Gadget Renesas

Linking Ideas and Electronics



The tiny GR-CITRUS board enables easier programming with Ruby language. You can develop Ruby code with "Rubic" on a Chrome app. Of course you can program Arduino-like sketches on the Renesas Web compiler and IDE for GR.
By connecting with WA-MIKAN that has an 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 version comes with long pin sockets for WA-MIKAN connection.
(Photo shows normal version, which has no pin header.)
Wi-Fi module "ESP8266" and micro SD socket.
-FULL version comes with pin sockets for GR-CITRUS connection
(Photo shows -FULL version, which comes with pin sockets.)

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


Sketch reference (Under preparation)

Create and Write a Program

Latest Firmware (to run Ruby)

This link provides the latest version of firmware for GR-CITRUS Ruby. To write the firmware to GR-CITRUS, press the reset button on the GR-CITRUS board, wait for it to be recognized as USB memory, and copy the bin file.

How to program

Create sketches on the Web compiler and write programs to GR-CITRUS as if it were a USB flash memory. IDE for GR can also be used to do the same processes.