Firmware

Flashing Pre-built Firmware

Pre-built firmware binaries are published with each GitHub release. Download the latest .bin file from there.

Flashing with espflash

Install espflash:

cargo install espflash --locked

Then flash the downloaded binary:

espflash flash --chip esp32s3 esp-butt.bin

Building from Source

Prerequisites

Install the Espressif toolchain:

cargo install espup --locked
espup -t esp32s3 -s --toolchain-version 1.93.0.0

The toolchain uses the esp channel (Espressif's Xtensa fork). Target triple: xtensa-esp32s3-espidf.

Build and Flash

Switch the build target to xtensa-esp32s3-espidf in .cargo/config.toml (and .vscode/settings.json for rust-analyzer):

cargo build          # debug build
cargo run            # build, flash, and open serial monitor

cargo run flashes via espflash flash --monitor as configured in .cargo/config.toml.

Desktop Mock (no device needed)

Switch the target to x86_64-unknown-linux-gnu:

cargo run

Requires the kitty terminal emulator. The display output renders in a separate kitty window. Use mouse to interact with sliders and keyboard arrows + Enter to simulate button presses.

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Architecture

• src/app/ — platform-independent state machine and UI screens
• src/ble/ — NimBLE BLE scanning and GATT client (ESP only)
• src/buttplug/ — Buttplug server/client, device config, deferred connection approval
• src/hw/ — display (I2C OLED), encoder, sliders, ticker; split into hw/esp/ and hw/mock/
• src/utils/ — FreeRTOS task spawning, PSRAM heap, logging

CPU affinity: BLE on Core 0, app logic on Core 1.