GPIO Pins: NodeMCU has 16 GPIO pins as shown in above diagram which can be used to control other peripheral devices like sensors, LEDs, switches etc. These pins can also be used as PWM pins.
ADC (Analog to Digital Converter) Pin: It has one ADC channel and can be accessed through pin A0.
SPI Pins: There are 4 pins (SCK, MISO, MOSI etc) available for SPI communication as shown in green rectangle in diagram.
I2C Pins: It has I2C functionality support but due to internal use of these pins, you have to find which pin is I2C.
UART Pins: It has two UART interfaces. Since, RXD0 and TXD0 is used to upload codes to board, we cannot use them while programming this module. We can use RXD1 and TXD1 anytime.
This chip enables equipments to connect with internet and make them IoT devices. Now, you can easily open your doors for IoT Projects with the help of this module. This low cost, small size module could do wonders and is really simple and easy to use.
