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Connecting AT91xx based GPS-Loggers to USB on Linux

The XAiOX iTrackU and Gisteq PhotoTrackr GPS loggers have an Atmel AT91xx ARM achitecture microcontroler with USB support. It is supported by the Linux usbserial driver.

If you own an Asus Eee-PC, please read this: http://wiki.eeeuser.com/howto:usbserial

To get it running on older systems you have to do two steps (you have to be root to do all this):

1. Activate the AT91xx support

As already said above the USB interface is supported by the Linux kernel module usbserial. But this part of the driver it is not activated by default. To activate it you have to add options to the kernel module. The vendor ID for Atmel seems to be always 0x3EB. The product ID depends on your device type. Plug the device in and find out the device ID:

lsusb | fgrep Atmel

The device ID for known devices is:

6125 for XAiOX iTrackU
6125 for Gisteq PhotoTrackr
6126 for Gisteq PhotoTrackr Lite

Please report new device IDs. See also Chapter "Troubleshooting" below.

So you have to tell the usbserial driver these device IDs. There are two different ways depending the usbserial driver is a module or is staticly linked into your kernel. As far as I know, most Linux distributions have usbserial.ko as a module.

Note for Ubuntu 9.04 (Jaunty Jackalope):
Only the early releases used a staticly linked driver (see here and here), but this was changed back to a module using the usual updates (sudo apt-get upgrade;sudo apt-get upgrade).

1.1 If you have usbserial as module, add the following line

options usbserial vendor=0x03EB product=0x6125 # for XAiOX iTrackU and Gisteq PhotoTrackr

or

options usbserial vendor=0x03EB product=0x6126 # for Gisteq PhotoTrackr Lite

using a text editor to the end of the file /etc/modprobe.d/options for Debian or Ubuntu pre 9.04 systems. For Ubuntu 9.04 Jaunty Jackalope (and later Ubuntu versions ?) simply as root copy atmel-usb.conf to /etc/modprobe.d/.

On other distributions this file could not exist. Then try /etc/modules.conf instead or find it out from the manual man modprobe.

Then type

depmod -a
update-modules

to tell the system, that someting changed with the kernel module configuration.

1.2 If you have usbserial linked to your kernel, add the following line

usbserial.vendor=0x03EB usbserial.product=0x6125 # for XAiOX iTrackU and Gisteq PhotoTrackr

or

usbserial.vendor=0x03EB usbserial.product=0x6126 # for Gisteq PhotoTrackr Lite

and reboot.

2. Load the driver (only if you have usbserial as a module)

The driver can loaded in two ways

always on system start by adding a line

usbserial

to the file /etc/modules using a text editor. The module will be loaded then always on system start using the options you added as described above. This should work on all current Linux distributions.

*** or ***
triggered by the plug USB cable in event using the udev framework (at least for current Debian and Ubuntu distributions). To do this you simply have to copy this 66-atmel-usb.rules to your /etc/udev/rules.d folder.

If the usbserial module is already loaded (because of a connected RS232-USB adapter cable or a USB connected mobile phone) the module has to reloaded to use the changes made.

rmmod usbserial
modprobe usbserial

This could fail because of other loaded modules which depend on usbserial. You have then to rmmod this modules too or simply start your system new.

Troubleshooting

If you come into trouble check all step by step (you have to be root to do all this):

Does your USB works on yous system at all ?
You should have successfully used an USB memory stick, an USB WLAN stick, an USB Bluetooth stick, an RS232-USB-adapter or something like this before you try the next steps.
Does the system recognizes the AT91xx USB devive ?
Type lsusb before and after you plugged in the cable. If your system does not know the lsusb command you have to install the package usbutils on Debian/Ubuntu. The output from lsusb should show a line like this if the device is plugged in:

Bus 004 Device 016: ID 03eb:6125 Atmel Corp.

The Bus and Device numbers depend on which plug you connect the device, but the ID should be exactly the same: 03eb:6125. If not please tell it the author of this page. Check the output of the dmesg command and the content of the system log to see what is going wrong.
Is the module usbserial already loaded ?
Type lsmod | fgrep usbserial and search a line beginning with usbserial like this:

usbserial 33448 2 ftdi_sio,pl2303

If it appears, the module is already loaded. We see too, that the module is currently used by two other modules: ftdi_sio and pl2303. This must not be so.

Skip next step if you did not got the line above. That means, the usbserial module was not loaded.
Can the module be unloaded ?
Type rmmod fdti_sio and rmmod pl2303 or whatever you find out above (or nothimg if usbserial was not used by any other module) and then rmmod usbserial. No answer means success.
Can the module loaded again ?
Type modprobe usbserial vendor=0x03EB product=0x6125. No answer means success. As you see we give the options you entered in the file /etc/modprobe.d/options as described above as an alternative directly on the command line. If this helps, check the enty in /etc/modprobe.d/options and check if this ist the right file for your system (man modprobe). Check the output of the dmesg command and the content of the system log to see what is going wrong.
Is there any USB tty device file ?
Type ls -l /dev/ttyUSB* and ls -l /dev/usb/tty/*. One of both commands should print out a line like

crw-rw---- 1 root dialout 188, 0 2007-10-07 17:08 /dev/ttyUSB0

and not No such file or directory. More than one line are ok too if you habe connected an RS232-USB adapter cable or your mobile phone.
Do you have rw permissions for the USB tty device file ?
In the example line above the group of the device is dialout (historical from modem devices). So your user has to be in the group dialout. Check this in the file /etc/group. There will be a line beginning with dialout on which you can see your user name too.

That is all. Now try to access the device using your application, here iTU4l.pl, which does the rest.

11.07.2009, itu4l⟨ΑΤ⟩schimmelnetz.de