uda1335h NXP Semiconductors, uda1335h Datasheet - Page 15

• Manufacturer Part Number: uda1335h
• Description: Universal Serial Bus Usb Audio Playback Recording Peripheral Aprp
• Manufacturer: NXP Semiconductors

Philips Semiconductors
H
The inputs defined on the UDA1335H are transmitted via
the USB to the host according to the HID class. The host
responds with the appropriate settings via the audio device
class for the audio related parts or via the HID class for the
HID related inputs and outputs of the UDA1335H.
A HID descriptor is necessary to inform the host about the
conception of the user interface. The host communicates
via the HID device driver using either the control pipe or
the interrupt pipe. The UDA1335H is using USB
endpoint 0 (control pipe) to respond to the HID specific
‘Get/Set Report request’ to receive or transmit data from or
to the UDA1335H. The UDA1335H uses the status
interrupt endpoint as interrupt pipe for polling
asynchronous data.
The UDA1335H is a high-speed device. The maximum
transaction size is 64 bytes per USB frame and the polling
rate is defined at a maximum of every 1 ms.
The host requests the configuration descriptor which
includes the standard interface descriptor, the HID
endpoint descriptor and the HID descriptor. The HID
device driver of the host then requests the report
descriptor.
Report descriptors are composed of pieces of information
about the device. Each piece of information is called an
item. All items have a 1-byte prefix that contains the item
tag, type and size. In the UDA1335H only the short item
basic type is used.
The hosts HID device driver will parse the report descriptor
and the defined items. By examining all of these items, the
HID class driver is able to determine the size and
composition of data reports from the device.
The main items of the UDA1335H are input reports. Input
reports are sent via the interrupt pipe (UDA1335H USB
endpoint 3). Input reports can be requested by the host via
the control endpoint (USB endpoint 0).
The UDA1335H supports a maximum of two push-buttons
(six with I
feature of the UDA1335H.
If pressed by the user the pushbutton will go to its ‘ON’
state, if not pressed the push-button will go back to its
‘OFF’ state.
For more information about the input functions of the
UDA1335H see the application documentation of the
device.
1998 Aug 28
UMAN INTERFACE DEVICE SPECIFIC DESCRIPTORS
Universal Serial Bus (USB) Audio
Playback Recording Peripheral (APRP)
2
C-bus expanders), which represent a certain
15
Controlling the USB APRP
The sound features as defined in the “USB Device Class
Definition for Audio Devices” are mapped on the
UDA1335H specific feature registers by the
microcontroller. These specific sound features are:
These specific features can be activated via the host
(audio device class requests) or via the GP I/O pins (HID
plus audio device class requests). The user is able to
download the necessary configuration data for different
applications (definition of the function of the GP pins, with
or without digital I/O functionality etc.) via the configuration
map. The mapping and control of the standard USB audio
features and UDA1335H specific features is described
below.
Volume control
Volume control is possible via the host or via predefined
GP I/O pins. The setting of 0 dB is always referenced to
the maximum available volume setting. Table 7 gives the
mapping of wVolume value (as defined in the “USB
Device Class Definition for Audio Devices” ) upon the
actual volume setting of the USB APRP. When using the
UDA1335H, the range is 0 dB down to 60 dB (in steps of
1 dB) and
volume is possible.
It should be noted that wVolume
used. Values above 0 dB are returned as 0 dB.
The volume value at start-up of the device is defined in the
selected configuration map.
Balance control is possible via the separate volume control
option of both channels. Therefore the characteristics of
the balance control are equal to the volume control
characteristics.
Volume control (separate for left and right stereo
channels, no master channel)
Mute control (only master channel)
Treble control (only master channel)
Bass control (only master channel)
Dynamic bass boost control (only master channel).
dB. Independant control of ‘left’/’right’
LSB
Preliminary specification
B7 to B0 are not
UDA1335H