The ESP8266 D1 Mini V4 is a compact WiFi-enabled microcontroller development board based on the ESP8266 family, commonly used with Arduino-style tooling. It connects to a PC via USB for programming/serial communication and provides GPIO pins (3.3 V logic) for controlling peripherals, typically integrating sensors with WiFi for IoT projects.
| Pin | Signal | Description |
|---|---|---|
TX |
TX | UART transmit from ESP8266 for programming and serial output at 3.3V logic. |
RX |
RX | UART receive into ESP8266 for programming and serial input at 3.3V logic. |
GPIO5/SCL |
SCL | ESP8266 GPIO5, commonly D1; default I2C clock line SCL at 3.3V logic. |
GPIO4/SDA |
SDA | ESP8266 GPIO4, commonly D2; default I2C data line SDA at 3.3V logic. |
GPIO0 |
digital | ESP8266 GPIO0, commonly D3; boot-mode pin, low during reset enters flash programming. |
GPIO2 |
digital | ESP8266 GPIO2, commonly D4; boot strap pin and often onboard LED signal. |
GND |
ground | Ground reference for power and 3.3V logic signals. |
VBUS |
power | USB 5V bus supply input/output from the USB connector. |
RST |
reset | Active-low reset input for restarting the ESP8266 module. |
A0 |
analog | Analog input to the onboard ADC; measures a single analog voltage input. |
GPIO16 |
digital | ESP8266 GPIO16, commonly D0; digital I/O and deep-sleep wake connection. |
GPIO14/SCK |
SCK | ESP8266 GPIO14, commonly D5; SPI clock SCK at 3.3V logic. |
GPIO12/MISO |
MISO | ESP8266 GPIO12, commonly D6; SPI MISO data input at 3.3V logic. |
GPIO13/MOSI |
MOSI | ESP8266 GPIO13, commonly D7; SPI MOSI data output at 3.3V logic. |
GPIO15/SS |
SS | ESP8266 GPIO15, commonly D8; SPI slave-select/chip-select and boot strap pin. |
3V3 |
power | Regulated 3.3V supply rail for the ESP8266 and low-current peripherals. |
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