ARM-software/CMSIS_5
FreeCMSIS Version 5 Development Repository
FreeFree tier
About ARM-software/CMSIS_5
CMSIS Version 5 is an open-source development repository by ARM-software that provides a standardized hardware abstraction layer for ARM Cortex-M and Cortex-A processors. It includes components for core access (CMSIS-Core(M) and Core(A)), generic peripheral driver interfaces (CMSIS-Driver), efficient neural network kernels (CMSIS-NN), common RTOS APIs (CMSIS-RTOS v1 and v2), a software delivery mechanism (CMSIS-Pack), build tools (CMSIS-Build), peripheral description (CMSIS-SVD), debug access port firmware (CMSIS-DAP), and system resource partitioning (CMSIS-Zone). The repository is now archived; users are encouraged to migrate to CMSIS Version 6.
Key Features
Standardized API for Cortex-M processor core and peripherals (CMSIS-Core(M))
API and runtime system for Cortex-A5/A7/A9 (CMSIS-Core(A))
Generic peripheral driver interfaces for middleware (CMSIS-Driver)
Efficient neural network kernels optimized for Cortex-M (CMSIS-NN)
Common RTOS API with reference implementation (CMSIS-RTOS v1 and v2)
Software delivery and pack management (CMSIS-Pack)
Set of build tools and CI workflows (CMSIS-Build)
Peripheral description for debuggers (CMSIS-SVD)
Debug Access Port firmware (CMSIS-DAP)
System resource and partitioning description (CMSIS-Zone)
Pros & Cons
Pros
- Open source and free to use
- Widely adopted industry standard for ARM Cortex processors
- Comprehensive set of components covering core, drivers, NN, RTOS, and debug
- Optimized neural network kernels reduce memory and computational overhead
- Backward compatible with CMSIS v6 migration path
Cons
- Repository is archived and no longer actively developed (migrate to v6)
- Limited to ARM Cortex-M and Cortex-A processors
- Steep learning curve for beginners due to extensive component set
Best For
Embedded software development for ARM Cortex-M and Cortex-A microcontrollersDeveloping neural network inference on resource-constrained MCUsCreating real-time operating systems with standardized APIDebugging and profiling embedded systemsPackaging and distributing device software components
FAQ
What is CMSIS?
CMSIS (Cortex Microcontroller Software Interface Standard) is a vendor-independent hardware abstraction layer for ARM Cortex-M and Cortex-A processors that includes APIs, drivers, and middleware components.
Is CMSIS-5 still maintained?
The CMSIS_5 repository is archived and read-only. Users are encouraged to migrate to CMSIS Version 6 for continued support and improvements.
What processors are supported?
CMSIS-5 supports ARM Cortex-M (including SecurCore) and Cortex-A5/A7/A9 processors.