ESP8266 Boards

Three popular boards built around the ESP8266 (Xtensa LX106 at 80 MHz, 3.3 V). They are compiled with the official ESP8266 Arduino core 3.1.2 and simulated by an LX106 emulator based on esp8266js, extended for the Arduino core.

Common features

Feature	Details
Logic level	3.3 V
Pin names in code	Board names (`D1`, `D5`, `A0`) or GPIO numbers (`5`, `14`)
Digital pins	D0–D8, RX and TX
Analog input	A0 (0–3.3 V, 0–1023)
PWM, `tone()`, Servo	On D1–D8
I²C	`Wire` on D2 (SDA) and D1 (SCL)
SPI	D5 (SCK), D6 (MISO), D7 (MOSI), D8 (SS)
Serial Monitor	`Serial` (TX/RX)
Built-in LED	D4 (GPIO 2), lit when the pin is LOW

Also simulated: interrupts, SoftwareSerial, NeoPixel, DHT, DS18B20, EEPROM and every component block.

GPIO mapping

Board pin	GPIO	Notes
D0	16	No pull-up, no interrupts
D1	5	I²C SCL
D2	4	I²C SDA
D3	0	Boot mode pin on real boards
D4	2	Built-in LED, boot mode pin
D5	14	SPI SCK
D6	12	SPI MISO
D7	13	SPI MOSI
D8	15	SPI SS, boot mode pin
RX	3	Serial
TX	1	Serial
A0	ADC	Analog input only

Boards

NodeMCU V3 (LoLin) ESP8266 (ESP-12E)

The most common ESP8266 board, WiFi, 11 GPIO pins, 3.3 V.

The NodeMCU V3 (LoLin) is the wide version of the NodeMCU with the ESP-12E module, a CP2102 USB chip and an AMS1117 regulator. The RSV pins are not connected.

NodeMCU Amica (V2) ESP8266 (ESP-12E)

Slim NodeMCU that fits on a breadboard, WiFi, 3.3 V.

The NodeMCU Amica (V2) is the narrow version that fits on a breadboard with free holes on both sides. Its pinout is the same as the V3.

WEMOS D1 Mini ESP8266EX

Tiny ESP8266 board, WiFi, 11 GPIO pins, 3.3 V.

The WEMOS D1 Mini is a tiny board with 16 pins and the ESP-8266EX on a shielded module. It is compiled as the d1_mini board.

Default pins used by blocks

The three boards use the same defaults. Bluetooth and GPS use SoftwareSerial.

Boot messages

Before your program starts, the Espressif SDK prints its version (SDK ver: 2.2.2 …) to the Serial Monitor, as on a real board.

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