ESPRESSIF ESP32-S2-MINI-2 WiFi Module User Manual

June 10, 2024
ESPRESSIF

ESPRESSIF ESP32-S2-MINI-2 WiFi Module logo

ESPRESSIF ESP32-S2-MINI-2 WiFi Module

ESPRESSIF ESP32-S2-MINI-2 WiFi Module 22.4 GHz Wi-Fi (802.11 b/g/n) module
Built around ESP32-S2 series of SoC (chip revision v1.0), Xtensa® single-core 32-bit LX7 mi-coprocessor
4 MB flash and optional 2 MB PSRAM in chip package
37 GPIOs, rich set of peripherals
On-board PCB antenna

Module Overview

ESP32-S2-MINI-2 is a general-purpose Wi-Fi module. The rich set of peripherals and a small size make this module an ideal choice for smart homes, industrial automation, health care, consumer electronics, etc.
SP32-S2-MINI-2 Specifications

Categories Parameters Specifications
Wi-Fi Protocols 802.11 b/g/n (up to 150 Mbps)
Frequency range 2412 ~ 2462 MHz
Hardware Module interfaces GPIO, SPI, I2S, UART, I2C, LED PWM, TWAI®, LCD,

Camera interface, ADC, DAC, touch sensor, temperature sensor, USB OTG
Integrated crystal| 40 MHz crystal
Operating voltage/Power supply| 3.0 V ~ 3.6 V
Operating current| Average: 80 mA
Minimum current delivered by power supply| 500 mA
Ambient temperature| –40 °C ~ +85 °C/105 °C
Moisture sensitivity level (MSL)| Level 3

Pin Definitions

Pin Layout

The pin diagram below shows the approximate location of pins on the module.
Pin Layout (Top View)
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 1

Pin Description

The module has 65 pins.
For peripheral pin configurations, please refer to ESP32-S2 Series Datasheet.
Pin Definitions

Name No. Type 1 Function
1, 2, 30,
GND 42, 43, P Ground
46-65
3V3 3 P Power supply
Name No. Type 1 Function
--- --- --- ---
IO0 4 I/O/T RTC_GPIO0, GPIO0
IO1 5 I/O/T RTC_GPIO1, GPIO1, TOUCH1, ADC1_CH0
IO2 6 I/O/T RTC_GPIO2, GPIO2, TOUCH2, ADC1_CH1
IO3 7 I/O/T RTC_GPIO3, GPIO3, TOUCH3, ADC1_CH2
IO4 8 I/O/T RTC_GPIO4, GPIO4, TOUCH4, ADC1_CH3
IO5 9 I/O/T RTC_GPIO5, GPIO5, TOUCH5, ADC1_CH4
IO6 10 I/O/T RTC_GPIO6, GPIO6, TOUCH6, ADC1_CH5
IO7 11 I/O/T RTC_GPIO7, GPIO7, TOUCH7, ADC1_CH6
IO8 12 I/O/T RTC_GPIO8, GPIO8, TOUCH8, ADC1_CH7
IO9 13 I/O/T RTC_GPIO9, GPIO9, TOUCH9, ADC1_CH8, FSPIHD
IO10 14 I/O/T RTC_GPIO10, GPIO10, TOUCH10, ADC1_CH9, FSPICS0, FSPIIO4
IO11 15 I/O/T RTC_GPIO11, GPIO11, TOUCH11, ADC2_CH0, FSPID, FSPIIO5
IO12 16 I/O/T RTC_GPIO12, GPIO12, TOUCH12, ADC2_CH1, FSPICLK, FSPIIO6
IO13 17 I/O/T RTC_GPIO13, GPIO13, TOUCH13, ADC2_CH2, FSPIQ, FSPIIO7
IO14 18 I/O/T RTC_GPIO14, GPIO14, TOUCH14, ADC2_CH3, FSPIWP, FSPIDQS
IO15 19 I/O/T RTC_GPIO15, GPIO15, U0RTS, ADC2_CH4, XTAL_32K_P
IO16 20 I/O/T RTC_GPIO16, GPIO16, U0CTS, ADC2_CH5, XTAL_32K_N
IO17 21 I/O/T RTC_GPIO17, GPIO17, U1TXD, ADC2_CH6, DAC_1
IO18 22 I/O/T RTC_GPIO18, GPIO18, U1RXD, ADC2_CH7, DAC_2, CLK_OUT3
IO19 23 I/O/T RTC_GPIO19, GPIO19, U1RTS, ADC2_CH8, CLK_OUT2, USB_D-
IO20 24 I/O/T RTC_GPIO20, GPIO20, U1CTS, ADC2_CH9, CLK_OUT1, USB_D+
IO21 25 I/O/T RTC_GPIO21, GPIO21
IO26 2 26 I/O/T SPICS1, GPIO26
NC 27 NC
IO33 28 I/O/T SPIIO4, GPIO33, FSPIHD
IO34 29 I/O/T SPIIO5, GPIO34, FSPICS0
IO35 31 I/O/T SPIIO6, GPIO35, FSPID
IO36 32 I/O/T SPIIO7, GPIO36, FSPICLK
IO37 33 I/O/T SPIDQS, GPIO37, FSPIQ
IO38 34 I/O/T GPIO38, FSPIWP
IO39 35 I/O/T MTCK, GPIO39, CLK_OUT3
IO40 36 I/O/T MTDO, GPIO40, CLK_OUT2
IO41 37 I/O/T MTDI, GPIO41, CLK_OUT1
IO42 38 I/O/T MTMS, GPIO42
TXD0 39 I/O/T U0TXD, GPIO43, CLK_OUT1
RXD0 40 I/O/T U0RXD, GPIO44, CLK_OUT2
IO45 41 I/O/T GPIO45
IO46 44 I GPIO46
EN 45 I High: on, enables the chip. Low: off, the chip powers off.

Note: Do not leave the EN pin floating.

  1. 1 P: power supply; I: input; O: output; T: high impedance.
  2. 2 IO26 is used by the embedded PSRAM on the ESP32-S2-MINI-2-N4R2 module, and cannot be used for other purposes.

Get Started

What You Need

To develop applications for module you need:

  • 1 x ESP32-S2-MINI-2
  • 1 x Espressif RF testing board
  • 1 x USB-to-Serial board
  • 1 x Micro-USB cable
  • 1 x PC running Linux

In this user guide, we take Linux operating system as an example. For more information about the configuration on Windows and macOS, please refer to ESP- IDF Programming Guide.

Hardware Connection
  1. Solder the ESP32-S2-MINI-2 module to the RF testing board.ESPRESSIF ESP32-S2-MINI-2 WiFi Module 2
  2. Connect the RF testing board to the USB-to-Serial board via TXD, RXD, and GND.
  3. Connect the USB-to-Serial board to the PC.
  4. Connect the RF testing board to the PC or a power adapter to enable 5 V power supply, via the Micro-USB cable.
  5. During download, connect IO0 to GND via a jumper. Then, turn ”ON” the testing board.
  6. Download firmware into flash. For details, see the sections below.
  7. After download, remove the jumper on IO0 and GND.
  8. Power up the RF testing board again. The module will switch to working mode. The chip will read programs from flash upon initialization.

Note:
IO0 is internally logic high. If IO0 is set to pull-up, the Boot mode is selected. If this pin is pull-down or left floating, the Download mode is selected. For more information on ESP32-S2-MINI-2, please refer to ESP32-S2 Series Datasheet.

Set up Development Environment

The Espressif IoT Development Framework (ESP-IDF for short) is a framework for developing applications based on the Espressif SoCs. Users can develop applications with ESP32-S2 in Windows/Linux/macOS based on ESP-IDF. Here we take Linux operating system as an example.
Install Prerequisites
To compile with ESP-IDF you need to get the following packages:

  • CentOS 7 & 8:
    ESPRESSIF ESP32-S2-MINI-2 WiFi Module 3

  • Ubuntu and Debian:ESPRESSIF ESP32-S2-MINI-2 WiFi Module 4

  • Arch:ESPRESSIF ESP32-S2-MINI-2 WiFi Module 5

Note:

  • This guide uses the directory ~/esp on Linux as an installation folder for ESP-IDF.
  • Keep in mind that ESP-IDF does not support spaces in paths.

Get ESP-IDF
To build applications for ESP32-S2-MINI-2 module, you need the software libraries provided by Espressif in ESP-IDF repository.
To get ESP-IDF, create an installation directory (~/esp) to download ESP-IDF to and clone the repository with ‘git clone’:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 6ESP-IDF will be downloaded into ~/esp/esp-idf. Consult ESP-IDF Versions for information about which ESP-IDF version to use in a given situation.
Set up Tools
Aside from the ESP-IDF, you also need to install the tools used by ESP-IDF, such as the compiler, debugger, Python packages, etc. ESP-IDF provides a script named ’install.sh’ to help set up the tools in one go.
Set up Environment Variables
The installed tools are not yet added to the PATH environment variable. To make the tools usable from the command line, some environment variables must be set. ESP-IDF provides another script ’export.sh’ which does that. In the terminal where you are going to use ESP-IDF, run:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 8Now everything is ready, you can build your first project on ESP32-S2-MINI-2 module.

Create Your First Project

Start a Project
Now you are ready to prepare your application for ESP32-S2-MINI-2 module. You can start with get-started/hello_world project from examples directory in ESP- IDF.
Copy get-started/hello_world to ~/esp directory:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 9There is a range of example projects in the examples directory in ESP-IDF. You can copy any project in the same way as presented above and run it. It is also possible to build examples in-place, without copying them
first.
Connect Your Device
Now connect your module to the computer and check under what serial port the module is visible. Serial ports in Linux start with ‘/dev/tty’ in their names. Run the command below two times, first with the board unplugged, then with plugged in. The port which appears the second time is the one you need:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 10 Note:
Keep the port name handy as you will need it in the next steps.
Configure
Navigate to your ‘hello_world’ directory from Step 3.4.1. Start a Project, set ESP32-S2 chip as the target and run the project configuration utility ‘menuconfig’.
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 11Setting the target with ‘idf.py set-target ESP32-S2’ should be done once, after opening a new project. If the project contains some existing builds and configuration, they will be cleared and initialized. The target may be saved in environment variable to skip this step at all. See Selecting the Target for additional information.
If the previous steps have been done correctly, the following menu appears:
Project Configuration – Home Window
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 12
You are using this menu to set up project specific variables, e.g. Wi-Fi network name and password, the processor speed, etc. Setting up the project with menuconfig may be skipped for “hello_world”. This example will run with default configuration
The colors of the menu could be different in your terminal. You can change the appearance with the option ‘–style’. Please run ‘idf.py menuconfig –help’ for further information.
Build the Project
Build the project by running:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 13This command will compile the application and all ESP-IDF components, then it will generate the bootloader, partition table, and application binaries.
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 14 ESPRESSIF ESP32-S2-MINI-2 WiFi Module 15If there are no errors, the build will finish by generating the firmware binary .bin file.
Flash onto the Device
Flash the binaries that you just built onto your module by running:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 16Replace PORT with your ESP32-S2 board’s serial port name from Step: Connect Your Device.
You can also change the flasher baud rate by replacing BAUD with the baud rate you need. The default baud rate is 460800.
For more information on idf.py arguments, see idf.py.
Note:
The option ‘flash‘ automatically builds and flashes the project, so running ‘idf.py build‘ is not necessary.
When flashing, you will see the output log similar to the following:
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 17
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 18
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 19If there are no issues by the end of the flash process, the board will reboot and start up the “hello_world” application.
Monitor
To check if “hello_world” is indeed running, type ‘idf.py -p PORT monitor‘ (Do not forget to replace PORT with your serial port name).
This command launches the IDF Monitor application:ESPRESSIF ESP32-S2-MINI-2
WiFi Module 20
After startup and diagnostic logs scroll up, you should see “Hello world!” printed out by the application.
ESPRESSIF ESP32-S2-MINI-2 WiFi Module 22To exit IDF monitor use the shortcut Ctrl+].
That’s all what you need to get started with ESP32-S2-MINI-2 module! Now you are ready to try some other examples in ESP-IDF, or go right to developing your own applications.

U.S. FCC Statement

The device complies with KDB 996369 D03 OEM Manual v01. Below are integration instructions for host product manufacturers according to the KDB 996369 D03 OEM Manual v01.
List of Applicable FCC Rules
FCC Part 15 Subpart C 15.247
Specific Operational Use Conditions
The module has WiFi functions.

  • Operation Frequency:
    • WiFi: 2412 ~ 2462 MHz
  • Number of Channel:
    • WiFi: 11
  • Modulation:
    • WiFi: DSSS; OFDM
  • Type: On-board PCB antenna
  • Gain: 4.54 dBi Max

The module can be used for IoT applications with a maximum 4.54 dBi antenna. The host manufacturer installing this module into their product must ensure that the final composite product complies with the FCC requirements by a technical assessment or evaluation to the FCC rules, including the transmitter operation. The host manufacturer has to be aware not to provide information to the end user regarding how to install or remove this RF module in the user’s manual of the end product which integrates this module. The end user manual shall include all required regulatory information/warning as show in this manual.
Limited Module Procedures
Not applicable. The module is a single module and complies with the requirement of FCC Part 15.212.
Trace Antenna Designs
Not applicable. The module has its own antenna, and does not need a host’s printed board microstrip trace antenna, etc.
RF Exposure Considerations
The module must be installed in the host equipment such that at least 20cm is maintained between the antenna and users’ body; and if RF exposure statement or module layout is changed, then the host product manufacturer required to take responsibility of the module through a change in FCC ID or new application. The FCC ID of the module cannot be used on the final product. In these circumstances, the host manufacturer will be responsible for re- evaluating the end product (including the transmitter) and obtaining a separate FCC authorization.
Antennas
Antenna specification are as follows:

  • Type: On-board PCB antenna
  • Gain: 4.54 dBi

This device is intended only for host manufacturers under the following conditions:

  • The transmitter module may not be co-located with any other transmitter or antenna.
  • The module shall be only used with the external antenna(s) that has been originally tested and certified with this module.
  • The antenna must be either permanently attached or employ a ‘unique’ antenna coupler.

As long as the conditions above are met, further transmitter test will not be required. However, the host manufacturer is still responsible for testing their end-product for any additional compliance requirements required with this module installed (for example, digital device emissions, PC peripheral requirements, etc.).
Label and Compliance Information
Host product manufacturers need to provide a physical or e-label stating “Contains FCC ID:
2AC7Z-ESPS2MINI2” with their finished product.
Information on test modes and additional testing requirements

  • Operation Frequency:
    • WiFi: 2412 ~ 2462 MHz
  • Number of Channel:
    • WiFi: 11
  • Modulation:
    • WiFi: DSSS; OFDM

Host manufacturer must perform test of radiated and conducted emission and spurious emission, etc., according to the actual test modes for a stand-alone modular transmitter in a host, as well as for multiple simultaneously transmitting modules or other transmitters in a host product. Only when all the test results of test modes comply with FCC requirements, then the end product can be sold legally.
Additional testing, Part 15 Subpart B compliant
The modular transmitter is only FCC authorized for FCC Part 15 Subpart C 15.247 and that the host product manufacturer is responsible for compliance to any other FCC rules that apply to the host not covered by the modular transmitter grant of certification. If the grantee markets their product as being Part 15 Subpart B compliant (when it also contains unintentional- radiator digital circuity), then the grantee shall provide a notice stating that the final host product still requires Part 15 Subpart B compliance testing with the modular transmitter installed.
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and receiver.
  • Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
  • Consult the dealer or an experienced radio/TV technician for help.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:

  • This device may not cause harmful interference.
  • This device must accept any interference received, including interference that may cause undesired operation.

Caution:
Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.
This equipment complies with FCC RF radiation exposure limits set forth for an uncontrolled environment. This device and its antenna must not be co-located or operating in conjunction with any other antenna or transmitter. The antennas used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter.
OEM Integration Instructions
This device is intended only for OEM integrators under the following conditions:

  • The transmitter module may not be co-located with any other transmitter or antenna.
  • The module shall be only used with the external antenna(s) that has been originally tested and certified with this module.

As long as the conditions above are met, further transmitter test will not be required. However, the OEM integrator is still responsible for testing their end-product for any additional compliance requirements required with this module installed (for example, digital device emissions, PC peripheral requirements, etc.).
Validity of Using the Module Certification
In the event that these conditions cannot be met (for example certain laptop configurations or co-location with another transmitter), then the FCC authorization for this module in combination with the host equipment is no longer considered valid and the FCC ID of the module cannot be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC authorization.
End Product Labeling
The final end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC ID: 2AC7Z-ESPS2MINI2”.

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Revision History

Date Version Release notes
2022-09-22 v0.5 Preliminary release

Disclaimer and Copyright Notice
Information in this document, including URL references, is subject to change without notice.
ALL THIRD PARTY’S INFORMATION IN THIS DOCUMENT IS PROVIDED AS IS WITH NO WARRANTIES TO ITS AUTHENTICITY AND ACCURACY.
NO WARRANTY IS PROVIDED TO THIS DOCUMENT FOR ITS MERCHANTABILITY, NON- INFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, NOR DOES ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE.
All liability, including liability for infringement of any proprietary rights, relating to use of information in this document is disclaimed. No licenses express or implied, by estoppel or otherwise, to any intellectual property rights are granted herein.
The Wi-Fi Alliance Member logo is a trademark of the Wi-Fi Alliance. The Bluetooth logo is a registered trademark of Bluetooth SIG.
All trade names, trademarks and registered trademarks mentioned in this document are property of their respective owners, and are hereby acknowledged.
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