Belcarra USB TestDrive

Belcarra supports an environment for testing USB Networking protocols. This paper, is the first in a series and will provide an overview of this environment which includes both USB Host and USB Device side software components.

Belcarra’s Overo USB TestDrive is a Linux based test system based on the Gumstix Overo board. The Overo board is a low cost hardware development system using a Texas Instruments OMAP series of System On Chip (SOC) technology. It supports USB 2.0 for both host and client implementations.


The TestDrive system can be used to test and evaluate various USB Networking protocols and implementations:
  • Gadget based network and filestorage function drivers
  • Belcarra based network and mass storage function drivers
  • Belcarra Windows USBLAN class driver
The USB TestDrive kit contains:
  • Overo ROOTFS
  • Compiled Linux kernel and modules
  • script to create an SD card to boot an Overo
Network test tools included:
  • wget / wput
  • iperf
  • apache
  • ping and pingall script
The following USB networking protocols are supported:
  • RNDIS *
  • CDC-NCM (2nd quarter 2011)
  • Mass Storage (Bulk only)
All of the CDC protocols can be easily tested against Windows Operating Systems (10, 8.1, and 7) using an evaluation version of Belcarra’s Windows USBLAN driver available from Windows Update.

The Overo kernel and root filesystem is setup with the following:
  • 2.6.34 Linux kernel (this is the first kernel to have proper CDC-EEM support in the Gadget subsystem)
  • Belcarra USB peripheral modules
  • Gadget modules
  • Network test tools installed and ready to use as soon as the system boots.
  • Gadget or Belcarra modules that can be loaded and unloaded for testing with a simple shell script
Setting USB options can be done by passing arguments to the module loading scripts:
  • Networking protocol - CDC-ECM, CDC-EEM, Mass Storage
  • USB Vendor and Product ID’s
Note that both Gadget and Belcarra’s USB stack implement Composite devices. Some variations of these can also be tested:
  • Network / Mass Storage
  • Network / Serial
  • Network / Serial / Mass Storage

Getting the Kit

The kit can be downloaded from the Belcarra USB TestDrive archive.

The Belcarra Linux kernel is available from github with the following:
git clone
NOTE: Belcarra’s Composite USB stack is available separately. Contact

Overo Setup and Testing Overview

Additional Documentation