University of Tokyo professor Ken Sakamura advocated the TRON project in 1984. The µITRON specification is one of the real-time operating system specifications standardized in the ITRON project established as a subproject of the TRON project. The µITRON specification is now a de facto standard in the Japanese embedded industry.

Renesas Electronics Corp. has been participating in the TRON project since the project was established. [HI series OS] is a realtime operating system for the Renesas H8/SuperH microcomputers which is compliant with µITRON specifications.

  • 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.

Supported CPU Cores

SH-1, SH-2, SH2-DSP, SH-2A, SH2A-FPU
*FPU of the SH-2E is not supported.


Release Information

Latest Ver.: V.2.03 Release 01Released: Nov 01, 2011

Details of upgrade (See Tool News)

Operating Environment

Agreement Details


  • Conforms to industry standard μITRON 4.0 specifications
    • HI series OS conforms to the µITRON 4.0 specifications, and is the dedicated real-time OS for Renesas SuperH microcomputers.
  • Real-time performance
    • The latest HI7000/4 realizes a fast task switching* of 5.6microseconds.
      *Time it takes a target task to be activated after a wup_tsk is issued. (SH704x@33.3MHz, when on-chip memory is used)
  • Superb functionality
    • Supports more than 100 service calls, such as the dynamic task generation system call. They support various applications.
  • Configurator
    • In the specifications of the HI7000/4 series of uITRON4.0, a configurator is equipped which makes the setup of OS construction parameters easier.


Screen Image : Configurator


  • Debugging Extension (option)
    • The Debugging Extension is an optional software which extends the multi-task functionality in High-performance Embedded Workshop, and can be downloaded for free from the website.
  • The following functionalities are offered by the Debugging Extension.
    • Shows the object status of tasks and semaphores managed by OS
    • Issues the service calls for task activation and event flag setting etc.
    • Displays the service call history
    • Graphically-displayed service call history

Screen Image : Debugging Extension


  • Cooperation with 3rd parties
    • We provide various solutions to deliver great environments for debugger/application software development, distribution of middleware, customization, and hardware platform etc. in conjunction with our partner vendors.


The HI7000/4 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.
  • Interrupt processing
    Returns from an interrupt handler
  • Time management
    Sets system timer used by HI7000/4 kernel and starts user-defined alarm handler, cyclic handler and overrun handler.
  • System State Management
    Reports information such as version number of HI7000/4 kernel.
  • Synchronization/communication
    Carries out synchronization and communication between tasks. The following function modules are available:
    • Event flag
      Tasks are synchronized by the status of flags managed by the kernel.
    • Semaphore
      Tasks are synchronized by the semaphore counter value managed by the kernel.
    • Mail box
      Tasks are synchronized by sending or receiving a message.
    • Data queue
      Tasks are synchronized by communicating 4-byte data.
  • Extended Synchronization/Communication
    Carries out synchronization and communication between tasks. The following function modules are available:
    • Message buffer
      Makes use of variable-length data communication to synchronize tasks.
    • Mutex
      Makes use of priority ceiling protocol for avoiding priority inversion to synchronize tasks.
  • Memory pool management
    Dynamically allocates/frees memory area used by tasks. Enables efficient use of memory.
  • Task exception
    Controls execution of task exceptions by, for example, defining or activating a task exception.
  • Cyclic handler function
    Controls the execution of a handler activated periodically.
  • Alarm handler function
    Controls the execution of a handler activated at the specified relative-time.
  • Overrun handler function
    Controls the execution of a handler activated when the specified time has been exceeded.
  • Extended service call function
    Renesas original functions are following:
    • Task event flags
      Makes use of task event flag state to synchronize tasks.

Kernel specifications

Specifications/Functions: Supports the following functions including uITRON4.0 spec-compliant standard profile.
・Service calls for dynamic object   creation(cre_???, acre_???) and   deletion(del_???)
・Mutex (TA_CEIL attribute only)
・Message buffer
・Variable-length memory pool
・Alarm handler
・Over handler
The following is the Renesas-specific functions
・Task-attached event flag
Scheduling types: Priority basis type / Event-driven type
Target CPU: SH-1, SH-2, SH2-DSP, SH-2A, SH2A-FPU
*FPU of the SH-2E is not supported.
Service call number: 148
(Count xxx_yyy plus ixxx_yyy as one)
Maximum object number: 1023 (Only the cycle handler and the alarm handler have 15 each)
A maximum value can be selected with the configurator
Maximum Priority number: 255, A maximum value can be selected with the configurator
(Time takes for a target task to be executed after the wup_tas is issued.):
1.1 microseconds (SH7206, 200MHz, cache enabled)
Kernel code size: From 5.5k bytes to 44k bytes
Kernel RAM usage per task: Data: 64 bytes
Stack: 140 bytes




Item Description Note
Kernel souce program Kernel source program Provided only with mass- production licenses which include source code.
Kernel library Kernel library for system building
Kernel library for DSP support
Kernel library for SH2A-FPU
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 Assembler and C languages
Configurator To setup construction parametesr -
Various sample programs CPU initialization routine assembler source
CPU initialization routine C source
Exception enter/exit processing assembler source
Section initialization processing C source
Section information definition file
Undefined interrupt detailed information acquisition process source
System down routine source
Timer driver source
Workspace for configuration HEW workspace for system building
Project file for separate linkage
Project file for whole linkage
Manual HI7000/4 series user's manual -



Processing Flow

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.