have?
The module breaks out 11 GPIO, with up to 1 10-bit ADC channels. See the full pinout above.
Can I use the ESP-WROOM-02 with the Arduino IDE?
Yes — install the ESP8266 Arduino core and pick an ESP8266-based board. You can also use the ESP8266 RTOS SDK or MicroPython.
How do I flash the ESP-WROOM-02?
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 ESP-WROOM-02 5 V tolerant?
No. It runs at 2.7-3.6 V and its GPIO are not 5 V tolerant — level-shift any 5 V signals.
Can I use an external antenna with the ESP-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 for an external antenna — otherwise identical. Check this part's datasheet for the exact variant name.