WM9707_06 WOLFSON [Wolfson Microelectronics plc], WM9707_06 Datasheet - Page 17

• Manufacturer Part Number: WM9707_06
• Description: AC 97 Revision 2.1 Audio CODEC with SPDIF Output
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM9707
MASTER/SLAVE ID SUPPORT
CONTROL INTERFACE
AC-LINK DIGITAL SERIAL INTERFACE PROTOCOL
Figure 11 AC’97 Standard Bi-Directional Audio Frame
w
TAG PHASE
SDATAOUT
NUMBER
SLOT
SYNC
CODEC ID
WM9707 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 pin 45 on the package.
Fundamentally, a device identified as a master (ID = 0) 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 pin has inverting sense, and are provided
with internal weak pull ups. Therefore, if no connections are made to the CID pin, then the pin pulls hi
and an ID = 0 is selected, i.e. master. External connects to ground will select other IDs.
Table 3 ID Selection
A digital interface has been provided to control the WM9707 and transfer data to and from it. This
serial interface is compatible with the Intel AC’97.
The main control interface functions are:
The WM9707 incorporates a 5-pin digital serial interface that links it to the AC’97 controller. AC-link
is a bi-directional, fixed rate, serial PCM digital stream. It handles multiple input and output audio
streams, as well as control Register accesses employing a time division multiplexed (TDM) scheme.
The AC-link architecture divides each audio frame into 12 outgoing and 12 incoming data streams,
each with 20-bit sample resolution. With a minimum required DAC and ADC resolution of 16-bits,
AC’97 may also be implemented with 18 or 20-bit DAC/ADC resolution, given the headroom that the
AC-link architecture provides. The WM9707 provides support for 18-bit operation.
PIN 45 CID
SLOTREQ 3-12
TAG
TAG
0
Ground
Control of analogue gain and signal paths through the mixer
Bi-directional transfer of ADC and DAC words to and from AC’97 controller
Selection of Powerdown down modes.
NC
STATUS
ADDR
CMD
ADR
1
STATUS
DATA
DATA
CMD
2
SELECTED
LEFT
LEFT
PCM
PCM
3
ID
0
1
RIGHT
RIGHT
PCM
PCM
4
RSRVD
RSRVD
5
MASTER OR
SLAVE
Master
DATA PHASE
Slave
CENTRE
RSRVD
PCM
6
RSRVD
L SURR
PCM
7
R SURR
RSRVD
PCM
8
RSRVD
PCM
LFE
BITCLK
9
Output
Input
RSRVD
RSRVD
PCM L
(n+1)
10
PD Rev 4.1 June 2006
RSRVD
RSRVD
PCM R
(n+1)
11
Production Data
RSRVD
RSRVD
PCM C
(n+1)
12
17