This product is a real-time operating system (Real-time OS) conforming to the µITRON4.0 Specification, the predominant Real-time OS for embedded systems in Japan. Its compact resources, outstanding real-time features, and many service calls are suited for an embedded system with real-time ability and multi-tasking functions. In addition, its affinity for the IDE CS+ and e2 studio, and the configurator which automatically generates startup files will help you greatly reduce development time and get to market faster.

Note: RI600V4 is not generally promoted to U.S. and European customers. Customers in U.S. and Europe who are interested in RI600V4 are requested to contact our regional marketing departments for details.

  • TRON Forum holds the copyright on the μITRON Specification.
  • TRON, ITRON, and μITRON do not refer to any specific product or products.
  • The activities of TRON Association have been handed over to TRON Forum.


  • The register bank save function (optional function for the RXv3 architecture) is now supported.
  • The performance has been improved in case of not using the Task Analyzer.

Learn More (Tool News) >>

Release Information


Latest Ver.: V1.06.00

Released: Jul 22, 2019

Details of upgrade (See Tool News)


When you build a sample program V1.05.00 or earlier, the warning (below) will be output.

O4001 (W) : system.max_regbank is not defined

For a workaround, see the following section in the  release note 6.3.2. Configurator (1)Register Bank Save Function is supported

Operating Environment

Agreement Details

 User's Manual( Coding | All )

CS+ interface plug-ins (Real-time OS Common plug-in)

Latest Ver.: V3.03.00

Released: Jul 1, 2016

CS+ interface plug-ins (Plug-in for RI600V4)

Latest Ver.: V3.01.01

Released: Nov 27, 2018

Integrated Tools

  • Compiler: CC-RX
  • Integrated development environment: CS+e2 studio


  • Compliant with µITRON4.0 Specification
    The design conforms to the µITRON4.0 Specification, the representative OS architecture for embedded control.
  • The register-bank save function accelerates the saving and restoring of register values
    The register-bank save function (optional function for the RXv3 architecture) is now supported. The register-bank save function increases the speed and precision of interrupt handling.
    The register-bank save function is available for tasks, interrupt handlers, and fixed interrupt handlers in RI600V4.
    Performance when using the register-bank save function (compared with not using this function)
      Time for switching tasks (Note1) Interrupt response times
    Item measured *on an RX72T (at 100 MHz) without the trace function
    Measurement case A About 18 % faster About 19 % faster RXv2 library (Note2): Without register-bank save function (Not available on the RXv2)
    RXv3 library (Note3): With the register-bank save function
    Measurement case B About 15 % faster About 13 % faster RXv3 library (Note3): Without register-bank save function
    RXv3 library (Note3): With the register-bank save function
    • Note1. Not accompanied by interrupts
    • Note2. This kernel library was built with CC-RX V2.04.01 (and is included in V1.04.00 and later versions of the RI600V4 OS).
    • Note3. This kernel library was built with CC-RX V3.01.00 (and is included in V1.04.00 and later versions of the RI600V4 OS).
    • * These data were gathered under specific conditions, and we do not guarantee a specific increase in speed.
  • ROM-based implementation:
    Since the system is a real-time/multi-tasking OS assumed to be used embedded in the execution environment, it was designed to be compact and ready for ROM-based implementations. Also, because the system can be configured linking only the service calls used in the system by the user (rather than all the service calls provided by the RI600V4), a real-time/multi-tasking OS can be configured which is compact and optimized for the user's needs.
  • Interface with CS+ and e2 studio, the Renesas Electronics Integrated Development Environment
    The RI600V4 OS interfaces with CS+ and e2 studio to support the following functions:
    • Auto-settings for options required in OS build
    • Displays state of OS control object for tasks, semaphore, etc. (Resource Information)
    • Graphical display of task operation logs and service call issue logs (Task Analyzer).

    CS+ (Resource Information)

    CS+ (Task Analyzer)

  • Sample Projects (CS+ edition) Provided for FIT (support for the RXV3 core is in planning)
    Sample projects (CS+ edition) for the use of Firmware Integration Technology (FIT) with the RI600V4 real-time operating systems (Real-time OS) for the RX family are supplied.
    Download the sample project for FIT from Downloads Tab.
  • Improvements in processing speed (compared with V1.05.00)
    The speed performance has been improved in case of not using the Task Analyzer.
    The time for switching tasks shortened by about 4%, the interrupt response times shortened by about 7%.
    Note: These data were gathered under specific conditions, and we do not guarantee a specific increase in speed.


The RI600V4 kernel consists of the following modules. Each module is provided by functions (service calls) .

  • Task management functions
    Provided by the RI600V4 include a function to reference task statuses such as priorities and detailed task information, in addition to a function to manipulate task statuses such as activation and termination of tasks.
  • Task dependent synchronization functions
    Changes task status from other task, and synchronizes tasks.
  • Synchronization and communication functions
    The synchronization and communication functions of the RI600V4 consist of Semaphores, Eventflags, Data Queues, Mailboxes, Mutex, and Message buffer that are provided as means for realizing exclusive control, queuing, and communication among tasks.
    • Semaphores:
      In the RI600V4, semaphores are provided as a means (exclusive control function) for preventing contention for limited resources (hardware devices, library function, etc.) arising from the required conditions of simultaneously running tasks.
    • Eventflags:
      Provides 32-bit eventflags as a queuing function for tasks.Data Queues:
      Provides the data queues that have the data queue area in which data read/write is enabled for transferring the prescribed size(4 bytes) of data.
    • Mailboxes:
      Provides a mailbox, as a communication function between tasks, that hands over the execution result of a given processing program to another processing program.
    • Mutex
      An object to perform exclusive control, and providing support for the feature to avoid priority inversion problems.
    • Message buffer
      An object to communicate an arbitrary-length message by copying.
  • Fixed-sized memory pool
    A function to dynamically allocate/free memory of preassign fixed size.
  • Variable-sized memory pool
    A function to dynamically allocate/free memory of arbitrary size.
  • Time management functions
    Provides methods to implement time-related processing (Timer Operations: Delayed task wakeup, Timeout, Cyclic handlers, and Alarm handlers) by using base clock timer interrupts that occur at constant intervals, as well as a function to manipulate and reference the system time. When using the time management function, it is necessary to specify the timer template file corresponding to the target device in the system configuration file.
  • System state management
    Provides functions for referencing the system status such as the context type and CPU lock status, as well as functions for manipulating the system status such as ready queue rotation, scheduler activation, or the like.
  • Interrupt processing
    Provides functions about interrupt handler that is called when an interrupt is occurred.
  • System configuration management
    Reports information such as version number of RI600V4 kernel.
  • Object reset function
    Initializes the Data queue, Mail box, Message buffer, Fixed-sized memory pool, Variable-sized memory pool. This function is unique to the RI600V4 and is not defined in the µITRON4.0 specifications.

Kernel specifications

Target CPU RX Family
Maximum number of tasks 255
Number of priority levels 255
Number of Service calls 143
Performance (Time takes for a target task to be executed after the wup_tsk is issued.) 2.5 microseconds (RX610, 100MHz)
Kernel code size From 6.2K bytes to 25.5K bytes
Kernel RAM usage per task data : 16 bytes
stack : 44 bytes


Provided items Explanation Note
Kernel source program Source files for the kernel Provided only with mass- production licenses which include source code.
Kernel library Kernel library for system building -
Standard header files
  • ITRON specification common definition files
  • Kernel specification definition files
  • Other definition files
Header files are provided in C language.
GUI Configurator The input the construction parameters on the GUI screen allows the output of the cfg file for cfg600. -
Command line configurator Outputs all types of definition files from the cfg file that describes the structure parameters in text. -
Sample program A simple program using ITRON. -
CS+ interface plug-ins
  • Real-time OS Common plug-in
  • Plug-in for RI600V4
  • Function for easy kernel embedding
  • Function for referencing the OS state during debug
Manual User's manual -

Processing Flow

About Trial

We provide a trial software of the RI600V4 so that you can try out the functions and performance of RI600V4 before purchasing it. No support, including responses to inquiries through contact points, is provided for the trial software. Please accept this before using the trial software. In addition, please read through the  Software User License Agreement and following notes before downloading.

Before Downloading

Cautionary Notes

  1. Difference with the Product Version
    Although the performance and functionality are the same as the product version, the trial software has the restrictions described below.
    • The RI600V4 real-time OS is forcibly shut down after running for an hour.
    • When the OS is shut down, the program jumps to the system down routine "_RI_sys_dwn__".
    • At this time, -64(0xffffffc0) is passed to the first argument, "type", of "_RI_sys_dwn__".
  2. Using the OS for Finished Products
    If you intend to embed the RI600V4 real-time OS in a finished product, use the product version. We do not offer any technical support services in case of troubles by using trial software.
  3. Prohibition of Redistribution
    Redistribution of the software tool to third parties is strictly prohibited.

Operating Environment

The operating environment is same as the product version. Refer to Operating Environments of Products.


We provide the CS+ and e2 studio version of the RI600V4 Trial software.

Note on Running the Product on e2 studio

If two or more e2 studio applications have been installed on the host PC, execute the following file before you start e2 studio application you want to use.

File to be executed:
<e2 studio install folder>¥eclipse¥plugins¥com.renesas.renesasos.plugins_<version>¥CSPlus¥Plugins¥OsRegister.exe

cd C:¥Renesas¥e2studio¥eclipse¥plugins¥com.renesas.renesasos.plugins_1.0.0.201408071907¥CSPlus¥Plugins¥OsRegister.exe

Depending on the memory configuration of the device, it may not be applicable.

Information supporting development tools

Title Description
My Renesas Create a My Renesas account to use our tool download services,
receive e-newsletter/update notifications, and take advantage of our other services.
e-learning Information for studying and learning about microcontrollers and microprocessors.
FAQ Frequently asked questions and useful hints for development.
Forum A forum and community site to share technical information,
questions and opinions with others who use Renesas MCU's.
Tool News Tool release information and other important information.
Operating Environment Information on system requirements and operating environment for the latest
version of tools.
Info on Discontinued Products A list of Renesas software and tools that have been discontinued and
are no longer being offered for new projects.