The newer model, C3, C6, C5 all have RSIC-V cores which make it a dream to run Rust (basically: rustup target add riscv32imac-unknown-none-elf).

Here is a good introduction: https://kerkour.com/introduction-to-embedded-development-wit...

[1]: https://tingouw.com/blog/cloud_notes/badwater_intro#day-5-8m...

Anecdote about this summary at the bottom: > This setup gives you the best of both worlds: ESP-IDF and FreeRTOS manage Wi-Fi, BLE, and system tasks on Core 0, while Core 1 runs your bare-metal Rust code at full speed with zero scheduler interference.

I am doing something somewhat like this, but with separate MCUs instead of separate cores. I flashed Esp-Hosted-MCU onto an ESP-32 (C3, but any including S3 will work). This is official firmware which turns the ESP into a "radio co-processor", so you can treat it like a SPI or UART Wi-Fi/BLE chip.

On another MCU (STM32), I run bare-metal firmware in rust which talks to the radio over SPI. Wi-Fi uses the ESP IDF, and BLE uses standard HCI commands.