WeMos D1 R2 ESP8266 WiFi UNO Development Board

Microcontroller ESP-8266EX
Operating Voltage 3.3V
Digital I/O Pins 11
Analog Input Pins 1
Clock Speed 80MHz/160MHz
FLash 4M
bytes Length 68.6mm Width 53.4mm
Pin Function ESP-8266 Pin TX TXD TXD RX RXD RXD A0
Analog input, max 3.3V
input A0 D0 IO GPIO16 D1.