Rainbow Electronics AT91CAP9S250A - Manual (Page 621)

621
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
37.6 Functional Description
37.6.1 Protocol overview
AC-link protocol is a bidirectional, fixed clock rate, serial digital stream. AC-link handles multi-
ple input and output Pulse Code Modulation PCM audio streams, as well as control register
accesses employing a Time Division Multiplexed (TDM) scheme that divides each audio frame
in 12 outgoing and 12 incoming 20-bit wide data slots.
Figure 37-3. Bidirectional AC-link Frame with Slot Assignment
Slot #
AC97FS
TAG
CMD
ADDR
CMD
DATA
0
AC97TX
(Controller Output)
AC97RX
(Codec output)
PCM
L Front
PCM
R Front
LINE 1
DAC
PCM
Center
PCM
R SURR
PCM
LFE
LINE 2
DAC
HSET
DAC
IO
CTRL
TAG
STATUS
ADDR
STATUS
DATA
PCM
LEFT
LINE 1
DAC
PCM
MIC
RSVED RSVED RSVED
LINE 2
ADC
HSET
ADC
IO
STATUS
1 2 3 4 5 6 7 8 9 10 11 12
PCM
L SURR
PCM
RIGHT
Table 37-2. AC-link Output Slots Transmitted from the AC’97C Controller
Slot # Pin Description
0 TAG
1 Command Address Port
2 Command Data Port
3,4 PCM playback Left/Right Channel
5 Modem Line 1 Output Channel
6, 7, 8 PCM Center/Left Surround/Right Surround
9 PCM LFE DAC
10 Modem Line 2 Output Channel
11 Modem Handset Output Channel
12 Modem GPIO Control Channel
Table 37-3. AC-link Input Slots Transmitted from the AC’97C Controller
Slot # Pin Description
0 TAG
1 Status Address Port
2 Status Data Port
3,4 PCM playback Left/Right Channel
5 Modem Line 1 ADC
6 Dedicated Microphone ADC
7, 8, 9 Vendor Reserved