ESP32-S31 Microcontroller : Architecture, Working, Differences & Its Applications

The ESP32-S31 is a new-generation microcontroller from Espressif Systems, developed to address the growing demands of modern embedded systems and connected applications. As IoT devices become increasingly complex, developers need platforms that can handle more demanding processing tasks while maintaining flexibility, efficiency and reliable operation. The ESP32-S31 is designed to meet these requirements, offering a foundation for building a wide range of advanced electronic products.

Positioned as a successor in Espressif’s ESP32 family, the ESP32-S31 brings a different approach to processing and system design. Its architecture is intended to support applications that go beyond basic sensor monitoring and device connectivity, including products that require more sophisticated computing, multimedia handling and real-time operation.

In this article, we take a closer look at the ESP32-S31, exploring what it is, how it works, its internal architecture and technical specifications. We also examine its advantages and limitations, compare it with other ESP32 family devices, and discuss the applications and design considerations that developers should understand before choosing it for an embedded or IoT project.

Espressif Systems announced the ESP32-S31 microcontroller in March 2026. It works as a major upgrade to the popular ESP32-S3 line by changing from the earlier Xtensa architecture to a current RISC-V core. This microcontroller is designed for advanced IoT applications that require complete connectivity and rich HMI (human-machine interfaces). This article elaborates on the ESP32-S31 microcontroller, its working, and its applications.

What is the ESP32-S31 Microcontroller?

The ESP32-S31 is a high-performance dual-core 32-bit RISC-V system-on-chip (SoC) with up to 320 MHz clock speed. This microcontroller is designed to support machine learning and edge AI tasks like advanced signal processing, neural network inference, smart audio, and computer vision applications. This chip delivers 60 GPIOs and shows adaptability in complex designs that support different wireless protocols, peripherals, and display interfaces.

How does the ESP32-S31 Microcontroller Work?

The ESP32-S31 is a high-performance, multi-protocol System-on-Chip (SoC) developed by Espressif Systems for advanced Internet of Things, multimedia, and edge AI applications. It operates by combining a dual-core 32-bit RISC-V high-performance processor, a dedicated low-power RISC-V processor, integrated wireless connectivity, memory controllers, and hardware acceleration peripherals within a single chip.

The two high-performance CPU cores operate at clock speeds of up to 320 MHz and execute application instructions, process sensor data, manage communication protocols, and handle complex computing operations. One of these cores features a 128-bit data path with SIMD (Single Instruction, Multiple Data) instructions, enabling parallel processing of multiple data elements for computationally intensive workloads such as signal processing and neural network inference.

In addition to the high-performance processor, the ESP32-S31 integrates a single-core low-power RISC-V processor operating at up to 40 MHz. This processor handles suitable low-power operations, reducing the need to keep the high-performance cores active continuously.

The SoC also incorporates 512 KB of internal SRAM, 320 KB of ROM, and 32 KB of low-power SRAM. It supports external flash and high-speed PSRAM interfaces, allowing applications to access additional memory for storing firmware, image data, audio buffers, and other application resources.

For wireless communication, the ESP32-S31 integrates 2.4 GHz Wi-Fi 6, Bluetooth 5.4 Low Energy (LE), Bluetooth Classic, and IEEE 802.15.4 connectivity. These interfaces enable communication using Wi-Fi, Bluetooth, Zigbee 3.0, and Thread 1.4 protocols. It also includes a Gigabit Ethernet MAC for wired networking applications when connected to an appropriate external Ethernet PHY.

Furthermore, dedicated hardware peripherals such as the JPEG codec, Pixel-Processing Accelerator (PPA), 2D-DMA controller, LCD and camera controller, and audio processing interfaces support multimedia operations. These hardware resources reduce the processing workload on the CPU and enable applications involving camera input, image processing, display control, and intelligent audio.

Thus, the ESP32-S31 combines processing, memory, connectivity, and hardware acceleration capabilities to support advanced IoT devices, smart home systems, multimedia products, and edge AI applications.

Specifications

The key specifications of the ESP32-S31 microcontroller are listed below.

Features	ESP32-S31 Specifications
Manufacturer	Espressif Systems
Processor architecture	32-bit RISC-V
High-performance CPU	Dual-core processor
Maximum CPU frequency	Up to 320 MHz
Low-power processor	Single-core RISC-V
Low-power CPU frequency	Up to 40 MHz
Internal ROM	320 KB
Internal SRAM	512 KB
Low-power SRAM	32 KB
External memory	Supports external flash and PSRAM
PSRAM interface	Up to 250 MHz, 8-bit DDR
Wi-Fi	2.4 GHz Wi-Fi 6 (802.11ax)
Bluetooth	Bluetooth 5.4 LE and Bluetooth Classic
IEEE 802.15.4	Zigbee 3.0 and Thread 1.4
Ethernet	Integrated 1000 Mbps Ethernet MAC
USB	USB 2.0 High-Speed OTG (up to 480 Mbps)
CAN	CAN FD controller
GPIO	Up to 60 programmable GPIOs
Camera interface	DVP camera interface
Display interface	Parallel RGB and I8080 interfaces
Image processing	JPEG codec and Pixel-Processing Accelerator (PPA)
Audio interface	I2S
Security	Secure Boot and hardware cryptographic accelerators
Package	QFN80 (8 × 8 mm)

Important Features of the ESP32-S31

The ESP32-S31 specifications make it suitable for applications requiring high processing performance, multi-protocol connectivity, advanced display interfaces, and multimedia processing. Actual available features depend on the selected chip or module configuration and hardware design.

ESP32-S31 Microcontroller Architecture

The ESP32-S31 is a high-performance, multi-protocol wireless System-on-Chip (SoC) developed by Espressif Systems. Its architecture is based on a dual-core 32-bit RISC-V high-performance processor, supported by a separate low-power RISC-V processor. It integrates memory controllers, wireless communication interfaces, security mechanisms, and dedicated hardware accelerators to support advanced IoT, edge AI, and human-machine interface (HMI) applications.

The architecture is designed to handle multiple operations simultaneously, including application execution, wireless communication, image processing, audio processing, and peripheral management. It also provides up to 60 programmable GPIO pins, allowing developers to connect various external sensors, displays, cameras, and other electronic components.

Architecture Components

The ESP32-S31 architecture consists of several major functional blocks that work together to provide processing, memory management, connectivity, multimedia processing, and security capabilities.

High-Performance CPU

The ESP32-S31 incorporates a dual-core 32-bit RISC-V high-performance processor operating at up to 320 MHz. It executes application programs, processes sensor information, manages communication tasks, and performs computational operations. One of its cores features a 128-bit data path with SIMD instructions to accelerate parallel data processing.

Low-Power CPU

The microcontroller includes a separate single-core RISC-V low-power processor operating at up to 40 MHz. It handles suitable low-power operations and helps reduce the need to activate the high-performance processor for every task.

Memory Controller

The memory subsystem includes 320 KB ROM, 512 KB internal SRAM, and 32 KB low-power SRAM. It also supports external flash and high-speed PSRAM through dedicated memory interfaces. These resources provide storage and working memory for firmware, application data, image buffers, and other processing requirements.

Wireless Communication Subsystem

The ESP32-S31 integrates multiple wireless communication technologies, including 2.4 GHz Wi-Fi 6, Bluetooth 5.4 LE, Bluetooth Classic, and IEEE 802.15.4. These technologies enable wireless networking and support communication protocols such as Zigbee 3.0 and Thread 1.4.

Ethernet MAC

The architecture includes an integrated 1000 Mbps Ethernet Media Access Controller (MAC) for wired networking. It handles Ethernet data communication and requires an appropriate external PHY and supporting circuitry to establish a physical Ethernet connection.

USB Controller

The ESP32-S31 incorporates a USB 2.0 High-Speed OTG controller that supports USB communication at speeds of up to 480 Mbps. It also includes a USB Serial/JTAG controller for programming, debugging, and serial communication.

Camera and Display Controller

The integrated LCD and Camera Controller (LCD_CAM) provides interfaces for connecting external camera sensors and display modules. It supports DVP camera input and parallel display interfaces, including RGB and I8080, making it suitable for multimedia and HMI applications.

Image Processing Accelerators

The ESP32-S31 integrates a JPEG codec, Pixel-Processing Accelerator (PPA), and 2D-DMA controller. These hardware components accelerate image encoding, decoding, pixel processing, and data transfers, reducing the processing workload on the CPU.

Audio Processing Interfaces

The microcontroller provides I2S interfaces and audio-related hardware capabilities for connecting external microphones, audio codecs, and amplifier circuits. These interfaces support applications such as smart speakers, voice assistants, and interactive audio devices.

Security Subsystem

The architecture includes hardware-based security components such as AES, RSA, ECC, SHA, and HMAC accelerators. It also supports Secure Boot, external memory encryption, secure key management, and random number generation to protect firmware and sensitive application data.

GPIO and Peripheral Interfaces

The ESP32-S31 provides up to 60 programmable GPIO pins and several peripheral interfaces, including UART, SPI, I2C, I2S, ADC, DAC, PWM, and CAN FD. These interfaces allow developers to connect external electronic components and implement different embedded control applications.

Power Management Unit

The integrated Power Management Unit (PMU) manages power-related operations across the SoC. Together with its low-power processor and memory subsystem, it supports power-efficient operation in embedded and battery-powered IoT applications.

These architectural components work together to provide the ESP32-S31 with processing flexibility, multi-protocol connectivity, hardware-accelerated multimedia capabilities, and integrated security for advanced embedded applications.

Flexible interfacing: Up to 60 GPIOs and multiple peripheral interfaces for connecting external hardware components.

Hardware security: Cryptographic accelerators, Secure Boot, memory encryption, and hardware-based key protection.

Wired communication: Integrated Gigabit Ethernet MAC and USB 2.0 High-Speed OTG.

Advanced multimedia: Integrated JPEG codec, PPA, 2D-DMA, and LCD and camera controller.

External memory support: High-speed interfaces for external flash and PSRAM expansion.

Wireless connectivity: Integrated Wi-Fi 6, Bluetooth 5.4 LE, Bluetooth Classic, and IEEE 802.15.4 connectivity.

Low-power processing: Dedicated single-core RISC-V processor operating at up to 40 MHz for suitable low-power operations.

High-performance processing: Dual-core RISC-V CPU operating at up to 320 MHz for advanced embedded computing and edge AI workloads.

ESP32-S31 vs. ESP32-S3

The key differences between the ESP32-S31 and ESP32-S3 are listed below.

Features	ESP32-S31	ESP32-S3
CPU architecture	Dual-core 32-bit RISC-V, up to 320 MHz	Dual-core Xtensa LX7, up to 240 MHz
Wi-Fi	Wi-Fi 6 (802.11ax), 2.4 GHz, 20 MHz-only non-AP mode	Wi-Fi 4 (802.11b/g/n), 2.4 GHz, up to 150 Mbps
Bluetooth	Bluetooth 5.4 LE Audio (BIS/CIS) + Classic BR/EDR	Bluetooth 5 LE
USB	USB 2.0 High-Speed OTG (480 Mbps) + USB-Serial/JTAG	USB OTG Full-Speed (12 Mbps) + USB-Serial/JTAG
CAN	CAN FD	TWAI, CAN 2.0
Programmable GPIO	60	45
Package	QFN80	QFN56
Camera / Display	DVP + multi-format LCD	Parallel LCD (RGB/I8080) + DVP Camera
Performance (CoreMark)	~2,195 CoreMark	~1,330 CoreMark

Why ESP32-S31 Microcontroller Matters?

The ESP32-S31 microcontroller represents a revolutionary development for Espressif, merging high-speed dual-core RISC-V processing, gigabit-class networking, and multi-protocol wireless into a single combined chip designed for smart-home infrastructure and edge AI.

It replaces the Xtensa-based architecture with a dual-core 32-bit RISC-V processor operating at up to 320 MHz, delivering approximately a 65% performance boost over the ESP32-S3

This microcontroller combines Wi-Fi 6 (2.4 GHz), IEEE 802.15.4, and Bluetooth 5.4 (Classic and LE Audio), with compatibility for Zigbee 3.0, Thread 1.4, and Matter smart home standards. It integrates radio support with application-layer protocol support

It features a built-in 10/100/1000 Mbps Ethernet MAC that bridges high-speed wireless and wired networks effortlessly.

This microcontroller is equipped with extended SIMD instructions, an on-board JPEG codec, audio accelerators, and a 2D graphics core. Thus, it handles local ML inference, voice/audio processing, and computer vision very efficiently.

It offers up to 60 programmable GPIO pins, providing greater flexibility for hardware designs, high-speed USB 2.0 OTG, and external flash/PSRAM support. Thus, it is perfect for smart displays, industrial automation hubs, and complex IoT gateways.

Advantages

The advantages of the ESP32-S31 microcontroller include the following.

• Its core clock speed is up to 320 MHz, higher than the ESP32-S3’s 240 MHz.
• It significantly accelerates edge AI workloads, complex digital signal processing, and neural network inference.
• It operates on 2.4 GHz Wi-Fi 6, yielding better transmission efficiency, Target Wake Time for better stability. Wi-Fi 6 features such as Target Wake Time can improve power efficiency in suitable configurations, rather than guaranteeing lower consumption.
• It integrates a 1000 Mbps Ethernet MAC, solving the historical network bottlenecks of previous microcontrollers.
• It features dedicated hardware for JPEG encoding & decoding, decreasing CPU strain in camera streaming.
• This microcontroller supports 8- to 24-bit parallel display buses with native RGB888 output & hardware color-space change.
• It interfaces with high-speed 250 MHz 8-bit DDR PSRAM.

Disadvantages

The disadvantages of the ESP32-S31 microcontroller include the following.

• Many third-party drivers, community libraries, and middleware designed for previous Xtensa-based ESP32 variants need updating or porting to smoothly run on the latest architecture.
• The S31 moves to a 32-bit RISC-V core by launching a learning period and migration effort for accessible legacy codebases.
• Espressif announced mass production and availability on July 27, 2026. Development boards are available, although chip and module supply may still be ramping up.
• The published datasheet lists parallel display interfaces, including RGB and I8080, and does not list MIPI DSI.
• Parallel RGB display performance depends on the supported pixel clock, interface configuration, and display resolution.

Applications

The applications of the ESP32-S31 microcontroller include the following.

• It integrates Bluetooth 5.4 (BLE and Classic), IEEE 802.15.4, and Wi-Fi 6 (802.11ax) compatibility for Zigbee, Matter, and Thread standards.
• It is used for real-time computer vision recognition, intelligent sensor data processing, and on-device neural network inference.
• This microcontroller functions as a dedicated communications coprocessor or central orchestrator for multi-protocol smart home ecosystems.
• It is used in AI voice assistants, interactive multimedia terminals, and smart speakers.
• It is equipped with 2D PPA, hardware JPEG decoding, 2D-DMA, high-speed LCD/touch controller, and DVP camera interface support for high-definition displays.
• It is used in IP cameras, smart appliances, and industrial touch panels.
• This microcontroller allows reliable industrial automation, composite USB device hosting, and factory floor gateways.
• It supports speaker outputs, dual-microphone arrays, class-D/mono audio power amplifiers, and low-power mono audio codecs.

Conclusion:

In summary, the ESP32-S31 represents an important development in Espressif’s ESP32 product family, reflecting the increasing demand for embedded platforms that can support more complex and application-specific requirements. Its introduction gives developers another option when evaluating hardware for the next generation of connected electronic products.

However, selecting a microcontroller involves more than looking at its processing capabilities or the number of integrated peripherals. Factors such as software ecosystem maturity, hardware availability, development effort, long-term product support and overall implementation cost also play an important role in determining whether a platform is suitable for a particular project.

For developers and product designers, the ESP32-S31 is worth considering when planning new embedded and IoT solutions. Evaluating it alongside alternatives such as the ESP32-S3 and ESP32-P4 can help identify the most appropriate platform based on the project’s actual requirements. As Espressif continues to expand its documentation, development resources and ecosystem support, the ESP32-S31 may become an interesting option for a broader range of embedded applications.