CMSIS-Compiler provides software components that simplify retargeting of standard C run-time library functions.

Application code frequently uses standard C library functions, such as fopen, fwrite, printf(), scanf() and others to perform input/output operations. These functions may as well be used in a multithreaded environment.

The structure of these functions in the standard C run-time library together with the retarget interfaces is:

Software Structure Overview

Standard C library functions are platform independent and can be easily ported, while the low-level interfaces needs to be tailored to the chosen platform. Generally low-level I/O functions serve to interact with the file system and a serial interface, i.e. terminal. Multithreading support is available for applications that run on top of an RTOS kernel.

CMSIS-Compiler enables platform specific retargeting by providing software components that break down into the following interfaces:

File interface that enables reading and writing files
STDIN interface that enables standard input stream redirection
STDOUT interface that enables standard output stream redirection
STDERR interface that enables standard error stream redirection
OS interface that enables multithread safety using an arbitrary RTOS

The pages Low-Level I/O Retarget and Multithreading Support Retarget explain the details about how retargeting is done using the provided components.

Using CMSIS-Compiler developers can retarget standard I/O streams and file operations to specific platform and enable thread safe operations using RTOS interface.

‍Note

CMSIS-Compiler replaces and extends retargeting functionality previously provided as part of Keil::ARM_Compiler pack.

See Migrating projects from CMSIS v5 to CMSIS v6 for a guidance on updating existing projects to CMSIS-Compiler.

Supported Toolchains

The CMSIS-Compiler component is available for the following toolchains:

Support for IAR Compiler support will be added in a future revision of the CMSIS-Compiler.

Access to CMSIS-Compiler

CMSIS-View is actively maintained in CMSIS-Compiler GitHub repository and is released as a standalone CMSIS-Compiler pack in the CMSIS-Pack format.

The table below explains the content of ARM::CMSIS-Compiler pack.

Directory	Description
📂 documentation	Folder with this CMSIS-Compiler documenation
📂 example	I/O Retarget example project
📂 include	Header files with Retargeting functions
📂 source	Compiler-specific implementations of regargeting functions
📂 template	User Template files
📄 ARM.CMSIS-Compiler.pdsc	CMSIS-Pack description file
📄 LICENSE	License Agreement (Apache 2.0)

See CMSIS Documentation for an overview of CMSIS software components, tools and specifications.

Documentation Structure

This documentation contains the following sections:

Revision History : lists CMSIS-Compiler releases.
Low-Level I/O Retarget : explains low-level I/O retargeting, list available components and describes available user code templates.
Multithreading Support Retarget : explains multithreading support retargeting, list available components and describes available user code templates.
The I/O Retarget example project shows how to retarget the output to a UART on an Arm Virtual Hardware model.
Templates : contains the user code template files for the different use cases.
API Reference describes the API and the functions of the CMSIS-Compiler components in details.

License

CMSIS-Compiler is provided free of charge by Arm under the Apache 2.0 License