A library of basic drivers for microcontrollers. It is written using the C23 standard and CMake.

Library supports the following platforms:

• x86 — minimal implementation provided for testing other projects and for development/debugging purposes on desktop systems
• NXP LPC82x, LPC11xx, LPC11Exx, LPC13xx, LPC13Uxx, LPC17xx, LPC43xx; for LPC43xx, both the main M4 core and auxiliary M0 cores are supported
• NXP i.MX RT106x, currently has initial support
• STMicro STM32F0, STM32F1, STM32F4
• Nuvoton M03x, M48x
• Bouffalo Lab BL602/BL604, currently has initial support

Note: Platform support levels may vary, platforms with "initial support" have limited driver availability.

To build and use the library, you need the following software installed on your system:

• GCC 13 or newer — the GNU Compiler Collection, required for building the x86 version.
• ARM GCC 13 or newer — Arm GNU Toolchain, required for Cortex-M embedded targets.
• RISC-V GCC 13 or newer — RISC-V GNU Toolchain, required for RISC-V embedded targets.
• CMake 3.21 or newer — used for configuring and generating build systems across platforms.
• Kconfiglib or kconfig‑frontends — tools for interactive library configuration via menuconfig.
• Xcore — can be built separately or included as CMake submodule in the top-level project.

The library includes the following major components:

Provides low‑level access to hardware peripherals, with a consistent API across platforms. Supports the following peripherals:

• ADC and DAC
• DMA
• GPIO
• Timers and watchdog
• External interrupts
• UART, SPI, I2C, I2S, CAN, SDIO (in blocking and zero‑copy modes)
• QSPI and specialized peripherals with XIP
• USB FS and HS
• Ethernet
• Built‑in flash memory and EEPROM
• External parallel SRAM and SDRAM
• Clock management and power saving
• Specialized peripherals

Higher‑level software components that abstract common patterns:

• Software timers
• Task queues
• SDIO via SPI and SD/MMC

Support for USB device functionality:

• Platform‑dependent parts
• Platform‑independent drivers for CDC, HID, MSC and UAC
• Composite devices

Below are common scenarios for using the library in your projects.

1. Including in a CMake Project

To include the library as a subdirectory in your CMake project, use add_subdirectory and specify the configuration file via the HALM_CONFIG_FILE variable:

add_subdirectory("/path/to/halm" halm)

Make sure to set the HALM_CONFIG_FILE variable to point to your configuration file before including the library. This file defines which drivers and features are compiled in.

Example in CMakeLists.txt:

set(HALM_CONFIG_FILE "${CMAKE_CURRENT_SOURCE_DIR}/halm.config")
add_subdirectory("/path/to/halm" halm)

2. Building for x86 Outside the Project Tree

When building for x86 outside the project tree, configure the library using menuconfig and build:

make menuconfig
cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/output/dir/ \
  -DCMAKE_PREFIX_PATH=/path/to/output/dir/
make
make install

3. Building for LPC175x Outside the Project Tree

For building under LPC175x outside the project tree, use the following commands:

make menuconfig
cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/output/dir/ \
  -DCMAKE_PREFIX_PATH=/path/to/output/dir/ \
  -DCMAKE_TOOLCHAIN_FILE=/path/to/xcore/toolchains/cortex-m3.cmake \
  -DPLATFORM=LPC17XX
make
make install

The toolchain file sets up the cross‑compiler, and the PLATFORM variable tells which MCU‑specific code to include.

The following build options are available to customize your build:

• PLATFORM — specifies the target platform for the build. Possible values:

  IMXRT106X — NXP i.MX RT106x series
  LPC82X — NXP LPC82x series
  LPC11XX — NXP LPC11xx series
  LPC11EXX — NXP LPC11Exx series
  LPC13XX — NXP LPC13xx series
  LPC13UXX — NXP LPC13Uxx series
  LPC17XX — NXP LPC175x and LPC176x series
  LPC43XX — NXP LPC43xx series (main M4 core)
  LPC43XX_M0APP — NXP LPC43xx series, M0 application core
  LPC43XX_M0SUB — NXP LPC43xx series, M0 subcore
  M03X — Nuvoton M03x series
  M48X — Nuvoton M48x series
  STM32F0XX — STMicro STM32F0 series
  STM32F1XX — STMicro STM32F1 series
  STM32F4XX — STMicro STM32F4 series
  BL602 — Bouffalo Lab BL602/BL604 series
  

  If the PLATFORM option is omitted, x86 target is used.

• HALM_CONFIG_FILE — path to the library configuration file (.config). This file can be created or edited using menuconfig. It defines the features, peripherals, and drivers to be included in the build.