Repository Guide

Scope

This is one bare-metal C++ firmware target for the Electrosmith Daisy Patch. Application code is under src/; lib/libDaisy and lib/daisySP are recursive git submodules, not packages owned by this repository.
Root CI only builds the firmware. Tests, formatters, and workflows found below lib/ belong to the vendored submodules; there is no root application test or lint target.

Initialize all nested dependencies after a non-recursive clone with git submodule update --init --recursive.
The build requires the arm-none-eabi-* toolchain on PATH, or its binary directory passed as GCC_PATH=.... CI uses Arm GCC 9-2019-q4.
From a clean checkout, run make lib && make. make lib builds both submodule libraries; subsequent application-only changes normally need only make. Artifacts are build/droplets.{elf,hex,bin}.
make clean removes only the root build/; it does not clean or rebuild either library.
Do not use the README's make deploy: APP_TYPE = BOOT_SRAM, but that target invokes the incompatible OpenOCD program recipe and fails. After building, enter Daisy bootloader mode and run make program-dfu (requires dfu-util); it writes build/droplets.bin at 0x90040000.

src/main.cpp owns startup and dispatch: the foreground loop handles controls, OLED drawing, and non-audio outputs, while the Daisy audio callback calls each active droplet's Process method.
Split mode runs left and right droplets against the same audio buffers. Use the Droplet state helpers and GetChannelMin()/GetChannelMax() plus screen bounds rather than hard-coded full-device ranges, or one side can overwrite the other.
The root Makefile discovers only src/*.cpp and src/*/*.cpp. Sources nested more deeply are silently excluded. Object names are flattened into build/, so C++ source basenames must be unique across those directories.

Run ./create-new-droplet.sh PascalCaseName; the script only copies and substitutes the template and does not register the result.
Complete all registration points: add a MenuState in src/menu_item.h, append its visible item in Menu::Menu in src/menu.cpp, include its header in src/main.h, and add construction in GetDroplet in src/main.cpp.
Implement all three DropletState layouts. Droplet::UpdateState recalculates channel/display bounds, then calls SetControls() and UpdateStateCallback() when switching between full and split modes.