Installation¶

Add the driver to a CMake or ESP-IDF project. It is a header-only C++17 library with no dependencies.

Requirements¶

A C++17 compiler: GCC 7+, Clang 5+ or a current MSVC.
No RTOS, heap or exceptions: every call is noexcept and returns at25040::Status.

Get the source¶

A git submodule keeps the driver pinned to a version you chose:

git submodule add https://github.com/hardfoc/hf-at25040-driver.git external/hf-at25040-driver
git submodule update --init external/hf-at25040-driver

Only inc/, cmake/ and CMakeLists.txt are needed to build. The examples have their own submodule (examples/esp32/scripts); you do not need it to use the driver.

CMake¶

add_subdirectory(external/hf-at25040-driver)
target_link_libraries(my_app PRIVATE hf_at25040)   # or the alias hf::at25040

hf_at25040 is an INTERFACE target: it carries the include directories (inc/ and the generated version header) and requires C++17 (cxx_std_17), so your target does not need to set either.

Option	Default	Effect
`HF_AT25040_BUILD_TESTS`	`OFF`	Builds the host unit tests and the documentation snippets in `tests/` (Testing and CI)

Installed package¶

cmake --install copies the headers (at25040.hpp, at25040_registers.hpp, at25040_spi_interface.hpp and the generated at25040_version.h) to include/ and a CMake package to lib/cmake/hf_at25040/, which provides the same target name as the build tree:

cmake -S external/hf-at25040-driver -B build-at25040
cmake --install build-at25040 --prefix /opt/hardfoc

find_package(hf_at25040 CONFIG REQUIRED)            # CMAKE_PREFIX_PATH=/opt/hardfoc
target_link_libraries(my_app PRIVATE hf::at25040)

Without CMake, add inc/ to the include path. at25040.hpp then falls back to a built-in version string.

ESP-IDF¶

The ESP-IDF component wrapper is examples/esp32/components/hf_at25040/. Copy that folder into your project's components/ (or point EXTRA_COMPONENT_DIRS at it) and set the HF_AT25040_ROOT cache variable to the driver checkout; the wrapper stops with a clear message when the path is wrong. Your component then declares REQUIRES hf_at25040.

Inside hf-core¶

In the HardFOC core, the driver is a submodule of hf-core-drivers and is switched on with HF_CORE_ENABLE_AT25040, which also compiles the At25040Handler:

set(HF_CORE_ENABLE_AT25040 ON)
include("${HF_CORE_DRIVER_EXT}/hf-at25040-driver/cmake/hf_at25040_build_settings.cmake")

How the build is organised¶

Layer	File	Role
Settings	`cmake/hf_at25040_build_settings.cmake`	Target name, include directories, version: the single source of truth
Library	`CMakeLists.txt`	`INTERFACE` target for host builds and CI, install and `hf::at25040` export
ESP-IDF	`examples/esp32/components/hf_at25040/CMakeLists.txt`	IDF component wrapper over the same settings

The version is set once in the settings file and written into at25040_version.h at configure time. Read it at run time:

const char* v = at25040::GetAt25040DriverVersion();   // "1.0.0"

Next¶

Quickstart wires the chip and stores a few bytes; Porting writes the SPI interface for your MCU.