PCAL95555 — CMake Integration Guide

How to consume the PCAL95555 driver in your CMake or ESP-IDF project.

Quick Start (Generic CMake)

Option A — Git Submodule (recommended) 

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# From your project root
git submodule add https://github.com/N3b3x/hf-pcal95555-driver.git external/hf-pcal95555-driver
git submodule update --init --recursive

In your top-level CMakeLists.txt:

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add_subdirectory(external/hf-pcal95555-driver)

add_executable(my_app main.cpp)
target_link_libraries(my_app PRIVATE hf::pcal95555)

The hf::pcal95555 alias target provides the header include paths, C++20 compile feature, and generated version header automatically.

Option B — Cloned / Vendored Copy

Same as above — just point add_subdirectory() at wherever you placed the driver checkout:

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add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/third_party/hf-pcal95555-driver)
target_link_libraries(my_app PRIVATE hf::pcal95555)

Option C — Installed Package (find_package)

If the driver has been installed to a system or prefix path:

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# Install from source
cmake -B build -DCMAKE_INSTALL_PREFIX=/opt/hf-drivers
cmake --build build
cmake --install build

Then in the consuming project:

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find_package(hf_pcal95555 REQUIRED)
target_link_libraries(my_app PRIVATE hf::pcal95555)

CMake will locate the package via hf_pcal95555Config.cmake installed in <prefix>/lib/cmake/hf_pcal95555/.

ESP-IDF Integration

The driver ships with an ESP-IDF component wrapper in examples/esp32/components/hf_pcal95555/.

1. Reference the Component

Option 1 — Symlink or copy the wrapper:

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your-esp-project/
├── CMakeLists.txt
├── main/
│   ├── CMakeLists.txt
│   └── app_main.cpp
└── components/
    └── hf_pcal95555/
        └── CMakeLists.txt      ← copy from driver's examples/esp32/components/

Option 2 — Use EXTRA_COMPONENT_DIRS:

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# In your project-level CMakeLists.txt, before include($ENV{IDF_PATH}/...)
set(EXTRA_COMPONENT_DIRS "${CMAKE_CURRENT_LIST_DIR}/../path/to/hf-pcal95555-driver/examples/esp32/components")

2. Override the Driver Root (if needed)

The component wrapper auto-detects the driver root via a relative path. If your directory layout differs, override it:

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set(HF_PCAL95555_ROOT "/absolute/path/to/hf-pcal95555-driver" CACHE PATH "")

3. Require the Component

In your main/CMakeLists.txt:

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idf_component_register(
    SRCS "app_main.cpp"
    INCLUDE_DIRS "."
    REQUIRES hf_pcal95555 driver
)
target_compile_features(${COMPONENT_LIB} PRIVATE cxx_std_20)

4. Include and Use 

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#include "pcal95555.hpp"
#include "pcal95555_version.h"  // optional — version macros

// Create your platform I2C implementation, then:
pcal95555::PCAL95555<MyI2cBus> driver(&bus, /*a0=*/false, /*a1=*/false, /*a2=*/false);
driver.EnsureInitialized();

PCAL95555-Specific Build Variables

These variables are defined in cmake/hf_pcal95555_build_settings.cmake:

Variable Value
HF_PCAL95555_TARGET_NAME hf_pcal95555
HF_PCAL95555_VERSION Current MAJOR.MINOR.PATCH
HF_PCAL95555_PUBLIC_INCLUDE_DIRS inc/ + generated header dir
HF_PCAL95555_SOURCE_FILES "" (header-only)
HF_PCAL95555_IDF_REQUIRES driver

Version Header

The build system generates pcal95555_version.h from inc/pcal95555_version.h.in at configure time. It provides:

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#define HF_PCAL95555_VERSION_MAJOR  1
#define HF_PCAL95555_VERSION_MINOR  0
#define HF_PCAL95555_VERSION_PATCH  0
#define HF_PCAL95555_VERSION_STRING "1.0.0"

Include it in your application to verify at runtime which version is compiled in:

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#include "pcal95555_version.h"
printf("PCAL95555 driver v%s\n", HF_PCAL95555_VERSION_STRING);

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