WM9704Q

Production Data

WOLFSON MICROELECTRONICS LTD

PD Rev 2.3 January 2001

16

PIN 46 CID1

PIN 45 CID0

ID SELECTED

MASTER

OR SLAVE

BITCLK

NC

NC

00

Master

Output

NC

Ground

01

Slave

Input

Ground

NC

10

Slave

Input

Ground

Ground

11

Slave

Input

Table 6 ID Selection

WM9704Q supports the AMAP function whereby selection of an ID will automatically map the data

from the interface onto the PCM DACs.

AC–LINK FRAME DATA USED FOR DACS

CODEC ID

PCM left DAC uses

data from slot no.

PCM right DAC uses

data from slot no.

COMMENTS

00

3

4

Original definition (master)

01

3

4

Original definition (docking)

10

7

8

Left/right surround channels

11

6

9

Centre/LFE channels

The Codec ID is available to the controller via registers 28h and C3, bits D15 and D14

Table 7 Default Slot to DAC Mappings Based on Codec ID

The above automatic mapping of data to slots is extended when the device is operated in the

alternative modes selectable via the mode pins. In these cases the selection of which data slots are

mapped onto internal DACs or I

MODE

CODEC

ID

SLOTS MAPPED

TO FRONT DACS

SLOTS MAPPED

TO REAR DACS

DATA TO

I

44

DATA TO

I

48

00 or 01

3 and 4

10

7 and 8

Rev 2.1

(00)

11

6 and 9

Not supported

in this mode

Not supported

in this mode

Not supported

in this mode

00 or 01

3 and 4

7 and 8

6 and 9

10

7 and 8

3 and 4

6 and 9

Rev 2.1

6-channel

(01)

11

6 and 9

Not supported

in this mode

7 and 8

3 and 4

00 or 01

3 and 4

7 and 8

7 and 8

6 and 9

10

7 and 8

3 and 4

3 and 4

6 and 9

Quad (10)

11

6 and 9

7 and 8

7 and 8

3 and 4

Table 8 Slot to DAC and I2S Mapping Based on Mode and Codec ID

SLAVE CODEC REGISTER ACCESS DEFINITIONS

Master Codec access is exactly as defined for AC’97. For slave Codec access, the AC’97 Digital

Controller must invalidate the tag bits for Slot 1 and 2 Command Address and Data (Slot 0, bits 14

and 13) and place a non-zero value (01, 10, or 11) into the Codec ID field (Slot 0, bits 1 and 0).

Slave Codecs disregard the Command Address and Command Data (Slot 0, bits 14 and 13) tag bits

when they see a 2-bit Codec ID value (Slot 0, bits 1 and 0) that matches their configuration. In a

sense the Slave Codec ID field functions as an alternative Valid Command Address (for Slave reads

and writes) and Command Data (for Slave writes) tag indicator.

Slave Codecs must monitor the Frame Valid bit, and ignore the frame (regardless of the state of the

Slave Codec ID bits) if it is not valid. AC’97 Digital Controllers should set the frame valid bit for a

frame with a slave register access, even if no other bits in the output tag slot except the Slave Codec

ID bits are set.