Contents

Overview

The BrainStem USB Interface offers a USB-based connection to any standard RS-232 serial device.  This is accomplished in two layers.  The first layer manages the direct USB driver layer to connect to the Bridge chip used on the USB Interface board.  The second layer sits on top of the base layer and it provides a psueudo serial interface to you operating system layer.  This allows you to use standard serial calls on your computer and things get negotiated across USB to the TTL level signals that form the other end of this interface connector.  These signals conform to the Acroname Serial Interface Standard so they work with all BrainStem modules, the CMUCam2+, Wheel Commander, and any other conforming device. 

Host and Peripheral USB

USB is based on a tree topology with each root node being a USB host and each branch of the tree being a peripheral.  Common peripherals are handhelds, phones, iPods, and BrainStems.  Unfortunately, a host and peripheral are not the same and you cannot readily connect a handheld or iPod that uses USB to the BrainStem as they are both peripherals.  You need a host like a PC to negotiate the traffic on the bus so a iPod powered robot is not currently an easy proposition. 

Windows USB Serial Adapter Information

The Windows interface is quite easy to set up.  That being said, we still see people that are challenged by this configuration.  The basic steps for this interface are as follows:

Start without plugging in the USB device.  It won't break anything if you do (you probably did first, before reading these instructions) but it is easier if you don't.  Install the drivers found in the Acroname Download Center .  This driver is found under the category "Drivers" and the target "Win32". 

Be certain you get the proper driver where the part number on the back of your USB interface connector matches the driver file name.  These drivers are pretty straightforward.  It will seem like it installs twice as there are two layers and each needs to be installed. 

Next, you can plug in the interface connector and you should get some sort of happy sound and indication from the device manager that the device is recoginized and ready to use.  There are two things to check out at this point.  One is whether the little yellow light is lit on the connector.  This indicates that the connector is getting reliable power.  The second is to open your device manager to check that the hardware has been recoginized by Windows.  This is under your Control Panel's System Icon.  The System Properties show a tab named "Hardware".  Click on this and then click the "Device Manager" button.  You will get a screen that looks like this:

Make sure this device is present and doesn't show a yellow icon with a question mark which would indicate that there is a problem with the drivers or the connection. 

Now, the device is ready to use if you have gotten this far.  For the BrainStem or other devices, will need to figure out what the device ("COM" port in Windows speak) name is.  This can be done by getting the properties by right-clicking on the entry shown above in the device manager.  This will give you a property panel and you will want the "Port Settings" tab.  Click the Advanced Button and you can then change or learn what COM port you are using:

Digging deeper into the USB port configuration in Windows.

Be sure you configure your device to use the shown COM port or change the COM port to the one you need to use for your device.  Generally, it is safest to use an unused COM port below COM5, although if you know what you are doing, any COM port will work. 

Configuring Brainstem Applications in Windows

The final step is only relevant for BrainStem users.  You will want to make a file for each of our standard applications (like Console, Moto, and GP).  These files are all documented in the reference (just type ".config" in the find box on any website page including this one).  Each file is a plain text file and the case (capitalization) of the file name is just as important as the extension.  If either is wrong, the file will not work.  For instance, the console uses a file named "console.config".  This file must be placed in the aBinary directory.  If you downloaded the GP and Console applications into separate folders (we recommend you place them on top of one another in the same folder), you must make sure you have the file in the same aBinary directory as the executable you are trying to run (like GP.exe). 

Making sure Windows did not append a txt file extension.

The file contents are a couple of lines of text that again must be typed with the proper case to work.  Here is an example console.config file that specifies COM4 as the port for the Console application to use:

Spaces don't matter in the config files and you can comment out a line with the "#" character so this same file could written:

Configuring Brainstem Applications in MacOS X

The configuration procedure for the USB to serial devices has previously been covered in the article MacOS USB Tips .  The following procedure outlines the necessary steps to get the USB Serial Interface Connector to work with your system. 

Install the drivers found in the Acroname Download Center .  This driver is found under the category "Drivers" and the target "All".  Select the "MacOS X USB/Serial Drivers" download option.  Untar the downloaded file and double click it to expand the download into a Disk Image.  Follow the instructions in the installer and view the README.txt file if necessary. 

Follow the instructions at MacOS USB Tips .  The major difference will be the name of the USB device.  Here is an example console.config file for the S19-USB-SERIAL-INT adapter. 

Linux USB to Serial Adapter Information

The USB Serial Interface Connector has been tested sucessfully on a Fedora Core 3 install with a 2.6 kernel.  A Brainstem's heartbeat was observed using Minicom without having to install any additional drivers or do any modifications of the system to get things to work. 

Other Linux based systems are NOT supported directly by Acroname due to variety of kernels, OS versions, hardware, and religions. 

Conclusion

In general, you will need to load the drivers, set a known COM port, and create a 1-line text file with the proper name, extension, and contents.  That should be all you need to use the BrainStem modules with the USB Interface.  Once this work is done, you likely will not need to do it again as long as you use the modules on the same machine.  There are more notes on downloading the software in the Windows Downloading Tips . 

Revision History:

• 2007-11-07: Added a comment so users are sure they get the correct driver for the part number of the USB adapter they are using.

Related Links:

Acroname Serial Interface Standard

Tips on interfacing the BrainStem to a MacOS X USB hub

BrainStem - Hardware