DS4201

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102099

EXTENTION UNIT

The extension Unit (XU) is used to add vendor specific features to a USB audio function. The XU in the

DS4201, XU:UID9, is used to select between two available output ranges for the sigma–delta DAC:

must be selected. For 5V operation, either range can be used. The command and control parameter used

for the XU SET/GET request is defined in APPENDIX A.

EXTENTION UNIT DEFAULT SETTING

The power–on default setting of the XU is:

OUTPUT_DOUBLE_SELECTOR = FALSE

Feature Units

As defined by the ADC specification, the Feature Unit (FU) provides basic property control of an audio

signal. The FU descriptor reports what controls exist for each channel that passes through the FU as well

as a master control. All FUs have a single input and output pin for the audio cluster being controlled. The

audio cluster can contain multiple logical channels (left, right, etc.) which are individually or group

controlled by FU commands. As shown in Figure 3, FU:UID5 operates on the cluster from XU:UID9,

FU:UID6 operates on the cluster from IT:TID2 and FU:UID7 operates on the cluster from IT:TID3. Table

1 lists the cluster channels and properties supported by each FU. As shown in the table, MUTE is the only

control property supported by the DS4201 FUs. FU commands are documented in APPENDIX A.

FEATURE UNIT PROPERTIES Table 1

FEATURE UNIT

LOGICAL CHANNEL

SIGNAL

SUPPORTED PROPERTIES

FU:UID5 Channel 0

Master

MUTE

FU:UID5 Channel 1

Left DAC

MUTE

FU:UID5 Channel 2

Right DAC

MUTE

FU:UID6 Channel 0

Master

MUTE

FU:UID6 Channel 1

Left AUX

MUTE

FU:UID6 Channel 2

Right AUX

MUTE

FU:UID7 Channel 0

Master

MUTE

FU:UID7 Channel 1

Left MIC

MUTE

FU:UID7 Channel 2

Right MIC

MUTE

FEATURE UNITS DEFAULT SETTINGS

The power–on default settings of the three FU’s are:

FU:UID5 – Channels 0–2, MUTE = false

FU:UID6 – Channels 0–2, MUTE = false

FU:UID7 – Channels 0–2, MUTE = false