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Technical Support
On-Line Manuals
RL-ARM User's Guide (MDK v4)
RL-RTX
RL-FlashFS
RL-TCPnet
RL-CAN
RL-USB
RL-USB for USB Device Applications
RL-USB Device Library
RL-USB Device Features
RL-USB Device Software Stack
RL-USB Device Functions
RL-USB Device Source Files
RL-USB Device Configuration
Audio Device (ADC) Options
Communication Device (CDC) - ACM Options
Human Interface Device (HID) Options
Mass Storage Device (MSC) Options
Create USB Device Applications
Create ADC Applications
Create CDC ACM Applications
Create HID Applications
Create MSC Applications
Create Composite Applications
Test USB Device Applications
Compliance Tests
Test HID Client Application
RL-USB for USB Host Applications
RL-USB Host Library
RL-USB Host Features
RL-USB Host Software Stack
RL-USB Host Functions
RL-USB Host Source Files
RL-USB Host Configuration
Host Controller Driver Selection
Host Controller Driver Configuration
Host Class Driver Selection
Create USB Host Applications
Create USB Host HID Applications
HID_Kbd Example
Create USB Host MSC Applications
Create USB Host Class Driver
RL-USB Host Constants and Structures
Error constants
Speed constants
Transaction Packet Type constants
Transaction Error Type constants
USB Request Block structure (USBH_URB)
Endpoint structure (USBH_EP)
Driver Capabilites structure (USBH_HCI_CAP)
Device Class Instance structure (USBH_DCI)
Host Controller Instance structure (USBH_HCI)
Host Controller Driver structure (USBH_HCD)
USB Concepts
USB Transfer Rates
USB Network
Basic Communication Model
USB Protocol
Control Transfer
Interrupt Transfer
Isochronous Transfer
Bulk Transfer
Descriptors
Device Configuration
Device Descriptor
Configuration Descriptor
Interface Descriptor
Endpoint Descriptor
Device Qualifier Descriptor
Example Programs
Library Reference
Appendix
Device Configuration
When a USB device is attached to or removed from the USB, the host uses a process known as bus enumeration to identify and manage the device.
The data requested by the host are stored in a hierarchy of descriptors. Descriptors are arrays of data, which fully describe the device.
The minimum and required number of descriptors are:
- One Device Descriptor.
- One Configuration Descriptor.
- One Interface Descriptor.
- Three Endpoint Descriptors (one control, one IN, and one OUT).
Complex devices have multiple interfaces. Each interface can have a number of endpoints representing a functional unit. For example, a voice-over-IP phone might have:
- One audio class interface with 2 endpoints for transferring audio data in each direction.
- One HID interface with a single IN interrupt endpoint for a built-in keypad.
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