The ESP32 and its Pin Description

For IoT projects, we need to use a microcontroller. ESP32 is one such microcontroller that can be used to start learning IOT and making IOT circuits. It is therefore important to learn about its pins layout and also what is the purpose of each pin and how it can be used. In this article, first, the layout of pins available in ESP32 Wroom 30-pin microcontroller is specified. Then the different types of pins that are available in ESP32 are described. ESP32 is used for a variety of applications including the use of wifi, transmitters, and receiver devices, Serial Peripheral Interfaces, analog and digital devices, and lots of sensors.

ESP32 Pins Types Descriptions

Step 1 − Describe the Power Pins of ESP32.

Step 2 − Describe the GPIO Pins of ESP32.

Step 3 − Describe the Analog Pins of ESP32.

Step 4 − Describe the I2C Pins of ESP32.

Step 5 − Describe the DAC Pins of ESP32.

Step 6 − Describe the Touch Pins of ESP32.

Step 7 − Describe the Transmitter and Receiver Pins of ESP32.

Pin Layout of ESP32

This is how an ESP32 wroom 30 pin microcontroller looks like. ESP32 Wroom 30 pin microcontroller has 30 pins with 15 pins on one side and 15 pins on the other side.

Fig: Showing the ESP32 microcontroller with its Pin numbers

The Power Pins of ESP32

ESP32 has 2 GND output pins. It has two pins for positive voltages, Vin and 3V3. Vin can be connected to an external voltage source of 5V to 14V. 3V3 is the pin that can output 3.3 volts and powers the ESP32.

General Purpose Input Output (GPIO) Pins of ESP32

There are 25 GPIO pins in ESP32 wroom 30 pin microcontroller. Although these can be used for different functions, there are some unsafe pins and these should be avoided, for example, RX0 and TX0. The safe-to-use pins are underlined here. All the GPIO pins are listed with GPIO numbers in the following table:

GPIO Pins	ESP32 Pins
GPIO 1	TX0
GPIO 2	D2
GPIO 3	RX0
GPIO 4	D4
GPIO 5	D5
GPIO 12	D12
GPIO 13	D13
GPIO 14	D14
GPIO 15	D15
GPIO 16	RX2
GPIO 17	TX2
GPIO 18	D18
GPIO 19	D19
GPIO 21	D21
GPIO 22	D22
GPIO 23	D23
GPIO 25	D25
GPIO 26	D26
GPIO 27	D27
GPIO 32	D32
GPIO 33	D33
GPIO 34	D34
GPIO 35	D35
GPIO 36	VP
GPIO 39	VN

Analog Pins of ESP32:

SP32 has 15 analog-enabled pins called ADC pins. The Analog to Digital converters ADC1 and ADC2 of ESP32 can be used to map the voltages from 0V to 3.3 V to numbers between 0 to 4096. All the analog pins are listed with numbers in the following table:

Analog Pins	ESP32 Pins
ADC2_0	D4
ADC2_2	D2
ADC1_0	VP
ADC1_3	VN
ADC1_4	D32
ADC1_5	D33
ADC1_6	D34
ADC1_7	D35
ADC1_8	D25
ADC1_9	D26
ADC2_0	D4
ADC2_2	D2
ADC2_3	D15
ADC2_4	D13
ADC2_5	D12
ADC2_6	D14
ADC2_7	D27

I2C (Inter-Integrated Circuit) Interface of ESP32:

I2C interface of ESP32 is used for communications between ESP32 (Master) and sensors (Slaves). For such communications, the ESP32’s D22 and D21 pins are allocated. All the I2C pins are listed with PINs in the following table:

For I2C Communications	ESP32 Pins
SCL	D17
SDA	D16

DAC Pins of ESP32:

DAC Pins	ESP32 Pins
DAC1	D25
DAC2	D26

Touch Pins of ESP32

There are 9 touch pins in ESP32 wroom 30 pin microcontroller. They are listed from Touch 0 to T9 excluding T1 which is not there in the 30-pin microcontroller.

Touch Pins	ESP32 Pins
Touch 0	D4
Touch 2	D2
Touch 3	D15
Touch 4	D13
Touch 5	D12
Touch 6	D14
Touch 7	D27
Touch 8	D33
Touch 9	D32

Transmitter and Receiver Pins of ESP32:

Although ESP32 has three UART (Universal Asynchronous Receiver Transmitter) interfaces, only the following pins of UART2 are safe options to use while using the devices like distance sensors.

In this article, first, the pin diagram of ESP32 wroom 30-pin microcontroller is given. The ESP32 microcontroller can be used for a variety of applications while making IOT circuits. Its pins can be used as GPIO pins, analog pins, touch pins, UART pins, receiver/ transmitter, I2C communications, or for other purposes such as basic power connections. In this article, first, the pin layout is given, then the pins are presented in tabular forms after differentiating these into different categories. Along with the specified purpose for which the pins can be used,

Transmitter/ Receiver Pins	ESP32 Pins
TX2	D22
RX2	D21