esp32sim

What is esp32sim?

esp32sim is an open-source emulator written in Rust that runs real ESP32 firmware locally or in a web browser. It models four ESP32 system-on-chips across Espressif's Xtensa and RISC-V architectures. The emulator boots actual mask ROM, second-stage bootloaders, and unmodified application images without requiring patched code or stubs.

It includes detailed hardware models for peripherals like GPIO, UART, timers, SPI flash, and camera interfaces. A built-in virtual Wi-Fi access point handles WPA2 authentication, DHCP, DNS, and NTP, allowing networked applications to function. Display drivers for screens like ST7735 and ST7789 are also supported.

The project provides command-line tools for desktop use and compiles to WebAssembly for browser execution. It operates entirely offline with no accounts, cloud dependencies, or subscriptions. The classic ESP32 version is considered mature, while support for the C3 and C6 variants is currently in development.

esp32sim features

• Boots real ESP32 ROM, bootloader, and unmodified firmware
• Models Xtensa and RISC-V CPU architectures with JIT acceleration
• Includes virtual Wi-Fi with WPA2, DHCP, DNS, and NAT support
• Runs natively on desktop or in the browser via WebAssembly
• Supports multiple display drivers and peripheral hardware models
• Operates completely offline with no accounts or cloud services

Who uses esp32sim and for what

• Test embedded firmware updates without needing physical ESP32 boards
• Debug boot sequences and ROM initialization on different chip variants
• Verify Wi-Fi connectivity and network stack behavior in isolated environments
• Run automated integration tests for FreeRTOS applications on CI servers
• Prototype display and sensor code before committing to hardware design

esp32sim FAQ

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