The steps to create a microcontroller application using RTX5 are:

Create a new project and select a microcontroller device.
In the Manage Run-Time Environment window, select CMSIS::CORE, CMSIS::OS Tick (API)::SysTick and CMSIS::RTOS2 (API)::Keil RTX5. You can choose to either add RTX as a library (Variant: Library) or to add the full source code (Variant: Source) - required if using the Event Recorder:

Run-Time Environment for RTX5 in Keil uVision

If the Validation Output requires other components to be present, try to use the Resolve button.
Click OK. In the Project window, you will see the files that have been automatically added to you project, such as RTX_Config.h, RTX_Config.c, the library or the source code files, as well as the system and startup files:

RTX5 Project Window in Keil uVision

If using the Variant: Source as stated above, you have to assure to use at least C99 compiler mode (Project Options -> C/C++ -> C99 Mode).
You can add template files to the project by right-clicking on Source Group 1 and selecting Add New Item to 'Source Group 1'. In the new window, click on User Code Template. On the right-hand side you will see all available template files for CMSIS-RTOS RTX:

Adding RTX template files to the project

Configure RTX5 to the application's needs using the RTX_Config.h file.

Additional requirements for RTX on Cortex-A

Cortex-A based microcontrollers are less unified with respect to the interrupt and timer implementations used compared to M-class devices. Thus RTX requires additional components when an A-class device is used, namely CMSIS-Core IRQ Controller (API) and OS Tick (API) implementations.

Keil uVision Run-Time Environment for RTX5 on Cortex-A

The default implementations provided along with CMSIS are

Arm Generic Interrupt Controller (GIC)
Arm Cortex-A5, Cortex-A9 Private Timer (PTIM)
Arm Cortex-A7 Generic Physical Timer (GTIM)

For devices not implementing GIC, PTIM nor GTIM please refer to the according device family pack and select the proper implementations.

Add support for RTX specific functions

If you require some of the RTX specific functions in your application code, #include the header file rtx_os.h. This enables low-power and tick-less operation modes.

RTX5 Header File

Every implementation of the CMSIS-RTOS2 API can bring its own additional features. RTX5 adds a couple of functions for the idle more, for error notifications, and special system timer functions. It is also using macros for control block and memory sizes.

If you require some of the RTX specific functions in your application code, include the header file rtx_os.h:

#include "rtx_os.h"

Add Event Recorder Visibility

RTX5 interfaces to the Event Recorder to provide event information which helps you to understand and analyze the operation.

To use the Event Recorder together with RTX5, select the software component CMSIS-View:Event Recorder.
Select the Source variant of the software component CMSIS:RTOS2 (API):Keil RTX5.

Component selection for Event Recorder

Enable the related settings under Event Recorder Configuration.
Build the application code and download it to the debug hardware.

Once the target application generates event information, it can be viewed in the µVision debugger using the EventRecorder.

Building the RTX5 Library

The CMSIS Pack contains a csolution project for building the complete set of RTX5 libraries. This project can also be used as a reference for building the RTX5 libraries using a tool-chain of your choice.

Build Process

The build process is managed using the following files:

RTX_Library.csolution.yml: Defines the solution configuration.
RTX_Library.cproject.yml: Specifies the project settings.
build.sh: Script that triggers the library build process.

Libraries Built

The following table lists the files available in the build output directory, its target architecture with additional attributes and target toolchain.

Library Name	Target Architecture (attributes)	AC6	GCC	IAR	CLANG
`RTX_V6M`	Arm v6-M	YES	YES	YES	YES
`RTX_V7A`	Arm v7-A	YES	YES	YES	NO
`RTX_V7M`	Arm v7-M	YES	YES	YES	YES
`RTX_V7MF`	Arm v7-M (FP)	YES	YES	YES	YES
`RTX_V8MB`	Arm v8M Base Line	YES	YES	YES	YES
`RTX_V8MBN`	Arm v8M Base Line (non-secure)	YES	YES	YES	YES
`RTX_V8MM`	Arm v8M Main Line	YES	YES	YES	YES
`RTX_V8MMF`	Arm v8M Main Line (FP)	YES	YES	YES	YES
`RTX_V8MMFN`	Arm v8M Main Line (FP, non-secure)	YES	YES	YES	YES
`RTX_V8MMN`	Arm v8M Main Line (non-secure)	YES	YES	YES	YES
`RTX_V81MM`	Arm v8.1M Main Line	NO	NO	YES	NO
`RTX_V81MMF`	Arm v8.1M Main Line (FP)	NO	NO	YES	NO
`RTX_V81MMFN`	Arm v8.1M Main Line (FP, non-secure)	NO	NO	YES	NO
`RTX_V81MMN`	Arm v8.1M Main Line (non-secure)	NO	NO	YES	NO

FP: library built with Floating Point support
non-secure: library built for TrustZone non-secure domain

All RTX5 libraries are built with debug information produced for use by a debugger.

Optimization

The build process optimizes RTX5 libraries for size, which translates to the following per compiler compiler options:

Compiler	Optimization Option
AC6	-Oz
GCC	-Os
IAR	-Ohz
CLANG	-Os