This repo provides a version of ST Microelectronics’ STM32 Standard Peripheral Library that has been modified to support Microvisor running on an STM32U585 microcontroller.

It is a repackaging and expansion of ST Microelectronics’ STM32CubeU5 hardware abstraction layer (HAL).

The key difference between the STM32CubeU5 HAL and the Microvisor version is that direct accesses to RCC by non-secure code, which are not permitted under Microvisor, are here intercepted and actioned by Microvisor.

This ensures that standard library functions such as __HAL_RCC_GPIOA_CLK_ENABLE(), LL_RCC_WriteReg(), etc. can continue to be called as if they were running without Microvisor present. The intention is to make it as easy as possible to port a “bare metal” implementation to Microvisor.

For supported peripherals, accesses are mediated by the Microvisor non-secure system call functions mvPeriphPeek32() and mvPeriphPoke32(). These functions are declared in mv_syscalls.h and allow certain registers within supported peripherals to have read/write access to defined bits within those registers.

This is particularly important for RCC as without such support, non-secure code would not be able to determine the bus and clock frequencies which are needed to configure other peripherals, such as UARTs.

• RCC

To make use of the HAL, you should follow ST Microelectronics’ HAL documentation (PDF).

Note Access to this document may require signing in to the ST Microelectronics website.

Build the image:

docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) -t microvisor-hal-stm32u5 .

Run the build:

docker run -it --rm -v $(pwd)/:/home/ --name lib-microvisor-hal-stm32u5 microvisor-hal-stm32u5

This build mode has the following dependencies:

• cmake
• gcc-arm-none-eabi — tested with 9-2019-q4

Prepare to build:

• Generate the Makefiles and project:

cmake -S . -B build

• Build the executable:

cmake --build build --clean-first

The library will be built into build/libmicrovisor-hal-stm32u5.a.

Note The included CMakeFiles.txt is a “kitchen sink“ inclusion of the HAL. However, you can restrict the included files from the HAL to just those your project may need. An example of this approach is demonstrated in our FreeRTOS sample.

You can then link your code against the Microvisor port of the Standard Peripheral Library, rather than the Standard Peripheral Library itself.

Alternatively, you can import the entire repository instead of importing the Standard Peripheral Library.

Note The file mv_prescalers.c is not required if you already have a target in your project that defines the relevant prescaler values.

Please contact Microvisor Support.

Code authored by KORE Wireless is made available under the terms of the Apache 2.0 license and is © 2021-23, KORE Wireless.

All other code is licensed as described in the linked file and is © 2021, STMicroelectronics and affiliates.