CM103+ C-Media Electronics, Inc., CM103+ Datasheet - Page 16

• Manufacturer Part Number: CM103+
• Description: 16-Bit Stereo USB Audio Controller
• Manufacturer: C-Media Electronics, Inc.

Date: 09/25/2005
HID feature is provided by CM103+ so user setting to Volume-Up, Volume-Down,
Playback-Mute button pin, and the Digital-Rotary-Encoder for Volume Control is
reported to the host to synchronize host side setting.
USB protocols can configure devices at startup or when they are plugged in at run time.
These devices are broken into various device classes. Each device class defines the
common behavior and protocols for devices that serve similar functions. The HID
(Human Interface Device) class is one of the device classes.
The HID class consists primarily of devices that are used by humans to control the
operation of computer systems. Typical examples of HID class devices include:
Offset
6.3 HID FEATURE
0
1
2
3
HID Interface Descriptor
6.3.1 WHAT’S HID
6.3.2 HID DESCRIPTOR
-
-
-
-
bInterfaceNumber
bAlternateSetting
bDescriptorType
Keyboards and pointing devices, for example: mouse, trackballs, and
joysticks.
Front-panel controls, for example: knobs, switches, buttons, and sliders.
Controls that might be found on devices such as VCR remote controls,
games or simulation devices, for example: data gloves, throttles, and steering
wheels.
Devices that may not require human interaction but provide data in a similar
format to HID class devices, for example: bar-code readers, thermometers,
or voltmeters.
bLength
Field
Size
USB Stereo Audio Chip for Digital Speakers Application
1
1
1
1
Value (Hex)
04
02
00
- 16 -
09
Size of this descriptor: 9 byte
INTERFACE descriptor type
Number of Interface
alternate 0
Description
Version: 1.01
CM103+