The ESP8266 Technical Reference Manual details all GPIO, SDIO, SPI, I2C, I2S, UART, PWM and IR interfaces with register maps and API usage.
This reference guide provides a complete description of the ESP8266EX system‑on‑chip, covering each peripheral interface, its registers, configuration options and example code. It is organized into chapters for GPIO, SDIO, SPI (including HSPI and overlap modes), I2C, I2S, UART, PWM, IR and the Sniffer application.
The document also includes appendices with full register tables for GPIO, SPI, UART and timers, as well as version history and copyright information from Espressif. This manual is written in Chinese.
| GPIO pins | 17 |
|---|---|
| SDIO speed | 25 MHz (v1.1) / 50 MHz (v2.0) |
| SPI interfaces | 1 general SPI, 1 SDIO/SPI slave, 1 HSPI |
The ESP8266EX provides 17 GPIO pins that can be configured for various functions.
It supports 4‑bit SDIO at 25 MHz (v1.1) and up to 50 MHz (v2.0).
The chip includes GPIO, SDIO, SPI (including HSPI and overlap modes), I2C, I2S, UART, PWM, IR and a Sniffer mode.
Register tables for GPIO, SPI, UART and timers are provided in the appendices of the manual.