Overview
Description
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
Features
- 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
Downloads
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| Type | Title | Date |
| Upgrade - OS | High-performance Embedded Workshop Real-Time OS Aware Debugging Upgrade module
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| Upgrade - OS | Real-time OS for R8C Family MR8C/4 V.1.01 Release 00 (Evaluation License) Upgrade
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| Upgrade - OS | Real-time OS for R8C Family MR8C/4 V.1.01 Release 00 (Mass-production License/No source code) Upgrade
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| Upgrade - OS | Real-time OS for R8C Family MR8C/4 V.1.01 Release 00 (Mass-production License/With source code) Upgrade
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4 items
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Documentation
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| Type | Title | Date |
| Release Note | PDF 237 KB 日本語 | |
| Tool News - Note | PDF 204 KB 日本語 | |
| Manual - Development Tools | PDF 1.07 MB 日本語 | |
| Tool News - Release | PDF 202 KB 日本語 | |
| Application Note |
PDF
695 KB
AI-generated Summary:
Interrupts enable embedded systems to handle time-critical tasks by signaling the processor to pause current operations and address urgent events. There are hardware and software interrupts, with hardware interrupts further divided into special and peripheral I/O types. The R8C family uses two interrupt vector tables: fixed and relocatable, which store interrupt service routines and their properties. Interrupt priority levels allow nested interrupts, and interrupts can be maskable or non-maskable, with NMIs reserved for critical system events.
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| Application Note |
PDF
126 KB
AI-generated Summary:
The system timer in MR8C/4 tracks elapsed time in an RTOS by generating periodic interrupts, incrementing a tick counter. The timer's resolution depends on application needs, hardware limitations, and counter storage. MR8C/4 uses a 6-byte counter allowing up to 8925 years of tick counting at 1ms resolution. Hardware timer inaccuracies require adjustments to ensure minimum delay durations. Users configure the system timer by selecting hardware timers, setting interrupt priorities, and defining interrupt vectors. The system timer manages time-based functions and is optional if no time management is used.
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| Application Note |
PDF
938 KB
AI-generated Summary:
MR8C/4 provides two types of time event handlers: cyclic handlers for repetitive events at fixed intervals, and alarm handlers for one-shot events at specified times. These handlers operate independently from tasks, executing in non-task contexts with priority between interrupts and dispatchers. Time event handlers must be statically created in configuration files and require the CPU to be unlocked for activation. Accuracy depends on system timer resolution, with R8C devices supporting up to 1 ms resolution. Cyclic handlers can be used to trigger tasks periodically without reprogramming timers.
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| Application Note |
PDF
750 KB
日本語
AI-generated Summary:
Real-time OS aware debugging supports various real-time operating systems including HI7200/MP, ThreadX, uC/OS-II, and TOPPERS variants. It operates within High-performance Embedded Workshop on Windows platforms and integrates with SuperH Family RISC engine simulators/debuggers. The document details environment setup, program downloading, OS definition selection, task state monitoring, execution history, and timing display functions.
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| Guide | PDF 371 KB 日本語 | |
| Application Note |
PDF
897 KB
日本語
, 简体中文
AI-generated Summary:
This guide explains how to create a workspace for MR8C/4 RTOS on R8C Family MCUs. It covers software preparation, including installing the M3T-NC30WA compiler package version 5.45 or higher, opening and configuring the workspace, and downloading programs using the E8a Emulator. The document provides step-by-step instructions with visual aids to facilitate user understanding and efficient setup.
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| Application Note |
PDF
469 KB
简体中文
AI-generated Summary:
Debugging with MR8C/4 using MR Window in High-performance Embedded Workshop streamlines application development by providing a graphical interface to monitor RTOS resources and error codes. The process involves identifying errors, interpreting MR Window data, and creating system down routines to locate faults. Practical exercises and sample programs enhance users' debugging skills, supported by detailed guidance on setup, techniques, and troubleshooting.
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| Application Note |
PDF
801 KB
AI-generated Summary:
Real-Time Operating Systems (RTOS) enable multitasking in embedded systems by providing timely and logically correct responses to events. RTOS combines real-time requirements with operating system features such as multitasking, synchronization, interrupt handling, and resource management. This document explains RTOS concepts, architecture, and selection criteria, focusing on their application in the R8C microcontroller family and highlighting their deterministic timing and efficient resource use.
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| Application Note |
PDF
583 KB
简体中文
AI-generated Summary:
This document explains how to calculate the user stack and system stack sizes for the R8C Family MCUs. It details the importance of allocating appropriate stack memory to prevent wastage and stack overflows. The user stack is assigned per task, representing worst-case memory usage during runtime, while the system stack is used during service call execution. Both stacks reside in internal RAM, and the document provides methods and examples for computing their sizes using configurator files and utilities.
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| Application Note |
PDF
760 KB
AI-generated Summary:
MR8C/4 is a preemptive priority-based RTOS designed for embedded applications using the R8C family MCU. Implementing MR8C/4 requires careful task partitioning, prioritization, and interrupt management to ensure real-time responsiveness. The RTOS increases memory usage due to additional code and task stacks, so memory allocation must be optimized. Proper implementation also helps reduce power consumption by enabling efficient CPU usage and minimizing memory waste.
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| Application Note |
PDF
152 KB
日本語
AI-generated Summary:
The MR8C/4 excludes service calls with timeout features to minimize memory usage. This document explains a workaround to implement timeout functionality by forcibly releasing tasks from the WAITING state using a timer. It details the removal of timeout-enabled service calls like tslp_tsk, twai_sem, and others, and illustrates how to apply the workaround method, particularly for the wai_sem service call, using a sample program.
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| Application Note |
PDF
325 KB
日本語
AI-generated Summary:
The document explains how to replace the Mailbox module, excluded in MR8C/4, with the Data Queue module for inter-task communication in R8C family MCUs. It compares the functionalities of Mailbox and Data Queue, highlighting that Mailbox manages message queues and wait queues for synchronization, while Data Queue handles one-word data elements with send and receive wait queues. Step-by-step guidance for converting Mailbox usage to Data Queue is provided.
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| Tool News - Release | PDF 195 KB 日本語 | |
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Additional Details
Successor
M3T-MR30/4 Real-time OS for M16C Series and R8C Family
Specifications
| Target MCU | R8C Family |
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| 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 |
| Performance (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 |
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| 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
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