Esp8266 Esp-01 Datasheet Updated Jun 2026

⚠️ Do use 5V logic levels. Use a level shifter or voltage divider for 5V UART signals.

| Pin # | Name | Type | Function | Critical Notes | | :--- | :--- | :--- | :--- | :--- | | | GPIO0 | I/O | General Purpose / Boot Mode | Boot config: Low = Flash mode, High = Run mode. | | 2 | RXD | Input | UART Receive (3.3V logic) | Connect to TX of USB-Serial adapter. | | 3 | TXD | Output | UART Transmit (3.3V logic) | Connect to RX of USB-Serial adapter. | | 4 | CH_PD | Input | Chip Enable | Must be HIGH (3.3V) for chip to turn on. | | 5 | GPIO2 | I/O | General Purpose / Boot | Must be HIGH (pull-up) during boot. | | 6 | RST | Input | Reset (Active LOW) | Pull LOW to reboot the chip. | | 7 | VCC | Power | 3.3V Input | Do NOT use 5V. Max 3.6V. | | 8 | GND | Power | Ground (0V) | Common ground with serial adapter. | esp8266 esp-01 datasheet

The ESP-01 module features 8 interface pins in a dual-in-line arrangement. Understanding these pins is crucial for power, programming, and operation. ⚠️ Do use 5V logic levels