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Belcarra Overo USB TestDrive Setup
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Belcarra TestDrive

Overo Setup and Testing

Belcarra supports a testing environment for testing Networking over USB protocols. This paper will explain the Overo USB Device side software components.

This document, the second of a series, is an overview of the USB Device testing using Belcarra’s Overo USB TestDrive Environment, a Linux test system (available here) based on the Gumstix Overo board. The Overo board is a low cost hardware development system using Texas Instruments’ OMAP 3530 System On Chip (SOC) and supports USB 2.0 for both host and client implementations.


The TestDrive system can be used to test and evaluate various Networking over USB protocols and implementations:

Preparing to Install

This requires an SD card with at least 4GB of space.  A page at shows how to create a basic 2-partition SD card.  For our demo kit, follow the same procedure, but create three partitions. See Preparing a Micro-SD Memory Card for use with Gumstix COM for further detail.

Installation of the TestDrive Kit

The following is an example of how to install the kit.  We have made a few assumptions:

  1. On host machine create an empty directory (we’ll call it “extract” for now):

 mkdir extract

  1. cd extract
  2. mkdir p1 p2 p3
  3. Unmount partitions from wherever they are mounted and mount them on p1, p2, and p3. Here’s a sample sequence to achieve this:
  1. sudo umount /dev/sde[123] #You will see error messages if some or all of the partitions are not currently mounted
  2. sudo mount /dev/sde1 p1
  3. sudo mount /dev/sde2 p2
  4. sudo mount /dev/sde3 p3
  1. Write your local versions of MLO and u-boot to p1 (optional). They are available from here.  Note: MLO must be the first file copied onto extract/p1 due to a size restriction of the Overo’s boot loader.
  2. Extract the contents of the archive, using a command similar to the following:
  1. sudo tar xjf ../belcarra-gumstix-overo-kit-2011-03-17.tar.bz2
  1. Populate the third partition as follows
  1. cd p3;sudo unzip ../
  1. Wait for the SD card to finish writing (this may take a couple of minutes):
  1. sudo sync
  1. Unmount the volumes and clean up the directory
  1. cd ..
  2. sudo umount /dev/sde[123]
  3. rm -f *.zip

The TestDrive Environment

After preparing the SD card, use it to boot the Overo.  There are three facilities of note:

Belcarra Windows USBLAN Evaluation Driver

Belcarra’s USBLAN Evaluation Driver is available via Windows Update. It is available for use when a device using either of the following Vendor / Product ID’s is plugged into Windows.

  1. 15ec / d041 - enable the built-in DHCP service
  2. 15ec / d042 - disable the built-in DHCP service

Please note that the evaluation driver will only work for thirty minutes at a time.

Setting up EEM or ECM on the Overo

Using Belcarra modules -- Demo versions

When the Overo boots, a number of shell functions are available to set up common test requirements. There are 2 “Demo” USB Vendor/Product ID pairs:

For each of these pairs, an evaluation version of Belcarra USBLAN is available from Windows Update for either the EEM or ECM network protocol.  For Demo #1, the built-in DHCP feature of DHCP is activated. For Demo #2, the built-in DHCP feature is not active. See here for more information on USBLAN features, including the built-in DHCP server.

Note: the above modules first unload the  Gadget modules, if present (see below).  Also there is an optional argument, an IP address.

For instance



The IP address is optional.  In this case, the IP address may be set by the DHCP server (for Demo #1, not Demo #2 VIPD/PID).   Afterwards, if the IP address has not (yet) been set then there is a supplementary net command:

Using Belcarra modules -- general VID/PID

If you have your own version of Belcarra USBLAN with your own values of Vendor ID and Product ID, then you can set up EEM or ECM as follows. Here VID stands for your own vendor ID and PID for your own Product ID

Note: after using either of these modules, you must run BTCDOWN before the other functions (eem1, eem2, ecm1, ecm2) will work.

Testing using the Gadget modules

The following commands first unload the Belcarra modules if necessary.

All the commands have an identical format

command [-q] vid pid [ip]

Here command is one of the following: std-ecm std-eem std-ncm for Gadget ECM, Gadget EEM or Gadget NCM respectively.

The optional -q means quick meaning to proceed without user confirmation. Otherwise, the command will first summarize the proposed action before proceeding. The user can press y to proceed or any other key to abort the operation

vid pid are specified as follows:

For Demo #1 15ec d041

For Demo #2 15ec d042

After licensing your own copy of USBLAN, you can substitute your own values. This is convenient for testing USBLAN before your own device is ready for final testing.

ip is an optional IP address. After loading the modules, the system first delays a short time and then sets this IP address. If this value is omitted or is set to the special value then the command does not set the IP address, and instead relies on DHCP.


std-ecm -q 15ec d041 169.254.12  

Set up Gadget ECM using Demo #1 VID/PID values and set IP address Do not ask for user confirmation

std-ncm 15ec d042

        Set up Gadget NCM, do not set the IP address, using Demo #2  VID/PID values. Ask for user confirmation before proceeding.

Which mode is current?

To discover which modules are in use issue this command:


For Belcarra, the list will include network_if.

For Gadget the list will include g_ether or g_ncm (For Gadget the EEM protocol is supported as a part of the g_ether module, which imposes severe limitations on the Gadget implementation).

The gadget modules can be manually unloaded as follows:

rmmod g_ether musb_hdrc  (EEM or ECM)

rmmod g_ncm musb_hdrc (NCM only)

The Belcarra system is more complex and therefore BTCUNLOAD is provided to unload the Belcarra modules

Network testing

There are two major methods available for network benchmarking and stress testing

Mass Storage testing

Mass storage testing is done as follows

Additional  Documentation

Related Sites

Copyright ©2005-2013 Belcarra Technologies (2005) Corp.

Document Created: March 2011