ESP32-S31 Function CoreBoard-1 Adds Gigabit IoT I/O

ESP32-S31 Function CoreBoard-1 gives developers a ready-made route into Espressif’s new ESP32-S31 family, with the new user guide now documenting a board built around the ESP32-S31-WROOM-3 module. For Elektor readers who have followed Espressif’s CES 2026 direction, this is the practical follow-up: a board with Wi-Fi 6, Bluetooth Classic, Bluetooth LE, IEEE 802.15.4, Gigabit Ethernet, USB OTG, and audio hardware on one PCB.

Inside the ESP32-S31 Function CoreBoard-1

The board is based on the ESP32-S31-WROOM-3 module, which brings the ESP32-S31 SoC into a more accessible development format. Espressif’s documentation describes the module as suitable for Wi-Fi, Bluetooth, Zigbee, Thread, and Matter-related IoT work, and the board makes that broader feature set easier to evaluate without first building a custom baseboard.
 

The wired side is unusually strong for an ESP32-class development board. There is an RJ45 Ethernet port with 10/100/1000 Mbps auto-negotiation, a USB 2.0 Type-A OTG port for host applications, and two USB Type-C ports: one for USB Serial/JTAG and one via the onboard USB-to-UART bridge. The Type-A host port can supply up to 500 mA, which is useful for quick peripheral tests without immediately reaching for a second powered hub.

Espressif has also put useful audio hardware on the board. The ES8311 mono audio codec connects over I2S and I²C, while an onboard NS4150B Class-D amplifier can drive a 4 Ω, 3 W speaker. There is also an onboard microphone, speaker connector, reset and boot buttons, and an addressable RGB LED driven by GPIO60. In other words, the board is not only a radio test platform; it can be used for voice, alerting, simple smart-speaker, and connected audio experiments.

ESP32-S31 Function CoreBoard-1 Applications

The ESP32-S31 itself is a dual-core, 32-bit RISC-V part running up to 320 MHz, with Espressif positioning it for more demanding IoT and HMI-style applications. The company’s launch material highlights MMU support, 60 GPIOs, 512 KB SRAM, and support for high-speed external PSRAM. That makes the S31 feel less like a bare connectivity MCU and more like a controller for devices that need networking, user interaction, and peripheral bandwidth in the same design.

The most obvious use cases are gateways, compact HMI panels, smart-home bridges, audio-enabled control nodes, and industrial or lab devices that need both wired and wireless connectivity. The combination of Wi-Fi 6, Bluetooth 5.4, IEEE 802.15.4, and Gigabit Ethernet also makes the board useful for engineers comparing network paths rather than committing to one radio or one physical layer too early. This is often where development boards earn their keep: not in the glorious final product, but in the messy middle where every interface decision still wants to pick a fight.

Getting Started with the Board

For development, Espressif points users toward ESP-IDF, its standard framework for ESP32-family devices. The board can be powered through either USB Type-C port, and the documentation notes that Windows, Linux, and macOS should generally recognize the board automatically when connected. For current measurements, the J5 header can be used to isolate the ESP32-S31-WROOM-3 module’s current draw from the rest of the board, which is useful when moving from “it works” to “it works without eating the battery like a raccoon in a bin.”

Espressif’s latest technical-document index lists the ESP32-S31 Function CoreBoard-1 user guide, ESP32-S31-WROOM-3 datasheet, and ESP32-S31 chip datasheet as updated on May 21, 2026. That matters because the board now has enough public documentation to be more than a slide-deck curiosity: developers can start checking pinout, power, Ethernet, USB, audio, and measurement details against real design work.