Renesas mPD720231, Руководство пользователя

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μ
PD720231 4. USB Descriptor Information
R19UH0094EJ0100 Rev 1.00 Page 12 of 30
Mar 1, 2013
4.3
Configuration Descriptor (All speeds)
A configuration descriptor describes information about a specific device configuration. When the host
requests the configuration descriptor, all related interface and endpoint descriptors are returned.
Offset Field Size Value Description
0 bLength 1 09h Size of descriptor
1 bDescriptorType 1 02h Configuration descriptor type
2 wTotalLength 2 0079h Total length
4 bNumInterfaces 1 01h Number of interfaces supported by this configuration
5 bConfigurationValue 1 01h Number of this configuration
6 iConfiguration 1 00h Index of string descriptor describing configuration.
7 bmAttributes 1 C0h Configuration characteristics.
C0h: Self-powered
8 bMaxPower 1 12h (in
Super-
speed)
32h (in
High-/Full-
speed)
Maximum power consumption of the USB device from
the bus in this configuration when the device is fully
operational. Expressed in 2-mA units when the
device is operating in High/Full-speed mode and in 8-
mA units when operating in Super-speed mode.
4.4
Interface Descriptor
An interface descriptor describes a specific interface within a configuration. An interface descriptor is
returned as part of the configuration information returned by a GET_DESCRIPTOR Configuration request.
4.4.1
Interface descriptor for BOT mode (All speeds)
Offset Field Size Value Description
0 bLength 1 09h Size of descriptor
1 bDescriptorType 1 04h Interface descriptor type
2 bInterfaceNumber 1 00h Number of interface
3 bAlternateSetting 1 00h Value used to select alternate setting for the interface
identified in the prior field
4 bNumEndpoints 1 02h Number of endpoints used by this interface
5 bInterfaceClass 1 08h Class code: Mass Storage Class.
6 bInterfaceSubClass 1 06h or 02h SubClass Code: SCSI Transport or ATAPI
7 bInterfaceProtocol 1 50h Protocol Code: Bulk-Only Protocol
8 iInterface 1 00h Index of string descriptor describing interface