PCM2912A Datasheet, PDF (23/32 Pages) Texas Instruments – AUDIO CODEC WITH USB INTERFACE, MONO MICROPHONE INPUT AND STEREO HEADPHONE OUTPUT

PCM2912A
www.ti.com.......................................................................................................................................................................................... SLES230 – SEPTEMBER 2008
INTERFACE SEQUENCE
Power-On, Attach, and Play Back Sequence
The PCM2912A is ready for setup when the reset sequence has finished and the USB bus is attached. After a
connection has been established, the PCM2912A is ready to accept USB audio data. While waiting for the audio
data (that is, in an idle state), the analog output is set to bipolar zero (BPZ).
When receiving the audio data, the PCM2912A stores the first audio packet, which contains 1-ms audio data,
into the internal storage buffer. The PCM2912A starts playing the audio data when the subsequent Start of
Frame (SOF) packet is detected, as shown in Figure 33.
V_BUS (pin 2)
0V
2.5 V (typ)
5.0 V (typ)
D+ (pin 4), ^{Bus Idle}
D- (pin 3)
Bus Reset
Set Configuration
1st Audio Data
2nd Audio Data
SOF
SOF
SOF
SSPND (pin 29)
V_OUTL (pin 18),
V_OUTR (pin 22)
700 ms
Internal Reset
Device Setup
1 ms
Ready for Setup
Ready for Playback
Figure 33. Initial Sequence
Copyright © 2008, Texas Instruments Incorporated
Product Folder Link(s): PCM2912A
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