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. CI builds with GCC and Clang on Ubuntu 24.04, and with the ESP-IDF toolchain.
CMake 3.16 or newer, which also generates the version header.
No RTOS, heap or exceptions: every call is noexcept and returns bool or a value.

Get the source¶

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

git submodule add https://github.com/hardfoc/hf-mcp9700-driver.git external/hf-mcp9700-driver
git submodule update --init external/hf-mcp9700-driver

Only inc/, src/, 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-mcp9700-driver)
target_link_libraries(my_app PRIVATE hf::mcp9700)

hf::mcp9700 is an alias of the hf_mcp9700 INTERFACE target. It carries both include directories (inc/ and the generated mcp9700_version.h) and requires C++17 (cxx_std_17), so your target does not need to set either.

Option	Default	Effect
`HF_MCP9700_ENABLE_WARNINGS`	`OFF`	Deprecated, no effect (prints a deprecation message). Set warnings on your own target
`HF_MCP9700_BUILD_TESTS`	`OFF`	Builds the host unit tests in `tests/` (Testing and CI)

Install and find_package¶

cmake --install copies the header, the .ipp, the generated mcp9700_version.h and a package configuration:

cmake -S external/hf-mcp9700-driver -B build-mcp9700
cmake --install build-mcp9700 --prefix /opt/hardfoc

Installed path	Contents
`include/hf_mcp9700/inc/`	`mcp9700_thermistor.hpp`, `mcp9700_version.h`
`include/hf_mcp9700/src/`	`mcp9700_thermistor.ipp`, included by the header as `../src/`
`lib/cmake/hf_mcp9700/`	`hf_mcp9700Config.cmake`, `hf_mcp9700ConfigVersion.cmake`, `hf_mcp9700Targets.cmake`

A consumer then finds the same hf::mcp9700 target. Point CMAKE_PREFIX_PATH at the install prefix:

find_package(hf_mcp9700 1.0 REQUIRED)
target_link_libraries(my_app PRIVATE hf::mcp9700)

The version check accepts any 1.x release (SameMajorVersion).

Without the root CMakeLists¶

Include cmake/hf_mcp9700_build_settings.cmake and add HF_MCP9700_PUBLIC_INCLUDE_DIRS to your target. Including the file is what generates mcp9700_version.h (into hf_mcp9700_generated/ under the current binary directory); mcp9700_thermistor.hpp does not compile without it.

include(${CMAKE_CURRENT_SOURCE_DIR}/external/hf-mcp9700-driver/cmake/hf_mcp9700_build_settings.cmake)
target_include_directories(my_app PRIVATE ${HF_MCP9700_PUBLIC_INCLUDE_DIRS})
target_compile_features(my_app PRIVATE cxx_std_17)

ESP-IDF¶

The ESP-IDF component wrapper is examples/esp32/components/hf_mcp9700/. Copy that folder into your project's components/ (or point EXTRA_COMPONENT_DIRS at it) and set the HF_MCP9700_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_mcp9700.

How the build is organised¶

File	Role
`cmake/hf_mcp9700_build_settings.cmake`	Include directories, version, IDF dependencies: the single source of truth
`CMakeLists.txt`	`INTERFACE` target for host builds and CI, install rules
`cmake/hf_mcp9700Config.cmake.in`	Package configuration for `find_package(hf_mcp9700)`
`examples/esp32/components/hf_mcp9700/`	ESP-IDF component wrapper over the same settings

The version is set once in the settings file and written into mcp9700_version.h at configure time, as HF_MCP9700_VERSION_MAJOR, _MINOR, _PATCH and HF_MCP9700_VERSION_STRING. Read it at run time:

const char* v = GetMcp9700DriverVersion();   // "1.0.0"

Compile-time switches¶

There are none. The coefficients are constructor arguments, not macros (Configuration).

Next¶

Quickstart wires the sensor and reads a temperature; Porting writes the ADC adapter for your MCU.