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To operate with a DS9490 USB to 1-wire adaptor, the driver entry in the devices
file should be set to USB.
Equivalently, you may type this into the entry in the devices dialogue.
If you have more than one DS9409 attached, you may tell Oww which one
to use by adding a number, e.g. USB:0 for the first adaptor.
As with any other node in the file system, a USB device has a set of permissions associated with it. Typically these will not allow access by ordinary users. This means that by default, typically only root will be able to run Oww using a USB adaptor. Actually this applies to serial ports too, so you may have had to add your users to a group allowing access.
You could simply change the USB device permissions manually, but there is a better way.
Hot-plugging of USB devices is now handled by udev.
The is capable of changing permissions, loading modules, etc, according to
rules found (typically) in /etc/udev/rules.d.
By inserting a new rule you can make udev set appropriate permissions for any DS9490R devices
automatically. Here is an example rule:
################################################################
# udev rules file for oww
# From rules by Jonathan Hudson
SUBSYSTEM!="usb_device", ACTION!="add", GOTO="oww_rules_end"
# DS2940
SYSFS{idVendor}=="04fa", SYSFS{idProduct}=="2490", GROUP="oww", MODE="0664"
LABEL="oww_rules_end"
################################################################
This rule checks for a USB device with the appropriate Vendor and Product tags,
assigns it to the Oww group
(you'll need to create an Oww group – use groupadd or your system's
group administration function), and gives group read/write permission.
Save it into the rules.d directory, or symlink it.
I call mine 56-oww.rules – the number is to get it in the
right order of execution, so that its rules don't get overidden by a later set.
You may need to experiment.
So long as Oww is run by a member of the Oww group (or root) it will enjoy full access to the DS9490R.
There have been several kernel modules written for the DS9490R. These are of no use to Oww, since it talks directly to the device through libusb. You therefore need to ensure none of these modules get loaded. You can do this by black-listing them in modprobe.conf or modprobe.conf.local (if you have it):
blacklist ds9490r blacklist ds2490 blacklist wire
If one of these modules was already loaded, remove it with modprobe -r.
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