RL78 Family Development Environment



The IDE (Integrated Development Environment) of the RL78 family MCU includes a plug-in that automatically generates codes for the timer and serial interface, thus allowing you to start development immediately. Also provided is a real-time OS with various middleware available on request. We provide general-purpose middleware products for self-programming of flash memory, encryption, and audio replay. We also provide special products, such as Bluetooth® Low Energy protocol stack for RL78/G1D, and Sub-GHz enabled communication stack for RL78/G1H.
For new products pertaining to the RL78/G23 groups or later, we provide Smart Configurator for combining software in ways that meet your needs. You can easily incorporate Renesas drivers into your system simply by importing the middleware and driver and specifying pin settings.


Combinations of Various Types of Software Support the Development of User Programs

By using the e² studio or CS+ IDE, you can configure software for the RL78 Family as user-code templates in combination with the software modules listed below.
You can focus on the development of your applications instead of manually creating drivers.

- User-code templates

Source code for initializing user programs, including the main() function and the making of clock settings, can be output as templates to which you can also add new code for the user system. You can create the user system by simply customizing the templates.

- Configured peripheral drivers

Peripheral drivers are available for import into user programs.
The peripheral drivers have been set up for the control of the peripheral modules of MCUs and include software for driving A/D converters, IIC, SPI, UART, timers, and PWM output.

- Realtime OS

In addition to the existing real-time OS for the RL78 family, you can import FreeRTOS from Amazon Web Services (AWS) into a user program. FreeRTOS is realtime OSes that are suitable for systems that require Internet connection.


The e² studio or CS+ IDE automatically generates the peripheral drivers.
An example of the steps to take in the IDE window to configure a user program in a short period of time is given below.

  1. Select the software modules you wish to use.
  2. Set up the software modules.
  3. Download the software modules to the RL78 MCU and start debugging.

The Code Generator generates code from the Smart Configurator. For details, refer to the following Web page for the Smart Configurator.
RL78 Smart Configurator


RL78 Family software feature image

Use Case

Individual software modules can be combined with other software modules and boards to configure a desired type of user program.
For example, you can configure a variety of systems as shown below.

- Using a timer in the RL78/G23 on the RL78/G23 Fast Prototyping Board to cause the LED to blink at regular intervals (basic program for initial evaluation)

Actual system
Software configuration


-Connecting a sensor on the RL78/G23 Fast Prototyping Board and collecting the values from the sensor

Actual system
Software configuration


- Connecting a USB-to-serial conversion chip on the RL78/G23 Fast Prototyping Board to enable UART communications between a PC and the RL78/G23 MCU

Actual system
Software configuration


- Visualization of Sensor Information on AWS using RL78/G23-128p Fast Prototyping Board and FreeRTOS

Actual system
Software configuration




Generation DriverCode GeneratorCode Generator Plug-inAutomatically generates control programs for peripheral modules (device driver programs). Included in the CS+ and e² studio integrated development environments (IDEs), enabling the creation of source code for control programs by configuring the user settings in a GUI.
RL78 Smart ConfiguratorRL78 Smart Configurator automatically generates initial-setting programs for MCUs. It provides a quick and smart way of combining and configuring software to meet your needs, such as by configuring peripheral pins and importing middleware and drivers.
DriverSerial MemoryI²C Serial EEPROM DriverA device driver for the RL78 Family I2C Bus Serial EEPROM R1EX24xxx Series, R1EV24xxx Series, and HN58X24xxx Series.
SPI Serial EEPROM DriverA device driver for the RL78 Family SPI Bus Serial EEPROM R1EX25xxx Series and HN58X25xxx Series.
SPI/QSPI Serial Flash Memory, QSPI Serial Phase Change Memory DriverA device driver for the RL78 Family SPI/QSPI Bus Serial Flash Memory and QSPI Bus Serial Phase Change Memory.
MiddlewareSensorSensor SoftwareThis software controls Renesas sensor products and acquires measurement data. It consists of a sensor middleware layer and an I2C communication middleware layer.The combination of these two layers makes it possible to develop applied products easily and quickly using Renesas sensor products, without being aware of the type of MCU or the control method of the communication interface.
USBUSB DriverThe device driver for USB communication using the RL78 MCU's built-in USB interface.
File SystemM3S-TFAT-TinyThe RL78 Family open source FAT file system.
Protocol StackBluetooth® low energy Protocol StackThe Bluetooth® Low Energy protocol stack for operation with the RL78/G1D is certified as compliant with Bluetooth v4.2.
Wi-SUN/Sub-GHzA solution is available for using the embedded Wi-SUN (Wireless Smart Utility Network) communications function of the RL78/G1H MCU.
Security / CipherCryptographic LibraryRenesas provides a cryptographic (RSA, AES and hash function) library for the RL78 Family. This strong cryptographic library is useful in developing systems for which security is essential.
DSP / FFTFFT LibraryThe frequency characteristics of input data can be measured by obtaining the FFT (Fast Fourier Transform). For example, by obtaining the FFT of audio data, you can measure the amplitudes (volumes) in each frequency band of which the sound consists.
Sound / VoiceSound Playback/Compression System (M3S-S2-Tiny)A small memory type sound playback system. Its original algorithm expands sound in ADPCM mode compactly at high speed. It can be used to add true sound output functionality to devices that previously only provided visual indications.
Self programming libraryCode Flash LibraryThis free-of-charge software library is for use with user programs that have to rewrite the contents of code flash memory (an EEPROM emulation library for code flash memory is also included).
Data Flash LibraryThis free-of-charge software library is for use with user programs that have to rewrite the contents of data flash memory (an EEPROM emulation library for data flash memory is also included).
OSITRON OSRL78V4 V2 Real-time OS for the RL78 FamilyA real-time operating system (real-time OS) that conforms to the μITRON4.0 specification, the predominant real-time OS for embedded systems. It is suited for an embedded system with real-time capability and multi-tasking functions.


Software Products from Partners

A wide variety of software products from Renesas partners is also available.
Renesas RL78 Partner Ecosystem Overview

Sample Code

Sample code for practical examples of the use of drivers and examples of the control of devices.
Sample Codes for RL78 Family


Type Title Date
Flyer PDF 149 KB 日本語
Brochure PDF 12.02 MB 日本語
Flyer PDF 386 KB 日本語
Flyer PDF 431 KB 日本語 , 简体中文
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