uda1321 NXP Semiconductors, uda1321 Datasheet - Page 12

• Manufacturer Part Number: uda1321
• Description: Universal Serial Bus Usb Digital-to-analog Converter Dac
• Manufacturer: NXP Semiconductors

Philips Semiconductors
The programmable part can be retrieved from one of four
configuration maps located in the firmware or from an
I
maps can be selected depending on the logical
combination of GP3 and GP0. It is possible to overwrite
this configuration map with a configuration map loaded
from an I
A
The audio device class is partly specified with standard
descriptors and partly with specific audio device class
descriptors. The standard descriptors specify the number
and the type of the interface or endpoint. The UDA1321
supports 7 different audio modes:
Each mode is defined as an alternate setting of the audio
interface, selectable with the standard audio streaming
interface descriptor bAlternateSetting field.
The seven alternate settings are described in more detail
by the specific audio device class descriptors.
The UDA1321 supports the Input Terminal (IT), Output
Terminal (OT) and the Feature Unit (FU) descriptors.
The input and output terminals are not controllable via the
USB. The feature unit provides the basic manipulation of
the incoming logical channels.
The supported sound features are:
1998 Oct 06
2
handbook, full pagewidth
C-bus EEPROM. At start-up one of four configuration
UDIO DEVICE CLASS SPECIFIC DESCRIPTORS
8-bit Pulse Code Modulation (PCM) mono or stereo
audio data
16-bit PCM mono or stereo audio data
24-bit PCM mono or stereo audio data
Zero bandwidth mode.
Volume control
Mute control
Treble control
Bass control
Bass boost control.
Universal Serial Bus (USB)
Digital-to-Analog Converter (DAC)
2
C-bus EEPROM.
INPUT TERMINAL
IT
Fig.5 Audio function topology.
FEATURE UNIT
FU
12
Table 2 Audio bandwidth at each audio mode
The maximum number of audio data samples within a USB
packet arriving on the isochronous sink endpoint is
restricted by the buffer capacity of this isochronous
endpoint. The maximum buffer capacity is 336 bytes/ms.
For each alternate setting with audio, a maximum
bandwidth is claimed as indicated in the standard
isochronous audio data endpoint descriptor
wMaxPacketSize field. To allow a small overshoot in the
number of audio samples per packet, the top sample
frequency of 55 kHz is taken in the calculation of the
bandwidth for each alternate setting. For each alternate
setting, with its own isochronous audio data endpoint
descriptor, wMaxPacketSize field is then defined as
described in Table 2.
Although in a specific UDA1321 application no endpoint
control properties can be used upon the isochronous
adaptive sink endpoint, the descriptors are still necessary
to inform the host about the definition of this endpoint:
isochronous, adaptive, sink, continuous sampling
frequency (at input side of this endpoint) with lower bound
of 5 kHz and upper bound of 55 kHz.
The audio class specific descriptors can be requested with
the ‘Get descriptor: configuration request’, which returns
all the descriptors, except the device descriptor.
H
The inputs defined on the UDA1321 are transmitted via the
USB to the host according to the HID class. The host
8-bit PCM; mono
8-bit PCM; stereo
16-bit PCM; mono
16-bit PCM; stereo
24-bit PCM; mono
24-bit PCM; stereo
UMAN INTERFACE DEVICE SPECIFIC DESCRIPTORS
AUDIO MODE
MBK530
OUTPUT TERMINAL
OT
56 (
112 (
112 (
224 (
168 (
336 (
Preliminary specification
8
wMaxPacketSize
8
16
16
24
24
8
8
8
8
8
8
1
2
UDA1321
1
2
1
2
56)
56)
56)
56)
56)
56)