STM32Cube Low-Layer API
STMicroelectronics released Low-Layer API for programming of all STM32 microcontrollers (except STM32H7). API is known like LL API, expert oriented set of APIs. The LL API can be easily combined with HAL (with a few restrictions).

Low-Layer API is included in software package called STM32Cube. LL API compliants MISRA-C 2004 standard, the API have been checked using Grammatech CodeSonar®.

LL API in STM32CubeMX is ready for STM32L0, STM32F0, STM32L4, a STM32F3 families of microcontrollers.
In additional months you can expect the support of another microcontrollers in STM32CubeMC and migration tool (SPL to LL API).

Press release: