Device::USB(3pm)

NAME

Device::USB - Use libusb to access USB devices.

VERSION

Version 0.35

SYNOPSIS

Device::USB provides a Perl wrapper around the libusb library. This
supports Perl code controlling and accessing USB devices.

    use Device::USB;

    my $usb = Device::USB->new();
    my $dev = $usb->find_device( $VENDOR, $PRODUCT );

    printf "Device: %04X:%04X\n", $dev->idVendor(), $dev->idProduct();
    $dev->open();
    print "Manufactured by ", $dev->manufacturer(), "\n",
          " Product: ", $dev->product(), "\n";

    $dev->set_configuration( $CFG );
    $dev->control_msg( @params );
    ...

See the libusb manual for more information about most of the methods.
The functionality is generally the same as the libusb function whose
name is the method name prepended with "usb_".

DESCRIPTION

This module provides a Perl interface to the C library libusb. This
library supports a relatively full set of functionality to access a USB device. In addition to the libusb, functioality, Device::USB provides a few convenience features that are intended to produce a more Perl-ish
interface.

These features include:

o Using the library initializes it, no need to call the underlying: usb_init function.
o Object interface reduces namespace pollution and provides a better: interface to the library.
o The find_device method finds the device associated with a vendor id: and product id and creates an appropriate Device::USB::Device
object to manipulate the USB device.
o Object interfaces to the bus and device data structures allowing: read access to information about each.

Device::USB

This class provides an interface to the non-bus and non-device specific functions of the libusb library. In particular, it provides interfaces to find busses and devices. It also provides convenience methods that
simplify some of the tasks above.
CONSTANTS: This class provides a set of constants for the defined device classes. The constants defined at this time are:; o CLASS_PER_INSTANCE; o CLASS_AUDIO; o CLASS_COMM; o CLASS_HID; o CLASS_PRINTER; o CLASS_MASS_STORAGE; o CLASS_HUB; o CLASS_DATA; o CLASS_VENDOR_SPEC
FUNCTIONS: new Create a new Device::USB object for accessing the library.; debug_mode
This class method enables low-level debugging messages from the
library interface code.

level
0 disables debugging, 1 enables some debug messages, and 2
enables verbose debug messages

Any other values are forced to the nearest endpoint.
find_busses: Returns the number of changes since previous call to the function: the number of busses added or removed.
find_devices: Returns the number of changes since previous call to the function: the number of devices added or removed. Should be called after
find_busses.
find_device: Find a particular USB device based on the vendor and product ids.
If more than one device has the same product id from the same
vendor, the first one found is returned.; vendor
the vendor id; product
product id for that vendor; returns a device reference or undef if none was found.
find_device_if: Find a particular USB device based on the supplied predicate
coderef. If more than one device would satisfy the predicate, the
first one found is returned.; pred
the predicate used to select a device; returns a device reference or undef if none was found.
list_devices: Find all devices matching a vendor id and optional product id. If
called with no parameters, returns a list of all devices. If no
product id is given, returns all devices found with the supplied
vendor id. If a product id is given, returns all devices matching
both the vendor id and product id.; vendor
the optional vendor id; product
optional product id for that vendor; returns a list of devices matching the supplied criteria or a
reference to that array in scalar context
list_devices_if: This method provides a more flexible interface for finding devices. It takes a single coderef parameter that is used to test each
discovered device. If the coderef returns a true value, the device is returned in the list of matching devices, otherwise it is not.; pred
coderef to test devices.; For example,

my @devices = $usb->list_devices_if(
sub { Device::USB::CLASS_HUB == $_->bDeviceClass() }

);; Returns all USB hubs found. The device to test is available to the coderef in the $_ variable for simplicity.
list_busses: Return the complete list of information after finding busses and
devices.; By using this function, you do not need to do the find_* calls
yourself.; returns a reference to an array of busses.
get_busses: Return the complete list of information after finding busses and
devices.; Before calling this function, remember to call find_busses and
find_devices.; returns a reference to an array of busses.

DIAGNOSTICS

This is an explanation of the diagnostic and error messages this module can generate.

DEPENDENCIES

This module depends on the Carp, Inline and Inline::C modules, as well as the strict and warnings pragmas. Obviously, libusb must be available since that is the entire reason for the module's existence.

AUTHOR

G. Wade Johnson (wade at anomaly dot org) Paul Archer (paul at
paularcher dot org)

Houston Perl Mongers Group

Original author: David Davis

BUGS

Please report any bugs or feature requests to
"bug-device-usb@rt.cpan.org", or through the web interface at
<http://rt.cpan.org/NoAuth/ReportBug.html?Device::USB>. I will be
notified, and then you'll automatically be notified of progress on your bug as I make changes.

FOR MORE INFORMATION

The project is hosted at Google Code
<http://code.google.com/p/perl-device-usb/>. More information on the
project, including installation help is available on the Wiki.

LIMITATIONS

So far, this module has only been tested on Linux. It should work on
any OS that supports the libusb library. Several people have reported
problems compiling the module on Windows. In theory, it should be
possible to make the library work with LibUsb-Win32
<http://libusb-win32.sourceforge.net/>. Without access to a Windows
development system, I can't make those changes.

The Interfaces and Endpoints are not yet proper objects. The code to
extract this information is not yet written.

ACKNOWLEDGEMENTS

Thanks go to various members of the Houston Perl Mongers group for
input on the module. But thanks mostly go to Paul Archer who proposed
the project and helped with the development.

Thanks to Josep MonA~Xs Teixidor for fixing the "bInterfaceClass" bug.

Thanks to Mike McCauley for support of "usb_get_driver_np" and
"usb_detach_kernel_driver_np".

Thanks to Vadim Mikhailov for fixing a compile problem with VC6 on
Windows and then chipping in again for VS 2005 on Windows, and yet
again to fix warnings on C99-compliant compilers.

Thanks to John R. Hogheruis for information about modifying the Inline parameters for compiling with Strawberry Perl on Windows.

Thanks to Tony Shadwick for helping me resolve a problem with bulk_read and interrupt_read.

COPYRIGHT & LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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