Gadget Renesas

Linking Ideas and Electronics



GR-CITRUS tiny board enables easier to program with Ruby language. You can develop your Ruby code with "Rubic" on chrome app. Of course you can program like Arduino sketch on Renesas Web compiler and IDE for GR.
By connecting with WA-MIKAN that has ESP8266 module for Wi-Fi, you can prototype a system using Wi-Fi and micro SD card.

Renesas 32-bit RX63N Group MCU is on board.
Compatible pin array with Arduino Pro Mini.
-FULL product attached long pin socket for WA-MIKAN.
(The image describe normal type)
Wi-Fi module "ESP8266" and micro SD socket.
-FULL has a pin socket for GR-CITRUS connection
(The image describe full type)

Pin Map


Item Description
Microcontroller RX631(R5F5631FDDFP 100pin QFP)
Data flash 32KB
Main clock 96MHz (internal)
Sub clock 32.768kHz
Operating voltage 3.3V
Board function Reset Switch, 20 expanding pin, User LED 1

Boards Distributor

Under planning outside Japan.

Technical Support

Technical Information
Related Web Site


Schematic / Design


How to program

You can make a sketch on Web compiler and write a program like USB flash memory.
Also you can use IDE for GR for that.

Latest firmware (for running Ruby)

It is a link to GR-CITRUS's latest firmware for Ruby. To write the firmware, please press the reset button of GR-CITRUS and recognize it as USB memory, then copy the bin file.

GR-CITRUS Latest firmware (GitHub)

Project file for e2studio

Project file for sketching in Eclpse-based development environment e2studio. For downloading and installing e2studio please refer to the product page.

Click to download. Import the archive file (zip) as an existing workspace from the menu 'File' -> 'Import' in e2studio.