AV2636

Product Datasheet

DIGITAL AUDIO DATA INTERFACE

The serial audio data is send to the device through a three-wire interface. The interface consists of three

input pins that are serial clock (SC), serial data (SD) and sync-frame (SF). The sync-frame is also a

left/right channel indicator. Three interface formats are supported.

•

I

•

Right justified mode

•

DSP mode

All formats send MSB first. The audio data is in 2’s complement format. The mode selection can be either

in auto-detect mode or programmable mode.

The three-wire digital audio data interface timing specification is shown at the following diagram.

SF

SC

SD

The timing characteristics are shown at the following table.

Symbol

Description

Min

Max

Units

SC clock cycle time

50

ns

SC pulse width high

20

ns

SC pulse width low

20

ns

SD data setup time relative to SC rising edge

10

ns

SD data hold time relative to SC rising edge

10

ns

SF hold time relative to SC rising edge

10

ns

SF setup time relative to SC rising edge

10

ns

I

In I

data is time multiplexed with the frame signal SF indicating left and right channel data. SF is low

during left channel data and high during right channel data. The SF is also a timing signal for the

start of each word of left and right channel.

The MSB of the audio data SD is sampled on the second rising edge of SC following SF transition.

Word lengths of 16/18/20/24 bits are supported.

AVS Technology, Inc.

6-16

August 18, 2004

www.avstech.com