This demonstration board is a USB-to-serial communication conversion module using USB Peripheral function and serial communication functions (UART/I2C/SSU) with an R8C/3MK Group MCU.

Precautions for correct use

  • This demonstration board can operate only on a VBUS power supply. Do not supply power from an external serial communication device.
  • The power supply voltage is 3.3 V. This board does not support 5 V.
  • There are also terminals on the rear surface. They should not be in direct contact with a conductive material.


  • This demonstration board includes sample firmware for USB-to-UART conversion function in the MCU. You can use this function without developing firmware
  • This demonstration board has a preinstalled firmware downloader that works via USB. You can update firmware with no hassle
  • The upgraded firmware includes USB-to-I2C and USB-to SSU conversion functions and is provided free of charge
  • This demonstration board can operate on a VBUS supply (from USB Host)

Documentation & Downloads

Title Other Languages Type Format File Size Date
Application Notes & White Papers
USB-to-Serial Communication Conversion Demo Board R0K5R8C3MDU30BR Instruction Manual 日本語 Application Note PDF 994 KB
USB-to-Serial Communication Conversion Demo Board Download File 日本語 Software & Tools - Others ZIP 2.94 MB