ALC655 Datasheet

Six-Channel AC’97 2.3 Audio Codec

19

Rev 1.3

Bit

Type

Function

0: off

1: on

4

R/W

Analog Input Pass to Surround Control

0: off

1: on

3:1

-

Reserved

0

R/W

Surround Output Source.

0: S-OUT is the real surround output. (default)

1: S-OUT is the duplicated output of LINE-OUT

6.3 Discovery Descriptor (Page ID-01h)

These registers are defined in AC’97 2.3 for sensing and analog plug&play functions.

6.3.1 MX62 PCI Sub System ID

Default: FFFFh

Bit

Type

Function

15:0

R/W

PCI Sub System Vendor ID

This register can be written once only after power on, and is not affected by AC97 cold reset. System

manufacture’s BIOS can set its own sub-system ID.

The default value FFFFh means this register is implemented and data is not set by BIOS.

6.3.2 MX64 PCI Sub Vendor ID

Default: FFFFh

Bit

Type

Function

15:0

R/W

PCI Vendor ID

This register can be written once only after power on, and is not affected by AC97 cold reset. System

manufacture’s BIOS can set its own sub-vendor ID.

The default value FFFFh means this register is implemented and data is not set by the BIOS.

6.3.3 MX66 Sense Function Select

Default: 0000h

Bit

Type

Function

15:5

Reserved

4:1

R/W

Function Code bits, FC[3:0]

These bits specify the type of audio function described in page ID-01h MX66, MX68, and MX6A.

0h: FRONT OUT

1h: SURROUND OUT

5h: MIC1 In

6h: MIC2 In

7h: LINE In

Others: Not supported

0

R/W

Tip or Ring Selection, T/R

This bit sets which jack conductor the sense value is measured from. It is combined with FC[3:0].

0: Tip (Left channel)

1: Ring (Right channel)