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:M3T-MR30/4 Real-time OS for M16C Series and R8C Family



  • Conformance with the µITRON4.0 Specification
    The design conforms with the µITRON4.0 Specification, which prescribes a representative OS architecture for embedded control.
  • ROM-based implementation
    The kernel is provided in library format. You can link only the functions you need at the time of system generation and minimize application software size.
  • Equipped with the configurator
    The configurator is equipped which makes the setup of OS construction parameters easier. Using the combination of GUI configurator and cfg8c configurator based command line lets you automatically generate start-up programs that rely on development products by just creating a simple definition file (configuration file), and so on. You can easily and reliably process parts specially suited to the product. [Learn More]
  • Interlinking with the High-performance Embedded Workshop IDE
    OS-embedded applications can be developed using common operations of the Renesas MCU toolchain.
  • Supported compiler: C/C++ Compiler Package for M16C Series and R8C Family [M3T-NC30WA]
  • Learn More

Release Information

Latest Ver.: V1.01.00
Released: Sep 16, 2011
Details of upgrade (See Tool News)
Operating Environment
Agreement Details

Target Devices


Additional Details


M3T-MR30/4 Real-time OS for M16C Series and R8C Family


Target MCU R8C Family
Max. number of tasks 255
Number of priority levels 255
Max. number of eventflags 255
Width of an eventflag 16 bits
Max. number of semaphores 255
Type of semaphores Counter type
Max. number of data queue 255
Data queue size 16 bits
Max. number of cyclic handler 255
Max. number of alarm handler 255
Number of service call 43
Kernel language Assembly language, C language
(Time takes for a target task to be executed after the wup_tas is issued.)
19 microseconds (20MHz)
Kernel code size Approximately 1.5K to 6.5K bytes
Kernel RAM usage per task Data: 11 bytes
Stack 8 bytes

Components of Evaluation License Package

Kernel library mr8c.lib
Kernel library source files Not included.
(* Included with Mass-production License  Package)
Configurator cfg8c
Utilities mr8ctbl
Default configuration file default.cfg
C interface library c8cmr.lib
C language include file itron.h, kernel.h, kernel_api.h, kernel_sysint.h
Sample start-up program [For NC30] crt0mr.a30
[For AS30] start.a30
Sample Section definition file [For NC30] c_sec.inc
[For AS30] asm_sec.inc
System RAM area definition database file sys_ram.inc
Table database file mrtable.tpl
Service call file for issuing service call isssys.mrc
Include database file mr8c.inc
MR8C/4 version file version
Sample program demo.c, smp.cfg

Components of Mass-production License Package

(1) With source code

  • Components of Evaluation License Package
  • Mass production rights (For details, see the License Agreement.)
  • MR8C/4 kernel libraries (mr8c.lib) source files

(2) No source code

  • Components of Evaluation License Package
  • Mass production rights (For details, see the License Agreement.)

Processing Flow