STAC9766 datasheet(73/97 Pages) IDT

73 / 97 page

STAC9766/9767

TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING

PC AUDIO

IDT™

STAC9766/9767

V 7.4 12/06

TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING

9-5

DL4:DL0

Buffer delays: CODEC will provide a delay measurement for the input and output

channels. Software will use this value to accurately calculate audio stream

position with respect to what is been reproduced or recorded. These values are

in 20.83 microsecond (1/48000 second) units.

For output channels, this timing is from the end of AC Link frame in which the

sample is provided, until the time the analog signal appears at the output pin. For

input streams, this is from when the analog signal is presented at the pin until the

representative sample is provided on the AC Link.

Analog in and out paths are not considered as part of this delay.

The measurement is a 'typical' measurement, at a 48 KHz sample rate, with

minimal in-CODEC processing (i.e., 3D effects are turned off.)

00h - Information not provided

01h…1Eh - Buffer delay in 20.83

µs units

1Fh - reserved

These bits are read/write and are not reset on RESET#.

The default value is the delay internal to the CODEC. The BIOS may add to this

value the known delays external to the CODEC, such as for an external

amplifier.

Information Valid Bit: Indicates whether a sensing method is provided by the

CODEC and if information field is valid. This field is updated by the CODEC.

0h--After CODEC RESET# de-assertion, it indicates the CODEC does NOT

provides sensing logic and this bit will be Read Only. After a sense cycle is

completed indicates that no information is provided on the sensing method.

1h--After CODEC RESET# de-assertion, it indicates the CODEC provides

sensing logic for this I/O and this bit is Read/Write. After clearing this bit by

writing 1, when a sense cycle is completed the assertion of this bit indicates

that there is valid information in the remaining descriptor bits. Writing “0” to

this bit has no effect.

BIOS should NOT write this bit, as it is reset on RESET#.

3-1

RESERVED Bit not used, should read back 0

FIP

Function Information Present

This bit is set to a 1 indicates that the G[4:0], INV, DL[4:0](Register 68h, Page

01h) and ST[2:0](register 6Ah, Page 01h) are supported and R/W capable.

This bit is Read Only.

Table 24. Reg 68h Default Values

Reg 66h Function Code

Reg 68h Default Value

00h Line Out

0010h

01h Headphone Out

0010h

05h Mic1

0010h

06h Mic2

0010h

All other Function Codes

0000h

For RESET#: Reg 68h default value is 0000h.

Bit(s) Reset Value

Name

Description

STAC9766 Datasheet(PDF) 73 Page - Integrated Device Technology

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