ESP32-S31-Function-CoreBoard-1
Overview
The ESP32-S31-Function-CoreBoard-1 is a development board based on the ESP32-S31-WROOM-3 module with Wi-Fi, Bluetooth Classic, Bluetooth LE, and IEEE 802.15.4. It integrates Gigabit Ethernet, USB 2.0 OTG, and onboard audio peripherals for connected IoT applications.
Development board appearance and core components
ESP32-S31-Function-CoreBoard-1 - front (click to enlarge)
ESP32-S31-Function-CoreBoard-1 - back (click to enlarge)
Description of Components
The following table lists the key components on the front and back of the board in clockwise order.
| No. | Key Component | Description |
|---|---|---|
| 1 | J2 | All available GPIO pins are broken out to header J2 for easy interfacing. For more details, see Header Block. |
| 2 | RJ45 Ethernet Port | An Ethernet port supporting 10/100/1000 Mbps auto-negotiation. |
| 3 | Ethernet Transformer | Transformer module for the RJ45 Ethernet port. |
| 4 | USB 2.0 Type-A Port | The USB 2.0 Type-A port is connected to the USB 2.0 OTG High-Speed interface of the ESP32-S31, compliant with the USB 2.0 specification. When communicating with other devices via this port, the ESP32-S31 acts as a USB host, providing up to 500 mA of current. |
| 5 | USB Serial/JTAG Port | USB Type-C port that supports USB 2.0 Full-Speed data rate. It can be used to supply power to the board, flash firmware to the ESP32-S31 chip, communicate with the chip via the USB protocol, and perform JTAG debugging. |
| 6 | USB Type-C to UART Port | Used for power supply to the board, flashing applications to the chip, as well as communication with the ESP32-S31 chip via the on-board USB-to-UART bridge. |
| 7 | 3.3 V Power-on LED | Turns on when the board is connected to USB power. |
| 8 | J5 | Used for current measurement. See details in section Current Measurement. |
| 9 | 5 V to 3.3 V DC/DC Converter | Power regulator that converts a 5 V supply into a 3.3 V output. |
| 10 | ESP32-S31-WROOM-3 | ESP32-S31-WROOM-3 integrates the ESP32-S31 chip and supports Bluetooth 5.4 (LE) and IEEE 802.15.4 (Zigbee/Thread/Matter), suitable for a wide range of low-power IoT applications. |
| 11 | Microphone | Onboard microphone connected to the interface of the audio codec chip. |
| 12 | RGB LED | Addressable RGB LED, driven by GPIO60. |
| 13 | Audio Codec Chip | ES8311 is a low-power mono audio codec. It includes a single-channel ADC, a single-channel DAC, a low-noise pre-amplifier, a headphone driver, digital sound effects, analog mixing, and gain functions. It interfaces with the ESP32-S31 chip over I2S and I2C buses to provide hardware audio processing independent of the audio application. |
| 14 | Reset Button | Press this button to reset the ESP32-S31. |
| 15 | Speaker Output Port | This port is used to connect a speaker. The maximum output power can drive a 4 Ω, 3 W speaker. The pin spacing is 2.00 mm. |
| 16 | Boot Button | Download button. Holding down Boot and then pressing Reset initiates Firmware Download mode for downloading firmware through the UART port or USB Serial/JTAG port. |
| 17 | Audio PA Chip | NS4150B is an EMI-compliant, 3 W mono Class D audio power amplifier that amplifies audio signals from the audio codec chip to drive speakers. |
| 18 | Ethernet PHY IC | Ethernet PHY chip connected to the ESP32-S31 RGMII interface and the RJ45 Ethernet port. |
| 19 | USB-to-UART Bridge | Single-chip USB-to-UART bridge that works with the USB Type-C to UART Port for board power, firmware flashing, and serial communication with the ESP32-S31 chip. |
| 20 | Switch | TPS2051C is a USB power switch that provides a 500 mA output current limit. |
Hardware Reference – Pin Map (J2)
| No. | Name | Type [1] | Function |
|---|---|---|---|
| 1 | G | G | Ground |
| 2 | G | G | Ground |
| 3 | TX0 | I/O/T | U0TXD, GPIO58 |
| 4 | RXD | I/O/T | U0RXD, GPIO59 |
| 5 | 61 | I/O/T | BOOT, GPIO61 |
| 6 | 60 | I/O/T | GPIO60 [2] |
| 7 | 2 | I/O/T | GPIO23 |
| 8 | G | G | Ground |
| 9 | 0 | I/O/T | GPIO0 |
| 10 | 3 | I/O/T | GPIO3 |
| 11 | 49 | I/O/T | GPIO49 |
| 12 | 1 | I/O/T | GPIO1 |
| 13 | 47 | I/O/T | GPIO47 |
| 14 | 48 | I/O/T | GPIO48 |
| 15 | 45 | I/O/T | GPIO45 |
| 16 | 46 | I/O/T | GPIO46 |
| 17 | 43 | I/O/T | GPIO43 |
| 18 | 44 | I/O/T | GPIO44 |
| 19 | 40 | I/O/T | GPIO40 |
| 20 | 42 | I/O/T | GPIO42 |
| 21 | 39 | I/O/T | GPIO39 |
| 22 | 38 | I/O/T | GPIO38 |
| 23 | 37 | I/O/T | GPIO37 |
| 24 | 36 | I/O/T | GPIO36 |
| 25 | 35 | I/O/T | GPIO35 |
| 26 | D0 | I/O/T | SDIO_DATA0, GPIO20 |
| 27 | D1 | I/O/T | SDIO_DATA1, GPIO21 |
| 28 | D2 | I/O/T | SDIO_DATA2, GPIO22 |
| 29 | D3 | I/O/T | SDIO_DATA3, GPIO23 |
| 30 | CLK | I/O/T | SDIO_CLK, GPIO24 |
| 31 | CMD | I/O/T | SDIO_CMD, GPIO25 |
| 32 | 4 | I/O/T | GPIO4 |
| 33 | G | G | Ground |
| 34 | G | G | Ground |
| 35 | 3V3 | P | 3.3 V power supply |
| 36 | 3V3 | P | 3.3 V power supply |
| 37 | G | G | Ground |
| 38 | G | G | Ground |
| 39 | 5V | P | 5 V power supply |
| 40 | 5V | P | 5 V power supply |
[1] P: Power; I: Input; O: Output; T: High-impedance; G: Ground.
[2] Used to drive the addressable RGB LED (GPIO60).
Start Application Development
Before powering up your ESP32-S31-Function-CoreBoard-1, make sure that it is in good condition with no obvious sign of damage.
Required Hardware
- ESP32-S31-Function-CoreBoard-1
- USB 2.0 cable (USB-A to Type-C)
- Computer running Windows, Linux, or macOS
[!NOTE] Be sure to use a good quality USB cable. Some cables are for charging only and do not provide the needed data lines and will not work for programming this board.
Hardware Setup
Connect the ESP32-S31-Function-CoreBoard-1 to your computer using a USB cable. The board can be powered through any of the USB Type-C ports.
- Via the USB-to-UART port or the ESP32-S31 USB port (either port or both), default method (recommended)
- 5V and G (GND) pin headers
Current Measurement
The J5 headers on ESP32-S31-Function-CoreBoard-1 (see J5 in Figure ESP32-S31-Function-CoreBoard-1 - front (click to enlarge)) can be used for measuring the current drawn by the ESP32-S31-WROOM-3 module:
- Remove the jumper: Power supply between the module and peripherals on the board is cut off. To measure the module's current, connect an ammeter in series via the J5 headers.
- Apply the jumper (factory default): Restore the board's normal functionality.
Software Setup
Proceed to ESP-IDF Get Started to set up the development environment and flash an application to your board.
[!NOTE] The board communicates with the host over USB. Most operating systems (Windows, Linux, macOS) include the required drivers, and the board is recognized automatically once connected. If the device is not recognized or the serial port cannot be opened, see Establish Serial Connection with ESP32-S31.
Espressif provides the esp_board_manager component for many development boards to simplify initialization of onboard peripherals such as LCD, audio codec, buttons, and LEDs. See the esp_board_manager component in the ESP Component Registry for supported boards.
Other Development Framework Options
In addition to ESP-IDF, this board supports the following frameworks and options for different user needs:
- ESP-AT: Control the board over UART using AT commands without writing embedded application code.
- Espressif Bluetooth LE ecosystem: Develop Bluetooth LE applications using solutions such as ESP-BLE-MESH and ESP-BLE-AUDIO to accelerate time-to-market and mass production.
- ESP-GMF: Espressif general multimedia framework with audio/video processing components for multimedia applications.
- Wi-Fi audio/video examples: Sample Wi-Fi audio and video applications to help integrate multimedia features into your project.
- Bluetooth audio: Unified Bluetooth audio APIs supporting Bluetooth Classic and LE Audio.
- ESP-Matter: Build Matter and Thread devices suited to low-power and battery-powered scenarios.
Contents and Packaging
This development board is available in several models. See the ESP Product Selector, open the Development Board tab, and browse the available models.
- For retail orders, go to Get Samples.
- For wholesale orders, go to Contact Us.
Related Documents
Download the following documents from the ESP32-S31-Function-CoreBoard-1 user guide:
- ESP32-S31-Function-CoreBoard-1 schematic (PDF)
- ESP32-S31-Function-CoreBoard-1 PCB layout (PDF)
- ESP32-S31-Function-CoreBoard-1 dimensions (PDF)
- ESP32-S31-Function-CoreBoard-1 dimensions source file (DXF) - You can view it with Autodesk Viewer online