picofuse

Requirements

• The third_party/pico-sdk submodule, initialized recursively (pico-sdk itself pulls in further submodules — tinyusb, btstack, cyw43-driver, lwip, mbedtls):

  git submodule update --init --recursive

• An ARM GNU Toolchain (arm-none-eabi-gcc and friends) on PATH.

• CMake 3.20+.

• Python 3 (used by pico-sdk's own build for code generation and picotool).

Purpose

This repository builds a standalone, per-board "picofuse" installation — a compiled libpicosdk.a (plus the picofuse/sys runtime layer) together with its headers and pkg-config metadata, installed under a plain directory prefix (e.g. /opt/picofuse/<board>). A third party who only has that installed prefix — not this repository, not the pico-sdk source tree — can build a real .elf for that board using nothing but pkg-config and the ARM GNU toolchain:

export PKG_CONFIG_PATH=/opt/picofuse/<board>/lib/pkgconfig
arm-none-eabi-gcc $(pkg-config --cflags picosdk) -c app.c -o app.o
arm-none-eabi-gcc app.o $(pkg-config --libs picosdk) -o app.elf

Building and installing a library for each board

Define PICO_BOARD for the target board/chip combination.

# Pico (RP2040)
cmake -S . -B build-pico -DPICO_BOARD=pico
cmake --build build-pico --target picosdk_static picofuse_sys_pico_static
cmake --install build-pico --prefix /opt/picofuse/pico

# Pico W (RP2040 + CYW43 Wi-Fi/Bluetooth)
cmake -S . -B build-pico_w -DPICO_BOARD=pico_w
cmake --build build-pico_w --target picosdk_static picofuse_sys_pico_static
cmake --install build-pico_w --prefix /opt/picofuse/pico_w

# Pico 2 (RP2350)
cmake -S . -B build-pico2 -DPICO_BOARD=pico2
cmake --build build-pico2 --target picosdk_static picofuse_sys_pico_static
cmake --install build-pico2 --prefix /opt/picofuse/pico2

# Pico 2 W (RP2350 + CYW43)
cmake -S . -B build-pico2_w -DPICO_BOARD=pico2_w
cmake --build build-pico2_w --target picosdk_static picofuse_sys_pico_static
cmake --install build-pico2_w --prefix /opt/picofuse/pico2_w

Installing produces, under each prefix:

• lib/libpicosdk.a, lib/libpicofuse_sys_pico.a
• include/ — every SDK module's headers merged into one consolidated tree, plus picofuse/ and runtime/
• lib/pkgconfig/picosdk.pc, lib/pkgconfig/picofuse_sys_pico.pc (the latter Requires: picosdk, so pulling it in via pkg-config also pulls in picosdk's own flags)
• lib/picosdk/src/ — the linker script fragments the .pc file's Libs point at