How to use USB virtual COM port


GR-SAKURA USB Virtual Serial Comm Port Example
To use a virtual serial port, you must use the dedicated driver "GRSAKURA.inf" for Port (COM and LPT).
The USB driver "GRSAKURA.inf" selects COM4: がじぇっとルネサス SAKURA (COM4).

Original of this example:

GR-SAKURA COM Driver Location:

#include <rxduino.h>
int count;
void setup() {
    Serial.begin(38400); // opens a virtual serial port. the baud rate parameter does nothing.
    pinMode(PIN_LED3, OUTPUT);

void loop() {
    if(Serial.available()) {                 // If any key is hit,
        digitalWrite(PIN_LED3, ++count & 1); // LED D4 turns on.


  • Hi!

    I can't find the driver on this location :(

  • In reply to matthias.kovarik:

    I think, it's a bit tricky as Rulz seems to select your "default" language, which is English.

    Please try the following:

    1. click on language selector in the the upper right corner and select Japanese ( 日本語 )

    Then the Japan Rulz should come up with the URL:

    2. now just paste the URL above into the browser. You can either use the issue URL and you should find a link on that page in the comments if you scroll down, or just paste the URL for the ZIP directly into the browser.

    I hope, this works also for you as it worked for me.

    By the way: it seems that the USB will not be installed every time at COM4. On my laptop it was using COM6, on my desktop it was using COM9.

    The best way to find out is to take a look to the Device Manager under Windows. It tells you, which COM port is used for the GR-Sakura device.

    hope that helps.

  • In reply to Juergen Zimmer:

    Thank you! It works! (COM6)

  • In reply to matthias.kovarik:

    Click on the Files menu (on left side of this page).

  • In reply to icserny:

    Istvan, and whoever add the file, many thanks indeed!