This is the English translation of following Japanese Rulz page:

This guide is provided for first-time users of GR-KURUMI board and explains how to program the board to make the LED on Kurumi's hair clip flash. By the way, Kurumi is a popular girl's name in Japan and actually means "walnut."

To follow these hands-on instructions, you need the following gadgets. If you don't have a so called "single-line pin header," metal paperclips work as well. 

0. Soldering

To connect GR-KURUMI to your PC, you need to solder a 6-pin single-line header to GR-KURUMI.  Please check the picture below to confirm where to put the header on the board. An angled pin header looks very slick and is quite convenient.   If you don't have a header, try using paperclips. Nip the paperclips into straight wires and insert them in the holes on the board.

1. Start coding

There are three ways to write code for GR-KURUMI:

  1. Web Compiler --- this is what we use in this description 
  2. IDE for GR --- it's a Java based desk top app like Arduino IDE
  3. e2studio --- a professional IDE offered by Renesas

To use the Web Compiler, you need to log in to Gadget Renesas site. "Guest Log In" is a trial entry that doesn't require register for this site.

Basic operations of the Web compiler can be found in the Rulz's posting "How to use Web Compiler".

2. Create a new project

You can create a new project by clicking the '+' icon shown below. An entry from "Guest Log In" lets you start a new project from scratch without user registration.  

Select an appropriate template, such as, where xxx indicates the version. Don't select a version of a GR-SAKURA sketch since you are using a GR-KURUMI board in this guide. Please note that the project name field does not allow use of any 2-byte characters like Japanese.

3. Displaying your sketch

Selecting the "Create Project" brings you to the Web Compiler IDE window. Click "gr_sketch.cpp" file under the explore menu.  The source code of the file will appear in the right window. This is the sample code that will drive the LED on Kurumi's hair pin.

4. Build the code

Since the code shown on the screen is a working sample, you don't need to debug the code. To build the code, click the "Execute Build" icon on the right navigation menu shown below.  This should show you  "The Compilation Is Complete" pop-up.


When the build is OK, the pop-up screen shows "Make process completed" at the bottom of screen.  Then click the close button.

5. Download the sketch

When the build is successfully completed, Web Compiler creates binary file "kurumi_sketch.bin" under the .CPP file shown below. Move the mouse onto the bin file and click the right click -  that shows the pop-up menu below. Then click "Download" menu.  We will use this bin file in Step 10.

6. Download Kurumi Writer

The next step is to download "Kurumi Writer," which is a PC (or MAC) application program that burns the kurumi_sketch.bin file in the flash memory on the GR-KURUMI MCU. Click the gr_writer folder on the explore menu to see more lists. Move your mouse on either or, depending on your computer. Then right click with your mouse to show the download menu on the pop-up. When you click the download menu, the kurumi_sketch.bin file will be downloaded to the destination folder you specify. Next, unzip the file.  We will use this file in Step 10.

7. USB driver for FTDI

Here, we will download the USB driver from the website of FTDI, © Future Technology Devices International Ltd. Make sure you download the proper version which matches to your computer.

Then unzip the the downloaded file which we we will use in Step 8.  Please be patient...your Kurumi board will be up and running in few more  steps!  FTDI url:

8. Connect GR-KURUMI

First, connect the GR-KURUMI board to the FTDI module shown below. Make sure both boards are facing up.  Then plug the opposite end of the USB cable into the FTDI module and PC. The red LED will turn on when the connection is right. After the connection is made, have your computer recognize the driver which you downloaded in Step 7.

We are using a Windows7 PC, so we manually specified folder "CDM 2.08.28 WHQL Certified" with "include subfolder" option during the plug & play initiation process.  This was the quickest way to  have the  PC recognize the driver.

9. Execute Kurumi Writer

Please execute the Kurumi Writer you downloaded in Step 6.

10. Configure Kurumi Writer

You need to set up the following menus.

  • Serial Port: USB Serial Port (COM ** )  (** is the number KURUMI board is assigned on your PC.)
  • Baud Rate: 500,000 bps (112,500 bps is fine too).
  • File: Select file kurumi_sketch.bin you downloaded in Step 5.

11. Flashing

Push Write.  The specified file will be programmed in the flash memory on the GR-KURUMI MCU. If you are using paperclips for the connection, the connection may be loose. Try tilting the kurumi board with your fingers, as shown below.