12-28
MCF5272 User’s Manual
Register Description and Programming Model
words and longwords. The user must make sure that any word
or longword fields are stored in the correct byte order.
A device may support multiple configurations. Within any one configuration, the device
may support multiple interfaces. An interface consists of a set of endpoints that presents to
the host a single feature or function of the device. An interface within a configuration may
have alternate settings that redefine the characteristics of the associated endpoints. All
devices must provide a device descriptor and at least one configuration, interface and
endpoint descriptor. Each configuration must have at least one interface and one endpoint
descriptor. Only one configuration is effective at any time, but several interfaces and their
related endpoints may be operational at the same time. Only one setting for a particular
interface is effective at any time.
12.3.3.2 USB Device Configuration Example
The example descriptor structure in Figure 12-23 shows a device with three different
configurations. Refer to Chapter 9 of the USB Specification for information on the contents
of each descriptor.
Figure 12-23. Example USB Configuration Descriptor Structure
This example is described in the configuration RAM sequence shown below. The device
descriptor begins at address MBAR + 0x1400. Each descriptor must immediately follow
the previous descriptor without any empty locations between them.
1. Device Descriptor
2. Configuration #1 Descriptor
3. Interface #0 Descriptor
4. Endpoint #1 Descriptor
5. Endpoint #2 Descriptor
Endpoint #2
Descriptor
Endpoint #1
Descriptor
Endpoint #1
Descriptor
Endpoint #3
Descriptor
Endpoint #2
Descriptor
Endpoint #1
Descriptor
Interface #0
Descriptor
Interface #1
Descriptor
Interface #0
Descriptor
Interface #0
Descriptor
Configuration #1
Descriptor
Configuration #2
Descriptor
Configuration #3
Descriptor
Device
Descriptor
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...