Texas Instruments PCM2706 Evaluation Module PCM2706EVM-U PCM2706EVM-U Datenbogen
Produktcode
PCM2706EVM-U
Analog Out
IT
TID1
OT
TID2
FU
UID3
Standard Audio Control Interface (I/F #0)
Endpoint #0
Endpoint #2
(I/F #1)
Endpoint #5
(I/F #2)
Default
Endpoint
Audio Streaming
Interface
HID Interface
PCM2704C/5C/6C/7C
SBFS036A – AUGUST 2011 – REVISED JULY 2012
Device Configuration
illustrates the USB audio function topology. The PCM2704C/5C/6C/7C have three interfaces. Each
interface is enabled by different alternative settings.
Figure 23. USB Audio Function Topology
Interface #0 (Default/Control Interface)
Interface #0 is the control interface. Setting #0 is the only possible setting for interface #0. Setting #0 describes
the
the
standard
audio
control
interface.
The
audio
control
interface
consists
of
a
terminal.
The
PCM2704C/5C/6C/7C have three 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 #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). Feature unit #3 supports these sound control features:
•
audio streams consisting of left and right channels. Output terminal #2 is defined as a speaker (terminal type
0x0301). Feature unit #3 supports these 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 steps of 1 dB. Changes are made by incrementing or decrementing one step (that is, 1 dB) for every 1/f
in steps of 1 dB. Changes are made by incrementing or decrementing one step (that is, 1 dB) for every 1/f
S
time
interval, until the volume level reaches the requested value. Each channel can be set to a separate value. 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 an audio-class-specific request. A master mute control request is
acceptable. A mute control request to an individual channel is stalled and ignored. The digital volume control
does not affect either the S/PDIF or I
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 an audio-class-specific request. A master mute control request is
acceptable. A mute control request to an individual channel is stalled and ignored. The digital volume control
does not affect either the S/PDIF or I
2
S outputs (PCM2706C/7C only).
18
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s):