AK4545 Datasheet, PDF (19/33 Pages) Asahi Kasei Microsystems – AC97 AUDIO CODEC WITH SRC AND DIT

[ASAHI KASEI]
c) The Detail of S/PDIF specification
The AK4545 uses two times of bit rate clock, and use bi-phase method except of preamble.
[Architecture of S/PDIF]
Frame formant of S/PDIF is the follwoing.
- One frame consists of two sub-frames.
- One block consists of 192 frames.
- Preamble(B, M, W) for synchronization is added. ( see the following figure.)
M Channel 1 W
Channel2
B Channel 1 W Channel 2 M
sub-frame
sub-frame
[AK4545]
Channel 1
Frame 191
Frame 0
Frame 1
Preamble
B
M
W
Channel Coding
Preceding symbol : ”0”
Preceding symbol : ”1”
1110100000010111
1110001000011101
1110010000011011
Definition of sub-frame( note that audio data format is LSB first)
bit
0
3
78
L
Contents Preamble
0000S
B
27 28 29 30 31
M
SV U C P
B
V: Valid bit : outputs D15 bit of 70h register
U: User bit : always outputs “0”
C: Channel Status bit (refer to 72h, 74h registers. The AK4545 outputs the contents of 72h and 74h registers one
bit per frame. The AK4545 outputs “0” from 33 frame to 191 frame.)
P: Parity bit
note that VUC bits of channel 2 are the same as the ones of Channel 1
items
PRO/consumer
AUDIO#
Copy/Copyright
Pre-emphasis
Mode
Category CODE
L:Generation Status
Source Num.
Channel Num
Sample Frequency
Clock Accuracy
Reserved
Bits
0
1
2
3
4-5
6-7
8-14
15
16-19
20-23
24-27
28-29
30-191
Channel Status bits
fixed
Register
Register
Register
fixed
fixed
Register
Register
fixed
fixed
Register
fixed
fixed
“ 0” (consumer mode only )
72h D1
72h D2
72h D3
00
00
72h D8-D14
72h D15
0000
0000
74h D8-D11
00
All 0
Validity Bit : can be set by D15 bit in 70h register
User Data : all 0
MS0058-E-00
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2000/11