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INTERFACE SEQUENCE

Power-On, Attach, and Play Back Sequence

D+(pin 4),

D–(pin 3)

2.5 V (typ.)

0 V

700 µs

Internalreset

Readyforsetup

Devicesetup

1staudiodata

SOF

2ndaudiodata

1 ms

Readyforplayback

SSPND(pin 29)

Busreset

Setconfiguration

SOF

SOF

BusIdle

5.0 V

(typ.)

BPZ

V

(pin2)

BUS

PCM2912

SLES216 – FEBRUARY 2008

The PCM2912 is ready for setup when the reset sequence has finished and the USB bus is attached. After a

connection has been established by setup, the PCM2912 is ready to accept USB audio data. While awaiting the

audio data (idle state), the analog output is set to bipolar zero (BPZ).

When receiving the audio data, the PCM2912 stores the first audio packet, which contained 1-ms audio data, into

the internal storage buffer. The PCM2912 starts playing the audio data when detecting the following Start of

Frame (SOF) packet.

Figure 33. Initial Sequence

Copyright © 2008, Texas Instruments Incorporated

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Product Folder Link(s): PCM2912