ESP32 S2 Development Board : PinOut, Features, Specifications, Components, Interfacing, Datasheet & Its Applications

The ESP32-S2 is a highly capable microcontroller from the ESP32 family, developed by Espressif with key enhancements to use in IoT and embedded systems. It provides a balance between power efficiency, performance & connectivity options. This is a versatile and powerful development board that offers excellent security features and the convenience of USB OTG. Engineers developed the ESP32-S2 board to deliver a secure, flexible, and power-efficient solution for IoT applications. It features Wi-Fi connectivity, a wide range of peripherals, and enhanced USB capabilities. This board is a great choice for developers who are looking to design scalable and low-cost devices. This article elaborates on the ESP32 S2 development board, its working, and its applications.

What is the ESP32 S2 Development Board?

An ESP32 S2 is a single-core, 32-bit Xtensa processor development board that creates and tests IoT devices & embedded systems. ESP32-S2 development board provides Wi-Fi (802.11 b/g/n) mainly for wireless communication to use in networking applications. This board has some features like integrated USB-to-UART converters, JTAG debugging, and a variety of I/O pins to help in development.

ESP32 S2 Development Board examples mainly include: ESP32-S2-DEVKITC-1U, ESP32-S2-DevKitC-1, and Arduino Nano ESP32. These boards are normally open-source, with broad documentation & available libraries. So these are commonly used in IoT projects like robotics, smart home devices, wearables, etc.

How ESP32-S2 Development Board Work?

The ESP32-S2 development board works by using an ESP32-S2 SoC to integrate a Wi-Fi subsystem & other peripherals to use in different applications like IoT. This board processes data using the ESP32-S2 chip, which includes an Xtensa 32-bit LX7 CPU and then uses its on-chip memory, peripherals, and wireless communication capabilities to interact with the external world. It is designed to be a highly integrated and low-power platform by providing a set of I/O capabilities. So this board is user-friendly and easily interfaced with other components.

Pin Configuration:

The pin configuration of the ESP32 S2 development board is shown below. This board includes several analog and digital I/O pins like 45 GPIOs, 26 PWM-enabled pins, and 20 ADC channels. However, the pin configuration and its functionality can change slightly based on the type of development board.

Power Pins:

The power pins on the ESP32 S2 development board include VIN, 3V3, and GND, each serving a specific purpose.

• The VIN pin allows you to power the development board directly with a 5V regulated supply.
• 3V3 pin provides 3.3V regulated output, normally used to provide power supply to the ESP32 chip & its peripherals. So it supplies up to 600mA of power.
• This GND pin serves as the common GND for all power & logic.

GPIO Pins

The ESP32-S2 development board includes around 43 GPIO pins, which range from GPIO0 to GPIO21 & GPIO26 to GPIO46 according to Espressif. Each GPIO pin on this development board can connect to various internal peripherals, including I2S, SPI, UART, touch sensors, PWM, and I2C. Many GPIO pins can also function as external interrupt pins, while some are primarily designated for analog input.

Enable (EN) Pin

This enables or stops the ESP32 chip. By default, you can pull this pin high to enable the chip. Pulling it low disables the chip and prevents it from triggering a reset..

Strapping Pins

The strapping pins of this board mainly include GPIO0, GPIO2, GPIO4, GPIO5, GPIO12 & GPIO15. These pins can be used to configure the boot mode of the chip. These pins are read in startup, and after that, they can be used as regular GPIO pins once the chip has booted.

ADC Channels

This board includes 20 ADC channels, including 2 SAR ADCs, which support a 12-bit resolution.

PWM

It includes 26 PWM pins, which are capable of PWM (Pulse Width Modulation):

External Interrupts

This development board offers a variety of GPIO pins that can be configured as external interrupt pins.

RTC GPIOs

Furthermore, certain RTC GPIO pins are specifically designed for low-power operation during deep sleep mode.

Touch Sensor Pins

The ESP32-S2 board includes 10 capacitive touch-sensitive GPIO pins that detect changes in capacitance when a finger contacts them. These pins can implement touch controls.

Special Function Pins:

• GPIO pins 26 to 32 serve special functions and are typically reserved for PSRAM and SPI flash, as recommended by Espressif, so it’s best not to use them for other purposes.
• Pins GPIO 39 to 42 are primarily designated for JTAG debugging, while GPIO 46 is fixed for pull-down and functions as an input only.
• Additionally, RTC GPIO pins represent a subset of GPIOs that can operate as low-power digital I/Os during deep sleep mode.

Features and Specifications:

The features and specifications of the ESP32 S2 development board include the following.

• Buy ESP32-S2 is a low-power, highly integrated, and single-core Wi-Fi-based microcontroller SoC.
• It is developed by Espressif Systems.
• Operating voltage ranges from 3.0 V to 3.6 V.
• It is available in the QFN package.
• The ESP32 S2 development board includes a single-core Xtensa LX7 processor, 2.4 GHz Wi-Fi & a low-power co-processor.
• It provides consistent wireless connectivity through its incorporated Wi-Fi (IEEE 802.11 b/g/n), which supports a variety of bandwidths & Infrastructure Station, Promiscuous, and SoftAP modes.
• This board includes SRAM of 320KB, ROM of 128KB, PSRAM of 8MB, and flash memory of 4MB/8 MB.
• The clock speed is 240 MHz.
• This board provides a wide range of peripherals like 43 GPIOs and digital Interfaces like SPI-4, I2C-2, I2S-2, RMT-1 & UART-2.
• It includes a 12-bit ADC with up to 18 channels, 8-bit DACs & LED PWM controller.
• It includes 10 touch sensor inputs.
• Operating temperature ranges from -40°C to +85°C.
• This board has an in-built USB-to-serial converter which simplifies programming & debugging.
• It is optimized for low-power applications like battery-powered devices.
• This board is compatible with Arduino, MicroPython, and ESP-IDF.
• It has some security features like flash encryption and secure boot to defend firmware & data.
• This board has mounting hardware that can be extended with other peripherals throughout its different interfaces.

ESP32 S2 Development Board Hardware

ESP32 S2 development board includes different components, which are discussed below.

ESP32-S2-SOLO/ESP32-S2-SOLO-U On-board Module

ESP32-S2-SOLO series modules have an on-board PCB antenna; otherwise, a connector is mainly for an external antenna. These on-board modules have various options for PSRAM & flash size

3.3 Volts Power On LED

This LED turns on whenever the USB power is connected to the development board.

USB-to-UART Bridge

This is a single-type USB-to-UART bridge chip that provides transfer rates equal to 3 Mbps.

Pin Headers

The available GPIO pins, excluding those used for the SPI bus for flash, are accessible through the pin headers on the development board.

ESP32-S2 USB Port

The full-speed ESP32-S2 USB OTG interface is compliant with the USB 1.1 specifications. This interface provides a power supply to the development board, for flashing applications to the chip, & for communication through USB 1.1 protocols with the chip.

Reset Button

Pressing this button restarts the system.

Boot Button

You can use the Boot button on this development board to enter firmware download mode, allowing you to upload new code. This button connects to GPIO0, which must be low during the reset to activate the boot loader.

USB-to-UART Port

The micro-USB port supplies power to the development board during flashing applications, while communication with the chip occurs through the onboard USB-to-UART Bridge.

RGB LED

This is an addressable RGB LED that is driven through GPIO18.

5 Volts to 3.3 Volts LDO

It is a low-dropout power regulator that changes a 5-volt input supply into a 3.3-volt output supply.

Comparison of ESP32 S2 Vs ESP32 S3

The difference between ESP32 S2 and ESP32 S3 development boards is discussed below.

ESP32 S2	ESP32 S3
ESP32-S2 development board is a single-core microcontroller.	ESP32-S3 development board is a dual-core microcontroller.
The camera interface is not available.	Camera interface is available.
Flash memory is up to 4 MB.	Its flash memory is up to 16 MB.
It doesn’t have PSRAM.	Its PSRAM is up to 8 MB.
Bluetooth is not available.	This board uses Bluetooth 5.0.
It has some security features like: RSA-3072, HMAC, AES-256 & digital signature.	Its security features are: RSA-4096, AES-256, HMAC & digital signature.
It has low power consumption.	It has high power consumption.
These are not AI-capable boards.	These are AI-capable boards.
ESP32 S2 board applications are: IoT, Industrial, Secure IoT, etc.	ESP32  S3 board applications are: advanced IoT, AI, multimedia, etc.

Maintenance

ESP32-S2 development board maintenance mainly involves keeping the hardware & software in good condition.

• So its maintenance regularly includes ensuring the correct power supply, reset & boot modes handling properly, and maintaining the software up-to-date.
• In addition, it is significant to be aware of environmental factors like electrostatic discharge and temperature.
• Check the development board frequently for any physical injuries like cracked solder joints, broken components, and pins.
• Software maintenance of this development board involves firmware updates, ESP-IDF setup, code optimization, and testing.
• The ESP32-S2 development board troubleshooting mainly involves: power issues, communication issues, firmware issues, and community support.

ESP32 S2 Development Board with SHT21 Temperature Sensor

Here we will discuss how to connect the ESP32-S2 development board with the SHT21 temperature sensor. In this setup, the SHT21 serves as a temperature and humidity sensor, operating at 3.3 volts and communicating through the I2C protocol. The SHT21 sensor reads temperatures from -40ºC and +120ºC, whereas humidity is between 0% to 100%.

The required components to make this interfacing mainly include: an ESP32 S2 development board, an SHT21 temperature sensor, and connecting wires. The connections of this interfacing follow as;

• Connect the 3V3 pin of the ESP32 S2 development board to the Vin pin of the SHT21 temperature sensor.
• Connect the GND pin of the ESP32 S2 development board to the GND pin of the SHT21 temperature sensor.
• Connect the SCL pin of the development board to the SCL pin of the sensor.
• Connect the SDA pin of the development board to the SDA pin of the sensor.

Code:

Below, you will find the necessary code for the ESP32 S2 development board paired with the SHT21 temperature sensor.

#include <SHT21.h> // include SHT21 library
SHT21 sht;
float temp; // variable to store temperature
float humidity; // variable to store hemidity
void setup() {
Wire.begin(); // begin Wire(I2C)
Serial.begin(9600); // begin Serial
}
void loop() {
temp = sht.getTemperature(); // get temp from SHT
humidity = sht.getHumidity(); // get temp from SHT
Serial.print(“Temp: “); // print readings
Serial.print(temp);
Serial.print(“\t Humidity: “);
Serial.println(humidity);
delay(500); // min delay for 14bit temp reading is 85ms
}

Working

First, download the library from GitHub for the Arduino board. Once you have the code, open the Arduino IDE, navigate to Sketch, select Add Library, and then choose Add ZIP Library. After that, locate and select the downloaded ZIP file.

To open the code example, click on File, then Examples, followed by STH21-Arduino-Library, and select SHT21_Demo. Click the arrow “->” in the Arduino IDE and wait for the program to upload to the Franzininho WiFi. You will then see the results on the serial monitor, which displays the nearby temperature and humidity every half second.

Advantages

The ESP32-S2 development board offers several benefits, which I will outline below.

• With its single-core processor, the ESP32-S2 development board is designed for energy-efficient operation, making it perfect for battery-powered applications.
• Additionally, the ESP32-S2 board excels in HMI applications, such as touchpad and touchscreen-based devices.
• This board has a major increase in GPIO pins as compared to the unique ESP32 board, with up to 43 available for connecting actuators, sensors & other peripherals.
• The built-in USB OTG interface allows the board to communicate directly with other USB devices by removing the requirement for a separate USB-to-serial converter.
• It incorporates a wide range of peripherals with flexibility, like a camera interface, LCD interface, SPI, UART, I2S, ADC, and DAC.
• This ESP32-S2 development board supports 2.4 GHz WI-Fi with HT40/ HT20 BW by ensuring consistent wireless connectivity
• These are cost-effective boards that are attractive options for both professional and hobbyist developers.
• This board can reliably operate in a wide temperature range from 40 °C to +105°C.
• This development board provides onboard resources and peripheral interfaces that ease quick secondary development for a variety of functions.

Disadvantages

The ESP32-S2 development board has several drawbacks, which are discussed below.

• The ESP32-S2 development board does not support Bluetooth.
• It has a complex CPU Architecture.
• Its I2C speed is limited.
• There have been potential Wi-Fi problems, like weak signal strength and complexity in access point detection.
• It doesn’t have hardware safety features and has potential problems with USB connectivity & RF performance.
• It is a single-core microcontroller that impacts the performance potentially in some applications.

Applications

The ESP32-S2 development board applications include the following.

• Smart homes utilize this technology to control appliances, lighting, security systems, thermostats, and more.
• Wearable technology developers use this board to create fitness trackers, smartwatches, health monitors, and other devices.
• In industrial automation, this board helps build PLCs, data loggers, sensor networks, and similar systems.
• This board actively monitors and controls energy consumption in buildings and homes.
• Security systems rely on this technology to create alarm systems, smart locks, and surveillance cameras.
• Robotics engineers use this board to control robotic movements and sensors.
• In audio and video processing, this board enables audio streaming and enhances video processing capabilities.
• Educators employ this board in projects to teach about wireless communication, microcontrollers, embedded systems, and more.
• It offers a convenient method for developers to create and test new software and hardware solutions.

Thus, this is an overview of the ESP32-S2 development board, which is a popular choice for embedded systems and IoT applications because of its Wi-Fi connectivity, security features, and low power consumption. This is a versatile development board, thus development of an extensive range of connected devices. Here is a question for you: What is IoT?