D1 mini Pro is a wifi board with 16MB flash, external antenna connector and built-in ceramic antenna based on ESP-8266EX Features: 11 digital input/output pins Interrupt/pwm/I2C/one-wire 1 analog input(3.2V max input) 16M bytes(128M bit) Flash External antenna connector Built-in ceramic
WeMos D1 mini pins and diagram
Diagram and pinout for version v1.0.0 Pin Pin Function ESP-8266 Pin TX TXD TXD RX RXD RXD A0 Analog input, max 3.3V input A0 D0 IO GPIO16 D1 IO, SCL GPIO5 D2 IO, SDA GPIO4 D3 IO,10k Pull-up GPIO0 D4