XE3005 查看數據表（PDF） - Semtech Corporation

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XE3005

Low-Power Audio CODEC

Semtech Corporation 

XE3005/XE3006

3 SERIAL COMMUNICATIONS

3.1 SERIAL AUDIO INTERFACE

The Serial Audio Interface is a 4-wire interface for bi-directional communication of audio data. The 4 terminals are listed

below:

• BCLK:

• FSYNC:

• SDI:

• SDO:

Bit serial clock, one clock cycle corresponds to one data bit transmitted or received.

Frame Synchronization. This signal indicates the start of a data word. The frequency of the FSYNC

corresponds to the sample frequency of the CODEC.

Serial Data In, data received from external device and sent to DAC.

Serial Data Out, data received from ADC and sent to external device.

The same clock (BCLK) and synchronization (FSYNC) signals are used for both sending and receiving. The

synchronization signal FSYNC must have a fixed ratio with the master clock signal MCLK.

The Serial Audio Interface supports two formats that are commonly used for audio/voice CODECs and that are referred to

as SFS (Short Frame Synchronization) and LFS (Long Frame Synchronization). Data can be transmitted and received in

2 channels. Which channel is selected depends on the programmed values in the registers. The two interface protocols

are shown below.

FSYNC

BCLK

SDI

SDO

channel 1, sample n

channel 2, no data

channel 1, sample n+1

n15 n14

n0 -

-

- n+115

n15 n14

msb

n0 -

-

lsb

- n+115

msb

Figure 13: Audio interface timing LFS mode, channel 1

FSYNC

BCLK

SDI

SDO

channel 1, sample n

channel 2, sample n

channel 1, sample n+1

n15 n14

n0 - -

- n+115

n15 n14

msb

n0 - -

lsb

- n+115

msb

Figure 14: Audio interface timing in SFS mode, channel 1

© Semtech 2005

www.semtech.com

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