WM9704CFT/V Wolfson Microelectronics plc, WM9704CFT/V Datasheet - Page 15

• Manufacturer Part Number: WM9704CFT/V
• Description: AMC97 Audio and Modem Codec
• Manufacturer: Wolfson Microelectronics plc

Production Data
MASTER/SLAVE ID0/1 SUPPORT
WOLFSON MICROELECTRONICS LTD
Table 4 Gain Control Register Location Versus Mode and ID
WM9704M 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 ID 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 Rev 2.1 specification defines that the ID 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.
Table 5 ID Selection
WM9704M supports the AMAP function whereby selection of an ID will automatically map the data
from the interface onto the PCM DACs.
Table 6 Default Slot to DAC Mappings Based on Codec ID
Front DAC
PGA
Rear DAC
PGA
Front Mixer
Rear Mixer
Front
Volume
Rear
Volume
The codec ID is available to the controller via registers 28h and 3c, bits D15 and D14
CODEC
PIN46 CID1
PGA
ID
Ground
Ground
00
01
NC
NC
PCM left DAC uses
10
11
10
11
10
11
10
11
10
11
10
11
0x
0x
0x
0x
0x
0x
data from slot #
ID
PIN45 CID0
Ground
Ground
CONTROL
NC
NC
3
3
AC–LINK FRAME DATA
REG
18h
70h
72h
74h
02h
38h
36h
04h
USED FOR DACS
REV 2.1 MODE (00)
Muted (bit15) Rev 2.1
ID SELECTED
Permanently muted
AND with 38h,7,15
AND with 36h,7,15
Not-muted (bit15)
muted (7 and 15)
muted (7 and 15)
PCM right DAC uses
MUTE DEFAULT
and powered off
switch enabled
Muted (bit15)
Muted (bit15)
data from slot #
Muted (15)
00
01
10
11
4
4
MASTER OR SLAVE
CONTROL
COMMENTS
Original definition (master)
Original definition (docking)
Master
REG
18h
70h
72h
74h
02h
38h
36h
04h
Slave
Slave
Slave
MODEM MODE (11)
PD Rev 3.2 January 2001
Permanently muted
AND with 38h,7,15
AND with 36h,7,15
AND with 04h, 15
Not-muted (bit15)
muted (7 and 15)
muted (7 and 15)
MUTE DEFAULT
Muted (bit 15)
Muted (bit15)
Muted (15)
WM9704M
BITCLK
Output
Input
Input
Input
15