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Interface #2

Interface #3

End-Points

PCM2901

PCM2903

SLES034C – MARCH 2002 – REVISED NOVEMBER 2007

Interface #2 is defined as the audio streaming data-in interface. Interface #2 has the following 19 alternative

settings. Alternative setting #0 is the zero-bandwidth setting. All other alternative settings are operational

settings.

ALTERNATIVE

SAMPLING RATE

DATA FORMAT

TRANSFER MODE

SETTING

(kHz)

00

Zero bandwidth

01

16 bit

Stereo

2s complement (PCM)

Asynchronous

48

02

16 bit

Mono

2s complement (PCM)

Asynchronous

48

03

16 bit

Stereo

2s complement (PCM)

Asynchronous

44.1

04

16 bit

Mono

2s complement (PCM)

Asynchronous

44.1

05

16 bit

Stereo

2s complement (PCM)

Asynchronous

32

06

16 bit

Mono

2s complement (PCM)

Asynchronous

32

07

16 bit

Stereo

2s complement (PCM)

Asynchronous

22.05

08

16 bit

Mono

2s complement (PCM)

Asynchronous

22.05

09

16 bit

Stereo

2s complement (PCM)

Asynchronous

16

0A

16 bit

Mono

2s complement (PCM)

Asynchronous

16

0B

8 bit

Stereo

2s complement (PCM)

Asynchronous

16

0C

8 bit

Mono

2s complement (PCM)

Asynchronous

16

0D

8 bit

Stereo

2s complement (PCM)

Asynchronous

8

0E

8 bit

Mono

2s complement (PCM)

Asynchronous

8

0F

16 bit

Stereo

2s complement (PCM)

Synchronous

11.025

10

16 bit

Mono

2s complement (PCM)

Synchronous

11.025

11

8 bit

Stereo

2s complement (PCM)

Synchronous

11.025

12

8 bit

Mono

2s complement (PCM)

Synchronous

11.025

Interface #3 is defined as the interrupt data-in interface. Alternative setting #0 is the only possible setting for

interface #3. Interface #3 constructs the HID consumer control device. Interface #3 reports the following three

key statuses.

• Mute (0xE209)

• Volume up (0xE909)

• Volume down (0xEA09)

The PCM2901/2903 has the following four end-points.

• Control end-point (EP #0)

• Isochronous-out audio data stream end-point (EP #2)

• Isochronous-in audio data stream end-point (EP #4)

• HID end-point (EP #5)

The control end-point is a default end-point. The control end-point is used to control all functions of the

PCM2901/2903 by the standard USB request and USB audio-class-specific request from the host. The

isochronous-out audio data stream end-point is an audio sink end-point, which receives the PCM audio data. The

isochronous-out audio data stream end-point accepts the adaptive transfer mode. The isochronous-in audio data

stream end-point is an audio source end-point, which transmits the PCM audio data. The isochronous-in audio

data stream end-point uses asynchronous transfer mode. The HID end-point is an interrupt-in end-point. HID

end-point reports HID0, HID1, and HID2 pin status every 32 ms.

The human interface device (HID) pins are defined as consumer control devices. The HID function is designed

as an independent end-point from both isochronous-in and -out end-points. This means that the device affected

by the HID operation depends on the host software. Typically, the HID function affects the primary audio-out

device.

Copyright © 2002–2007, Texas Instruments Incorporated

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Product Folder Link(s): PCM2901 PCM2903