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Device Configuration

Standard AudioControlinterface(IF#0)

Endpoint#0

Endpoint#1

(IF#1)

IT

TID3

FU

UID5

Analog out

Analog in

Default endpoint

Audiostreaminginterface

Endpoint#2

(IF#2)

Audio streaminginterface

F U

UID2

F U

UID8

S

UID4

OT

TIDB

OT

TID6

IT

TID1

IT

TID7

UIDA

S

Interface #0

PCM2912

SLES216 – FEBRUARY 2008

Figure 31 illustrates USB audio function topology. The PCM2912 has three interfaces. Each interface is

constructed by some alternative settings.

Figure 31. USB Audio Function Topology

Interface #0 is for control interface. Alternative setting #0 is the only possible setting for interface #0. Alternative

setting #0 describes the standard audio control interface. Audio control interface is constructed by a terminal.

The PCM2912 has ten terminals as follows.

• Input Terminal (Terminal ID#1) for audio analog input for sidetone

• Feature Unit (Unit ID#2) for sidetone PGA

• Input Terminal (Terminal ID#3) for isochronous-out stream

• Mixer Unit (Unit ID#4) for sidetone mixing

• Feature Unit (Unit ID#5) for analog output PGA

• Output Terminal (Terminal ID#6) for audio analog output

• Input Terminal (Terminal ID#7) for audio analog input

• Feature Unit (Unit ID#8) for analog input PGA

• Mixer Unit (Unit ID#A) for analog input

• Output Terminal (Terminal ID#B) for isochronous-in stream

Copyright © 2008, Texas Instruments Incorporated

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Product Folder Link(s): PCM2912