Espressif's new ESP32-S31 microcontroller features gigabit Ethernet and USB 2.0 host

New ESP32-S31 Features

Espressif introduced the ESP32-S31, a new microcontroller with a feature set typically found in single-board computers. Key additions include a gigabit Ethernet MAC, a USB 2.0 High-Speed host controller, and an SD card interface with two slots. It also incorporates a camera input and a parallel LCD controller.

Enhanced Connectivity and Peripherals

The ESP32-S31 significantly upgrades networking with a 1000 Mbps Ethernet MAC, a substantial increase from the 100 Mbps on the ESP32-P4. It uses an 8P8C connector and an RGMII interface for gigabit speeds. The USB 2.0 High-Speed OTG controller provides a full-size Type-A socket capable of supplying 500 mA in host mode. Additional peripherals include two I2S controllers, fourteen capacitive touch channels, a CAN FD controller, and four MCPWM units.

CPU and Memory Architecture

The S31 is powered by two 32-bit RISC-V cores, each running at up to 320 MHz with a floating-point unit. One core includes a 128-bit SIMD data path, and there is also a separate 40 MHz low-power core. Each core has 32KB of L1 instruction cache, and they share 64KB of data cache. The device supports up to 64 MB of PSRAM over a 250 MHz 8-bit DDR interface and up to 256 MB of flash memory, a notable improvement over previous ESP32 models where the PSRAM interface was shared with flash.

Integration of a Memory Management Unit

A significant architectural change in the ESP32-S31 is the inclusion of a real Memory Management Unit (MMU). This feature is crucial for running operating systems like Linux, further positioning the S31 closer to single-board computers in terms of capability and application potential.