Manual: Esp8266 Nodemcu Wifi Module User

: 2.4GHz Wi-Fi (802.11 b/g/n) with an integrated PCB antenna.

: Features 16 digital GPIO pins (11 usable) and 1 10-bit analog input (ADC) pin. Power Requirements ESP8266 WiFi Module for Dummies - Instructables ESP8266 NodeMCU WiFi Module User Manual

: Supports UART, SPI, I2C, and I2S communications. and I2S communications.