CS4299-BQZR Cirrus Logic Inc, CS4299-BQZR Datasheet - Page 13

• Manufacturer Part Number: CS4299-BQZR
• Description: IC AC97 Codec With SRC
• Manufacturer: Cirrus Logic Inc

DS319-BQPP2
3. AC LINK FRAME DEFINITION
The AC-link is a bidirectional serial port with data
organized into frames consisting of one 16-bit and
twelve 20-bit time-division multiplexed slots. The
first slot, called the tag slot, contains bits indicating
if the CS4299-BQ is ready to receive data (input
frame) and which, if any, other slots contain valid
data. Slots 1 through 12 contain audio or con-
trol/status data. Both the serial data output and in-
put frames are defined from the controller
perspective, not from the CS4299-BQ perspective.
The controller synchronizes the beginning of a
frame with the assertion of the SYNC signal.
Bit Frame Position:
SDATA_OUT
Bit Frame Position:
SDATA_IN
BIT_CLK
SYNC
F255
F255
81.4 ns
GPIO
INT
0
Frame
Codec
Ready
Valid
F0
F0
12.288 MHz
Slot 1
Slot 1
Valid
Valid
F1
F1
Slot 2
Slot 2
Valid
Valid
F2
F2
Tag Phase
Slot 0
Slot 12
Slot 12
Figure 9. AC-link Input and Output Framing
F12
Valid
F12
Valid
F13
F13
0
0
Codec
F14
F14
ID1
0
Codec
F15
F15
ID0
0
F16
R/W
F16
(48 kHz)
20.8 µs
0
Slot 1
Figure 9 shows the position of each bit location
within the frame. The first bit position in a new se-
rial data frame is F0 and the last bit position in the
serial data frame is F255. When SYNC goes active
(high) and is sampled active by the CS4299-BQ (on
the falling edge of BIT_CLK), both devices are
synchronized to a new serial data frame. The data
on the SDATA_OUT pin at this clock edge is the
final bit of the previous frame’s serial data. On the
next rising edge of BIT_CLK, the first bit of Slot 0
is driven by the controller on the SDATA_OUT
pin. On the next falling edge of BIT_CLK, the
CS4299-BQ latches this data in, as the first bit of
the frame.
F35
F35
0
0
WD15
RD15
F36
F36
Slot 2
Data Phase
D19
D19
F56
F56
Slot 3
F57
D18
D18
F57
D19
D19
F76
F76
Slot 4
CS4299-BQ
CS4299-BQ
D19
D19
F96
F96
Slots 5-12
F255
F255
GPIO
INT
0
13
13