Cirrus Logic AN22 - Manual (Page 5)

AN22
AN22REV2 5
BYTE 2
bits 0 1 2 AUX: Use of auxiliary sample bits
0 0 0 Not defined. Maximum audio word length
is 20 bits
0 0 1 Used for main audio. Maximum audio
word length is 24 bits
0 1 0 Single coordination signal. Max. audio
word length is 20 bits
0 1 1 User defined application
X X X All other states of bits 4-7 are reserved.
bits
3 4 5
Source word length
Max. audio based on bits 0-2 above
Max audio 24 bits
Max audio 20 bits
0 0 0 Not Indicated Not Indicated
(default)
0 0 1 23 bits 19 bits
0 1 0 22 bits 18 bits
0 1 1 20 bits 16 bits
1 0 1 24 bits 20 bits
X X X All other states of bits 3-5 are reserved
bits 6 7
X X Reserved
BYTE 3
bits 0-7 Vectored target byte
XXXXXX Reserved
BYTE 4
bits
0 1
Digital audio reference signal per
AES11-1990
0 0 Not reference signal (default)
0 1 Grade 1 reference signal
1 0 Grade 2 reference signal
1 1 Reserved
bits 2 7
XXXXXX Reserved
BYTE 5
bits 0-7
XXXXXX Reserved
BYTE 6-9
Alphanumeric channel origin data
7-bit ISO 646 (ASCII) data with odd parity bit. First character
in message is byte 6. LSB’s are transmitted first.
BYTE 10-13
Alphanumeric channel destination data
7-bit ISO 646 (ASCII) data with odd parity bit. First character
in message is byte 10. LSB’s are transmitted first.
BYTE 14-17
Local sample address code (32-bit binary)
Value is of first sample of current block.
LSBs are transmitted first.
BYTE 18-21
Time-of-day sample address code (32-bit binary)
Value is of first sample of current block.
LSBs are transmitted first.
BYTE 22
bits 0 1 2 3
X X X Reserved
bit 4 Channel status bytes 0 to 5
0 Reliable
1 Unreliable
bit 5 Channel status bytes 6 to 13
0
1 Reliable
Unreliable
bit 6 Channel status bytes 14-17
0
1 Reliable
Unreliable
bit 7 Channel status bytes 18 to 21
0 Reliable
1 Unreliable
BYTE 23
CRCC: Cyclic redundancy check character
CRCC for channel status data block that uses bytes 0 to22
inclusive. Generating polynomial is
G(x) = X
8
+ X
4
+ X
3
+ X
2
+ 1
with an initial state of all ones
Table 3. Professional Channel Status Bytes 2-23.