Software library

AN2945

14/18

Doc ID 15468

4

Software library

Peripheral compatibility throughout ST’s STM8 and STM32 MCU families promotes platform

design and helps significantly switch from one product line to the other. When it comes to

development time, however, software support is essential. Extensive software libraries are

available for both the STM8S and STM32 devices, providing the user with a hardware

abstraction layer (HAL) for all MCU resources. Moreover, there is not a single control/status

bit that is not covered by a C function or an API.

The software library covers three abstraction levels, and it includes:

1.

a complete register address map with all bits, bit fields and registers declared in C. By

providing this map, the software library makes the designers’ task much lighter and,

even more importantly so, it gives all the benefits of a bug-free reference mapping file,

thus speeding up the early project phase.

2.

a collection of routines and data structures in API form, that covers all peripheral

functions. This collection can directly be used as a reference framework, since it also

includes macros for supporting core-related intrinsic features and common constant

and data type definition. Moreover, it is compiler agnostic and can therefore be used

with any existing or future toolchain. It was developed using the MISRA C automotive

standard.

3.

a set of examples covering all available IPs (85 examples so far for the STM32 family,

57 for the STM8S family), with template projects for the most common development

toolchains. With the appropriate hardware evaluation board, only a few hours are

needed to get started with a brand new microcontroller.

It is then up to you to choose how to use the library. You can either pick up the files useful for

the design, use examples to get trained or quickly evaluate the product. You can also use

the API to save development time.

Let us now have a look at the few key files and concepts. Two separate libraries support the

STM8S and STM32F devices. In the file names below, you simply need to replace the

“stmxxx_” prefix by “stm32f10x” or “stm8s” depending on the chosen product.

●

stmxxx_.h

This file is the only header file that must be included in the C source code, usually in

main.c. This file contains:

–

data structures and address mapping for all peripherals

–

macros to access peripheral register hardware (for bit manipulation for instance),

plus STM8S core intrinsics

–

a configuration section used to select the device implemented in the target

application. You also have the choice to use or not the peripheral drivers in the

application code (that is code based on direct access to registers rather than

through API drivers)

●

stmxxx_conf.h

This is the peripheral driver configuration file, where you specify the peripherals you

wants to use in your application, plus a few application-specific parameters such as the

crystal frequency.

●

stmxxx_it.c

This file contains the template IRQ handler to be filled, but this is already the first

development step!