SMBusb - Open-source USB SMBus interface

SMBusb is a cheap, versatile, open-source SMBus (and I2C) USB interface.


  • Based on the Cypress FX2LP dev-board shown above (available for ~$5 shipped on eBay)
  • Read/Write all standard SMBus transfer modes (byte, word, block)
  • Packet Error Checking (PEC) support
  • Arbitrary protocol functionality (allows for I2C or non-standard SMBus protocols)
  • Device and command discovery/probing
  • No extra components needed
  • Open source firmware and library
  • Multi-platform. (Tested on Linux and Windows)
  • Firmware is compiled into the library and loaded on-demand



  • Use the SCL/SDA/GND pins marked on the dev-board, NO external pull-up resistors necessary.
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