Device::USB::DevConfig - Access the device configuration returned by libusb.


Device-USB documentation Contained in the Device-USB distribution.

Index


Code Index:

Device::USB::DevConfig

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This class encapsulates a USB Device Configuration and the methods that object would support.

NAME

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Device::USB::DevConfig - Access the device configuration returned by libusb.

VERSION

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Version 0.12

SYNOPSIS

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Device::USB:DevConfig provides a Perl object for accessing a configuration of a USB device using the libusb library.

    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();

    my $cfg = $dev->config()->[0];
    print "Config:", $cfg->iConfiguration(), ": interface count: ",
       $cfg->nNumInterfaces(), "\n";

See USB specification for an explanation of the attributes of a configuration.

DESCRIPTION

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This module defines a Perl object that represents the data associated with a USB device's configuration. The object provides read-only access to the important data associated with the configuration.

METHODS

There are several accessor methods that return data from the configuration. Each is named after the field that they return. These accessors include:

wTotalLength

Returns the total length of the data returned for this configuration.

bNumInterfaces

Returns the number of interfaces supported by this configuration.

interfaces

Returns a list of lists of interface objects associated with this configuration. Each of the inner lists is a set of alternate versions of that interface.

bConfigurationValue

Returns the value passed to SetConfiguration to select this configuration.

iConfiguration

Returns the index of the string descriptor describing this configuration. The string can be retrieved using the method Device::USB::Device::get_string_simple.

bmAttributes

Returns a bitmap listing the attributes. The bits a number starting with the LSB as 0. Bit 6 is 1 if the device is self-powered. Bit 5 is 1 if the device supports Remote Wakeup.

MaxPower

Returns the Maximum power consumption in mA. This value is not in units of 2mA as in the spec, but in actual mA.

DIAGNOSTICS

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

DEPENDENCIES

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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

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

Houston Perl Mongers Group

BUGS

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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.

ACKNOWLEDGEMENTS

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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.

COPYRIGHT & LICENSE

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Device-USB documentation Contained in the Device-USB distribution.
package Device::USB::DevConfig;

require 5.006;
use warnings;
use strict;
use Carp;

our $VERSION=0.12;

# I need to build a lot of accessors
sub _make_descr_accessor
{
    my $name = shift;
    ## no critic (ProhibitStringyEval)

    return eval <<"EOE";
sub $name
        {
            my \$self = shift;
            return \$self->{$name};
        }
EOE
}

sub interfaces
{
    my $self = shift;
    return wantarray ? @{$self->{interfaces}} : $self->{interfaces};
}

_make_descr_accessor( 'wTotalLength' );
_make_descr_accessor( 'bNumInterfaces' );
_make_descr_accessor( 'bConfigurationValue' );
_make_descr_accessor( 'iConfiguration' );
_make_descr_accessor( 'bmAttributes' );
_make_descr_accessor( 'MaxPower' );


1;