ESPRESSIF ESP32-MINI-2U Wi-Fi Module User Manual

ESP32-S2-MINI-2U
User Manual

ESP32-MINI-2U Wi-Fi Module

2.4 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-croprocessor
4 MB flash and optional 2 MB PSRAM in chip package
37 GPIOs, rich set of peripherals
External antenna connector ESP32-S2-MINI-2U

Module Overview

ESP32-S2-MINI-2U 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.
Table 1: ESP32-S2-MINI-2U Specifications

Camera interface, ADC, DAC, touch sensor, temperature sensor, USB OTG
Integrated crystal| 40 MHz crystal
Operating voltage/Power supply| 3.0 V iv 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

2.1 Pin Layout
The pin diagram below shows the approximate location of pins on the module.

2.2 Pin Description
The module has 65 pins. See pin definitions in Table 2.
For peripheral pin configurations, please refer to ESP32-S2 Series Datasheet.

Table 2: Pin Definitions

Low: off, the chip powers off.
Note: Do not leave the EN pin floating.

1 P: power supply; I: input; O: output; T: high impedance.
21026 is used by the embedded PSRAM on the ESP32-S2-MINI-2U-N4R2 module, and cannot be used for other purposes.

Get Started

3.1 What You Need
To develop applications for module you need:

• 1 x ESP32-82-MINI-2U
• 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.

3.2 Hardware Connection

1. Solder the ESP32-S2-MINI-2U module to the RF testing board as shown in Figure 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 |00 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 100 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:
100 is internally logic high.
If 100 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-2U, please refer to ESP32-S2 Series Datashest.

3.3 Set up Development Environment
The Espressif loT 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.
3.3.1 Install Prerequisites
To compile with ESP-IDF you need to get the following packages:

• CentOS 7 & 8: sudo yum -y update & sudo yum install git wget flex bison gperf python3 python3- pip 2 1 python3-setuptools cmake ninja-build ccache dfu-util libusbx
• Ubuntu and Debian: sudo apt-get install git wget flex bison gperf python3 python3-pip python3- setuptools 2 1 cmake ninja-build ccache libffi-dev libssl-dev dfu-util libusb-1.0-0
• Arch: sudo pacman -S ——needed gcc git make flex bison gperf python-pip cmake ninja ccache 2 1 dfu-util libusb

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.

3.3.2 Get ESP-IDF
To build applications for ESP32-S2-MINI-2U 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’:
+ mkdir -p ~/esp
2 cd ~/esp
s git clone —-recursive https://github.com/espressif/esp-idf.git
ESP-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.

3.3.3 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.
1 cd ~/esp/esp-idf
2 ./install.sh

3.3.4 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: i« $HOME/esp/esp- idf/export.sh
Now everything is ready, you can build your first project on ESP32-S2-MINI-2U module.

3.4 Create Your First Project
3.4.1 Start a Project
Now you are ready to prepare your application for ESP32-S2-MINI-2U module. You can start with get-started/hello_world project from examples directory in ESP- IDF.
Copy get-started/hello_world to ~/esp directory:
+ cd ~/esp
2 cp —r $IDF_PATH/examples/get-started/hello_world.
There 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.
3.4.2 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: i s /dev/ttyx

Note:
Keep the port name handy as you will need it in the next steps.

3.4.3 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’.
+ cd ~/esp/hello_world
2 idf.py set-target esp32s2 2 idf.py menuconfig
Setting 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:

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_word”. 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.
3.4.4 Build the Project
Build the project by running: + idf.py build
This command will compile the application and all ESP-IDF components, then it will generate the bootloader, partition table, and application binaries..
$ idf.py build
2 Running cmake in directory /path/to/hello_world/build
2 Executing “cmake -G Ninja —warn-uninitialized /path/to/hello_world”…
+ Warn about uninitialized values.
s —— Found Git: /usr/bin/git (found version “2.17.0”)
s —— Building empty aws_iot component due to configuration
7 —— Component names: …
s —— Component paths: …
w0 «us (more lines of build system output)
w2 [527/527] Generating hello_world.bin. esptool.py v2.3.1
s Project build complete. To flash, run this command:
w6 +a/+s/../components/esptool_py/esptool/esptool.py —p (PORT) —b 921600
7 write_flash ——flash_mode dio ——flash_size detect ——flash_freq 40m
12 0x10000 build/hello_world.bin build 0x1000 build/bootloader/bootloader.bin 0x8000
s build/partition_table/partition-table.bin
20 or run ‘idf.py —p PORT flash’
If there are no errors, the build will finish by generating the firmware binary .bin file.
3.4.5 Flash onto the Device
Flash the binaries that you just built onto your module by running:
+ idf.py —-p PORT [-b BAUD] flash
Replace 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:
– – 2 esptool.py esp32s2 -p /dev/ttyUSBO —b 460800 —before=default_reset ——after=hard_reset
2 write_flash ——flash_mode dio ——flash_freq 80m ——flash_size 4 MB @x@ bootloader/bootloader.
bin
4+ ©0x10000 hello_world.bin 0x8000 partition_table/partition-table.bin
s esptool.py v3.2-dev
s Serial port /dev/ttyUSBe
; Connecting….
= Chip is ESP32-S2
s Features: WiFi
o Crystal is 40MHz
i1 MAC: 7c:df:al:e0:00:64
2 Uploading stub…
w2 Running stub…
« Stub running…
s Changing baud rate to 460800
s Changed.
«7 Configuring flash size…
52 Flash will be erased from 0x00000000 to 0x00004fff…
5o Flash will be erased from 0x00010000 to 0x00039fff…
20 Flash will be erased from 0x00008000 to 0x00008fff…
21 Compressed 18896 bytes to 11758…
2 Writing at 0x00000000… (100 %)
2 Wrote 18896 bytes (11758 compressed) at 0x00000000 in 0.5 seconds (effective 279.9 kbit/s)
2 Hash of data verified.
25 Compressed 168208 bytes to 88178…
2 Writing at 0x00010000… (16 %)
2 Writing at 0x0001a80f… (33 %)
2 Writing at 0x000201f1… (50 %)
2 Writing at 0x00025dcf… (66 %)
Writing at 0x@002d@be… (83 %)
Writing at @x@0036c07… (100 %)
Wrote 168208 bytes (88178 compressed) at 0x@0010000 in 2.4 seconds (effective 569.2 kbit/s
Yeuu
Hash of data verified.
Compressed 3072 bytes to 103…
Writing at @x00008000… (100 %)
s Wrote 3072 bytes (103 compressed) at 0x00008000 in 0.1 seconds (effective 478.9 kbit/s)…
a7 Hash of data verified.
Leaving…
w0 Hard resetting via RTS pin…
+ Done
If there are no issues by the end of the flash process, the board will reboot and start up the “hello_world” application.
3.4.6 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:

• $ idf.py —p /dev/ttyuUSB@ monitor
  2 Running idf_monitor in directory […1/esp/hello_world/build
  2 Executing “python […]/esp-idf/tools/idf_monitor.py -b 115200
  4+ […1/esp/hello_world/build/hello-world.elf”
  s ——— idf_monitor on /dev/ttyUSBe 115200 ——
  s ——— Quit: Ctrl+] | Menu: Ctrl+T
  | Help: Ctrl+T followed by Ctrl+H ——

  ets Jun
  8 2016 00:22:57
  s rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
  o ets Jun
  8 2016 00:22:57
  After startup and diagnostic logs scroll up, you should see “Hello world!” printed out by the application.
  1 O
  2 Hello world!
  2 Restarting in 10 seconds…
  + This is esp32s2 chip with 1 CPU core, WiFi,
  s silicon revision 1
  s Minimum free heap size: 390684 bytes
  + Restarting in 9 seconds…
  s Restarting in 8 seconds
  s Restarting in 7 seconds…
  To exit IDF monitor use the shortcut Ctrl+].
  That’s all what you need to get started with ESP32-S2-MINI-2U 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 vO1. Below are integration instructions for host product manufacturers according to the KDB 996369 D03 OEM Manual vO1.
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: External antenna connector

• Gain: 2.33 dBi Max
  The module can be used for loT applications with a maximum 2.33 dBi antenna. The host manufacturer installing this module into their product must ensure that the final composit 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:
  e Type: External antenna connector

• Gain: 2.33 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-ESPS2MINI2U” 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-ESPS2MINI2U”.

Related Documentation and Resources

Related Documentation

• ESP32-S2 Series Datasheet — Specifications of the ESP32-S2 hardware.

• ESP32-S2 Technical Reference Manual — Detailed information on how to use the ESP32-S2 memory and peripherals.

• ESP32-S2 Hardware Design Guidelines — Guidelines on how to integrate the ESP32-S2 into your hardware product.
  ESP32-S2 Series SoC Errata — Descriptions of errors in ESP32-S2 series of SoCs from chip revision 0 forward.

• Certificates
  https://espressif.com/en/support/documents/certificates

• ESP32-S2 Product/Process Change Notifications (PCN)
  https://espressif.com/en/support/documents/pcns

• ESP32-S2 Advisories — Information on security, bugs, compatibility, component reliability.
  https://espressif.com/en/support/documents/advisories

• Documentation Updates and Update Notification Subscription
  https://espressif.com/en/support/download/documents

Developer Zone

• ESP-IDF Programming Guide for ESP32-S2 — Extensive documentation for the ESP-IDF development framework.

• £SP-IDF and other development frameworks on GitHub.
  https://github.com/espressif

• ESP32 BBS Forum — Engineer-to-Engineer (E2E) Community for Espressif products where you can post questions, share knowledge, explore ideas, and help solve problems with fellow engineers.
  https://esp32.com/

• The ESP Journal — Best Practices, Articles, and Notes from Espressif folks.
  https://blog.espressif.com/

• See the tabs SDKs and Demos, Apps, Tools, AT Frmware.
  https://espressif.com/en/support/download/sdks-demos

Products

• £SP32-S2 Series SoCs — Browse through all ESP32-S2 SoCs.
  https://espressif.com/en/products/socs?id=ESP32-S2

• ESP32-S2 Series Modules — Browse through all ESP32-S2-based modules.
  https://espressif.com/en/products/modules?id=ESP32-S2

• ESP32-S2 Series DevKits — Browse through all ESP32-S2-based devkits.
  https://espressif.com/en/products/devkits?id=ESP32-S2

• ESP Product Selector — Find an Espressif hardware product suitable for your needs by comparing or applying filters.
  https://products.espressif.com/#/product-selector?language=en

Contact Us

• See the tabs Sales Questions, Technical Enquiries, Circuit Schematic & PCB Design Review, Get Samples (Online stores), Become Our Supplier, Comments & Suggestions.
  https://espressif.com/en/contact-us/sales-questions

Revision History

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 TS MERCHANTABILITY, NON INFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, NOR DOES ANY WARRANTY OTHERWISE ARISING OUT OF ANY  PROPOSAL, SPECIFICATION OR SAMPLE.
Al 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.
Al trade names, trademarks and registered trademarks mentioned in this document are property of their respective owners, and are hereby acknowledged.
Copyright © 2022 Espressif Systems (Shanghai) Co., Ltd. All rights reserved.

References

• Get Started - ESP32-S2 - — ESP-IDF Programming Guide latest documentation
• Wireless SoCs, Software, Cloud and AIoT Solutions | Espressif Systems
• Build System - ESP32-S2 - — ESP-IDF Programming Guide latest documentation
• Build System - ESP32-S2 - — ESP-IDF Programming Guide latest documentation
• Get Started - ESP32-S2 - — ESP-IDF Programming Guide latest documentation
• ESP-IDF Versions - ESP32-S2 - — ESP-IDF Programming Guide latest documentation
• ESP32 Forum - Index page
• ESP DevKits | Espressif Systems
• ESP Modules | Espressif Systems
• ESP SoCs | Espressif Systems
• Certificates | Espressif Systems
• Espressif Systems · GitHub
• GitHub - espressif/esp-idf: Espressif IoT Development Framework. Official development framework for Espressif SoCs.
• esp-idf/examples/get-started/hello_world at c77c4ccf6c43ab09fd89e7c907bf5cf2a3499e3b · espressif/esp-idf · GitHub
• esp-idf/examples at master · espressif/esp-idf · GitHub
• ESP Product Selector

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