This product is a real-time operating system (real-time OS) that is an implementation of the μITRON4.0 specification. μITRON is the predominant real-time OS for embedded systems in Japan. Its low resource requirements, outstanding real-time performance, and broad range of service calls make it very suitable for embedded systems requiring true real-time and multi-tasking capabilities.

In addition, its high degree of compatibility with the compiler package from Renesas Electronics and the configurator which automatically generates startup files will help you greatly reduce development times and get your products to market more quickly.

Successors:RI600V4 Real-time OS for RX Family



  • Conformance with the µITRON4.0 Specification
  • ROM-based implementation
  • Kernel building made easy by the configurator
  • Compatibility with the High-performance Embedded Workshop IDE will help you easily install the OS into your applications
  • Supported compiler: C/C++ Compiler Package for RX Family
  • Learn More

Release Information

Latest Ver.: V.1.01 Release 01
Released: Apr 16, 2013
Details of upgrade (See Tool News)
Operating Environment
Agreement Details
User's Manual: RI600/4 User's Manual (Real-time OS for RX Family) Rev.1.00 (PDF | English, 日本語)

Target Devices


Additional Details


RI600V4 Real-time OS for RX Family


The RI600/4 kernel consists of the following modules. Each module is provided by functions (service calls) .

  • Scheduler
    Manages execution sequence of multiple tasks based on their priority levels.
  • Task management
    Manages task status such as RUNNING, READY, WAITING or SUSPENDED.
  • Task-dependent synchronization
    Changes task status from other task, and synchronizes tasks.
  • Synchronization/communication
    Carries out synchronization and communication between tasks. The following function modules are available:
    • Semaphore
      An object for exclusive control of shared devices and variables for two or more tasks.
    • Event flag
      An object to control the execution of a task according to the AND/OR condition represented by bit pattern.
    • Data queue
      An object to perform 1-word (32 bits) communication.
    • Mail box
      An object to communicate an arbitrary-length message by pointer passing.
    • 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 length memory pool
    An object to dynamically allocate/free memory of preassign fixed size.
  • Variable length memory pool
    An object to dynamically allocate/free memory of arbitrary size.
  • Interrupt processing
    Returns from an interrupt handler, enables/disables an interrupt for each task, and so on.
  • Time management
    Sets system timer used by RI600/4 kernel and starts user-defined alarm handler, cyclic handler and overrun handler.
  • System configuration management
    Reports information such as version number of RI600/4 kernel.
  • System state management
    Modifies and refers system status.
  • Object reset function
    Initializes the Data queue, Mail box, Message buffer, Fixed length memory pool, Variable length memory pool. This function is unique to the RI600/4 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
Service call number 143
(Time takes for a target task to be executed after the wup_tas 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


vided items Explanation Note
Kernel source program Kernel source program Provided only with mass- production licenses which include source code.
Kernel library Kernel library for system building Compliant with big/little endian
Standard header files ・ITRON specification common definition files
・Kernel specification definition files
・Other definition files
Header files are provided both in C languages
GUI Configurator The input the construction parameters on the GUI screen allows the output of the cfg file for cfg600.
Command Line Configurator
Generates the various definition files from a cfg file on which construction parameters are described in plain text form.
Table generation utility
Generates the Interrupt Vector Table and Service Call Jump Table.
Manual user's manual

Processing Flow