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RL78 Family Software & Tools

Development Environment for RL78 Family


We provide you with an easy-to-use, scalable development environment and comprehensive support services for all of your development needs.

Renesas Electronics supports all aspects of application development for the RL78 family with products such as the integrated development environments e² studio and CS+, real-time operating systems, and programming tools. CS+ makes the full range of tasks related to coding, building, and debugging software straightforward and intuitive, dramatically reducing the time required for development.


  • A free evaluation version is also available for the building tools and the flash programming software.
  • A tool lineup differs depending on the product group of the RL78 family.



RL78 Family Development Tool Lineup


MCU Real-time OS Software Tools Emulators (Note7) Programming Tools
On-chip debugging emulator Full-spec emulator Programmer (Note2)
RL78 - RL78 Family C Compiler Package (without IDE) (Note1)

E2 emulator Lite

E1 emulator (Note6)


E2 emulator Lite (Note4)

E1 emulator (Note4, 6)

PG-FP5 (Note3)

RI78V4(V2) C Compiler and IDE for RL78 Family (Note5)
RI78V4(V1) C Compiler and IDE for RL78, 78K0R, 78K0 (Note5)


  1. IDE e² studio, compiler, simulator, and emulator debugger are not included. It can be used together with e² studio (you need to install e² studio separately).
  2. This is a programmer for flash MCUs from Renesas. For details about which programmers can be used with each MCU and the programmer specifications, see here.
  3. Used together with a programming GUI (provided free of charge).
  4. Used together with the programming software Renesas Flash Programmer (a free evaluation version is available).
  5. The IDE is CS+.
  6. The E20 emulator may be used on CS+ as well, but the supported debugging functions are equivalent to those of the E1.
  7. For details about which emulators can be used with each MCU and emulator specifications, see here.
    The emulator that can be used might differ depending on the MCU Part Name.


CS+ is not generally promoted in the U.S. and Europe. For customers in the U.S. and Europe who are interested in CS+, please contact our regional marketing departments for details.



Integrated Development Environment


Integrated development environments—powerful and comprehensive support for developing embedded systems


Renesas integrated development environments provide powerful support for developing applications to run on devices of the RL78 family.




This product brings together in a single package all the basic software tools needed for software development, from coding through building and debugging. There is also a feature that displays information on variables, functions, etc., in an easy-to-understand format. A full selection of tutorials is available, allowing even beginners to get started using this integrated development environment right away.


[Note] CS+ is not generally promoted in the U.S. and Europe. For customers in the U.S. and Europe who are interested in CS+, please contact our regional marketing departments for details.


Get up and running quickly: Starter kit


Want to start evaluating the RL78 right away? The Renesas Starter Kit is just what you need. It brings together in a single package all the development tools needed for microcontroller evaluation and initial implementation. The control signals from the microcontroller are output to the expansion board interface of the CPU board, allowing connection to the target system under development for easy debugging.


〈Components of Renesas Starter Kit for RL78〉


  • CPU board mounted with RL78
  • E1 on-chip debugging emulator
  • Evaluation version of Renesas integrated development environment (includes coding tool, emulator debugger, etc.)
  • Evaluation version of Renesas Flash Programmer flash programming software



<Transition guide>
For customers making the switch from the High-performance Embedded Workshop to CS+, we provide a transition guide covering differences in functionality and operations between the High-performance Embedded Workshop and CS+, and procedures for the transition. CS+ is an all-in-one package designed as an easy-to-use integrated development environment with a GUI-based interface and extensive pop-up menus. Nevertheless, its operation may seem unfamiliar to users accustomed to the High-performance Embedded Workshop so such users may have difficulty locating the functions they need. The transition guide is designed to help users avoid such inconveniences as far as is possible.
Migration to CubeSuite+ Integrated Development Environment for RL78 Family (On-chip Debug) - Migration from R8C, M16C to RL78
Migration to CubeSuite+ Integrated Development Environment for RL78 Family (On-chip Debug) - Migration from H8, H8S, H8SX to RL78



Starter Kits

[e² studio]


This product is suitable for the users who are conversant with the Eclipse environment and for those who want an environment for collaborative development with other users of the e² studio, including those at distant locations. Since this product works with compilers, code generators,simulators, and emulators for Renesas microcontrollers, you can use it for coding, building, and debugging for our devices, as well as using the general plug-in features that have evolved with the open-source Eclipse IDE.


CPU Boards

Testing CPU board


This target board is for testing RL78 microcontroller applications using the E1 on-chip debugging emulator (sold separately). It can be used for testing at all stages, from software development though actual system operation. All pins of the microcontroller are assigned to peripheral port connectors, making it possible to build evaluation circuits using commercially available universal wiring boards.



Real-time OS

Real-time OS for RL78 Family [RI78V4]


Enabling embedded systems with a high-quality real-time multitasking environment

  • Conformance with uITRON 4.0, an industry standard
  • Compact design suitable for ROM storage
  • Full complement of service calls
  • Excellent real-time performance (interrupt response time, task switching time)
  • Support for convenient functions when used in conjunction with the CS+ integrated development environment
    (automatic setting of options required to build the OS, display of the state of objects managed by the OS such as tasks and semaphores, graphical display of task operation history and service call issue history)



  • Extensive lineup for RL78 applications, including audio file system, and memory drivers
  • Common interface design with flexible supports for the entire RL78 family
  • Sample programs included; highly efficient design process for less time to product completion


〈RL78 family middleware lineup〉


Signal Processing / Numerical Libraries


File System

Memory Drivers

  • SPI mode MultiMediaCard Driver
  • SPI Serial Flash memory Driver
  • SPI Single Master Driver
  • Renesas SPI Serial EEPROM Driver
  • Renesas I2C Serial EEPROM Driver 1
  • I2C Single Master Driver 1

Note: 1. Under development or planning



Debugging Tools


Three approaches to debugging
Three approaches to the debugging environment are available for your development needs.


1.Debugging on a PC


[Simulator for CS+ of RL78 Family, 78K0R and 78K0]

  • Learn more about this product
  • Simulator enabling source-level debugging of applications in the CS+ integrated development environment before the target system exists
  • Rich break functions and coverage measurement functions
  • Ability to evaluate software modules in a manner very similar to evaluation on the actual device
  • Intuitive graphical user interface (GUI) operability makes your debugging environment highly user-friendly.




2.Debugging with basic functions


[E2 emulator Lite or E1 On-Chip Debugging Emulators]

  • Simple to connect. Allows debugging via a connection to the RL78 mounted in the system under development.
  • Can also be used with other Renesas Electronics microcontrollers.
  • USB bus powered. No external power supply required.
  • Also functions as a flash programmer.
  • Environmentally friendly. All materials, from components to packaging, are RoHS compliant.


E2 emulator Lite

Compatible with E1 emulator and more economical price. Suitable for the whole range from professional development to hobbyist projects and education.



E1 Emulator

This emulator delivers basic debugging capabilities at a low price and supports on-chip trace functionality.



  1. The E20 emulator may be used on CS+ as well, but the supported debugging functions are equivalent to those of the E1 emulator.


3.Debugging with high-level functions



A high-performance full-spec emulator with highly advanced functions.

  • Trace with time-tag function.
  • Provides access via a GUI to more powerful debugging capabilities, including a duration measurement function and coverage function.





Flash Programming Tools


Three approaches to programming
Three approaches to the programming environment are available to meet specific development goals and conditions.


1.Programming controlled by a PC

Flash programming software

Renesas Flash Programmer



2.Programming controlled by a PC or stand-alone programming

  • Flash programmer





3.Ordering pre-programmed ROM (growing number of products supported) (Note1)



Pre-programmed flash memory products from Renesas Electronics



  1. For more information, refer to this page.




Solutions From Partner Vendors


A wide variety of products for the RL78 family, such as compilers and programmers, are available from partner tool vendors. These products enable the RL78 family to be used in an even broader range of applications.



Third Party Tools


IAR Embedded Workbench for RL78 (EWRL78)
Full C and C++ support, C-SPY -- debugger, and instruction simulator
Real-time operating system for RL78
Download CMX-RTX RL78 Evaluation RTOS
μC/OS-II and μC/OS-III
Real-time operating system for RL78
Segger embOS
Segger logo Real-time operating system for RL78
FreeRTOS logo Real-time operating system for RL78