The ESP8266 chip (a 32-bit processor) controls the board, which has a greater flash memory than an Arduino Uno.
This board works with both the Arduino IDE and NodeMCU. The D1 R2 also has an integrated switching power supply, allowing it to be powered from a power supply up to a 12V DC supply.
USB to Serial converter CH340G IC available on the board.
The ESP8266 is a popular microcontroller with built-in WiFi that is similar to Arduino. The power and programming connections on most ESP8266 ESP-12 boards are inconvenient. You'll need to figure out how to provide 3.3V. These boards take care of that by breaking out the pins to the common Arduino UNO design, allowing you to utilise DuPont cables and even UNO shields directly (if compatible).
|Digital I/O Pins||11|
|Analog I/O Pin||1|
|Flash Memory||4 MB|