WM9703

Production Data

WOLFSON MICROELECTRONICS LTD

PD Rev 3.4 January 2001

14

GAIN CONTROL REGISTER LOCATION VERSUS ID

PGA

CODEC ID

CONTROL REG

MUTE DEFAULT

DAC

0x

10

11

18h

Muted (bit-15)

AND with 38h, 7, 15

AND with 36h, 7, 15

Mixer

0x

10

11

72h

Not-muted (bit-15)

Volume

0x

10

11

02h

38h

36h

Muted (15)

Muted (7 and 15)

Muted (7 and15)

Table 5 Gain Control Register Location Versus ID

MASTER/SLAVE ID0/1 SUPPORT

WM9703 supports operation as either a master or a slave codec. Configuration of the device as

either a master or as a slave, is selected by tying the CID pins CID0 and CID1, pins 45 and 46 on the

package.

Fundamentally, a device identified as a master (ID = 00) produces BITCLK as an output, whereas a

slave (any other ID) must be provided with BITCLK as an input. This has the obvious implication that

if the master device on an AC link is disabled, the slave devices cannot function.

The AC’97 Revision 2.1 specification defines that the CID pins have inverting sense, and are

provided with internal weak pull ups. Therefore, if no connections are made to the CID0/1 pins, then

the pins pull hi and an ID = 00 is selected, i.e. master. External connects to ground will select other

IDs.

PIN46 CID1

PIN45 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

WM9703 supports the AMAP function whereby selection of an ID will automatically map the data

from the interface onto the PCM DACs. This allows a 6-channel audio system to be built using 3

WM9703 devices, with one device configured as a master (ID 00) and the other two as slaves (ID 10

and 11). (See figure 10). In this case, the main channel DACs will have mapped onto them the data

from the normal, surround, and LFE and centre slots respectively, without any user selection.

CODEC ID

AC–LINK FRAME DATA

USED FOR DACS

COMMENTS

PCM left DAC uses

data from slot No.

PCM right DAC uses

data from slot No.

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 register 28h, bits D15 and D14

Table 7 Default Slot to DAC Mappings Based on Codec ID

CODEC ID

SLOTS MAPPED

TO DACS

00 or 01

3 and 4

10

7 and 8

11

6 and 9

Table 8 Slot to DAC and Mapping Based on Codec ID