www.ti.com

Interface #0

Interface #1

PCM2901

PCM2903

SLES034C – MARCH 2002 – REVISED NOVEMBER 2007

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

Alternative setting #0 describes the standard audio control interface. A terminal constructs the audio control

interface. The PCM2901/2903 has the following five terminals.

• Input terminal (IT #1) for isochronous-out stream

• Output terminal (OT #2) for audio analog output

• Feature unit (FU #3) for DAC digital attenuator

• Input terminal (IT #4) for audio analog input

• Output terminal (OT #5) for isochronous-in stream

Input terminal #1 is defined as USB stream (terminal type 0x0101). Input terminal #1 can accept 2-channel audio

streams constructed by left and right channels. Output terminal #2 is defined as a speaker (terminal type

0x0301). Input terminal #4 is defined as microphone (terminal type 0x0201). Output terminal #5 is defined as a

USB stream (terminal type 0x0101). Output terminal #5 can generate 2-channel audio streams constructed by

left and right channels. Feature unit #3 supports the following sound control features.

• Volume control

• Mute control

The built-in digital volume controller can be manipulated by an audio class specific request from 0 dB to –64 dB

in 1-dB steps. Changes are made by incrementing or decrementing by one step (1 dB) for every 1/fS time interval

until the volume level has reached the requested value. Each channel can be set for different values. The master

volume control is not supported. A request to the master volume is stalled and ignored. The built-in digital mute

controller can be manipulated by audio class-specific request. A master mute control request is acceptable. A

request to an individual channel is stalled and ignored.

Interface #1 is defined as the audio streaming data-out interface. Interface #1 has the following seven alternative

settings. Alternative setting #0 is the zero-bandwidth setting.

ALTERNATIVE

TRANSFER

SAMPLING RATE

DATA FORMAT

SETTING

MODE

(kHz)

00

Zero bandwidth

01

16 bit

Stereo

2s complement (PCM)

Adaptive

32, 44.1, 48

02

16 bit

Mono

2s complement (PCM)

Adaptive

32, 44.1, 48

03

8 bit

Stereo

2s complement (PCM)

Adaptive

32, 44.1, 48

04

8 bit

Mono

2s complement (PCM)

Adaptive

32, 44.1, 48

05

8 bit

Stereo

Offset binary (PCM8)

Adaptive

32, 44.1, 48

06

8 bit

Mono

Offset binary (PCM8)

Adaptive

32, 44.1, 48

22

Submit Documentation Feedback

Copyright © 2002–2007, Texas Instruments Incorporated

Product Folder Link(s): PCM2901 PCM2903