WM9704CFT/V Wolfson Microelectronics plc, WM9704CFT/V Datasheet - Page 17

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

Production Data
AC-LINK DIGITAL SERIAL INTERFACE PROTOCOL
Figure 8 AC’97 Standard Bi-directional Audio Frame
Figure 9 AC-link Audio Output Frame
WOLFSON MICROELECTRONICS LTD
SDATA_OUT
SDATA_OUT
SDATA_IN
BIT_CLK
NUMBER
SYNC
SYNC
SLOT
END OF PREVIOUS
AUDIO FRAME
CODEC ID
SLOTREQ 3-12
TAG
TAG
0
FRAME
VALID
12.288MHz
TAG PHASE
SLOT(1)
STATUS
The WM9704M 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 WM9704M provides support for 18-bit operation.
ADDR
CMD
ADR
1
SLOT(2)
(’1’ = TIME SLOT CONTAINS
81.4nS
TIME SLOT ’VALID’ BITS
STATUS
VALID PCM DATA)
DATA
DATA
CMD
2
SLOT(12)
LEFT
LEFT
PCM
PCM
3
’0’
(ID1)
RIGHT
RIGHT
PCM
PCM
4
(ID0)
LINE 1
LINE 1
DAC
ADC
5
19
SLOT (1)
CENTRE
PCM
ADC
MIC
6
0
L SURR
RSRVD
19
PCM
20.8 S (48kHz)
DATA PHASE
7
SLOT (2)
R SURR
RSRVD
PCM
8
0
19
RSRVD
PCM
LFE
SLOT (3)
9
LINE 2
LINE 2
PCM L
(n+1)
DAC
ADC
0
10
PCM R
HSET
HSET
PD Rev 3.2 January 2001
(n+1)
DAC
ADC
11
19
SLOT (12)
WM9704M
STATUS
PCM C
CTRL
(n+1)
12
IO
IO
0
17