Datasheet

PCM2906C

www.ti.com

SBFS037 –NOVEMBER 2011

Interface #0

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

setting #0 describes the standard audio control interface. The audio control interface consists of a single

terminal. The PCM2906C 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 a USB stream (terminal type 0x0101). Input terminal #1 can accept two-channel

audio streams consisting of left and right channels. Output terminal #2 is defined as a speaker (terminal type

0x0301). Input terminal #4 is defined as a line connector (terminal type 0x0603). Output terminal #5 is defined as

a USB stream (terminal type 0x0101). Output terminal #5 can generate two-channel audio streams composed of

left and right channel data. 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/f

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

Interface #1 is the audio streaming data-out interface. Interface #1 has the five alternative settings listed in

Table 5. Alternative setting #0 is the zero-bandwidth setting. All other alternative settings are operational settings.

Table 5. Interface #1 Alternative Settings

ALTERNATIVE TRANSFER SAMPLING RATE

SETTING DATA FORMAT MODE (kHz)

00 Zero bandwidth

01 16-bit Stereo Twos complement (PCM) Adaptive 32, 44.1, 48

02 16-bit Mono Twos complement (PCM) Adaptive 32, 44.1, 48

03 8-bit Stereo Twos complement (PCM) Adaptive 32, 44.1, 48

04 8-bit Mono Twos complement (PCM) Adaptive 32, 44.1, 48

Product Folder Link(s): PCM2906C