Cirrus Logic AN22 - Manual (Page 8)

AN22
8 AN22REV2
source has copy protection asserted, then the L bit
must be used to determine whether the data can be
recorded.
The L bit determines whether the source is an orig-
inal (or prerecorded) work, or is a copy of an orig-
inal work (first generation or higher). The actual
meaning of the L bit can only be determined by
looking at the category code since certain category
codes reverse the meaning.
If the category code is CD (1000000) and the copy
bit alternates at a 4 to 10Hz rate, the CD is a copy
of an original work that has copy protection assert-
ed and no recording is permitted.
BYTE 1 - Category Code 101
bits 3 4 5 6 Musical Instruments, mics, etc.
*
0 0 0 0 Synthesizer
* 1 0 0 0 Microphone
X X X X All other states are reserved
BYTE 2
bits 0 1 2 3 Source Number
0 0 0 0 Unspecified
1 0 0 0 1
0 1 0 0 2
1 1 0 0 3
0 0 1 0 4 to
0 1 1 1 14 (binary - 0 is LSB, 3 is MSB)
1 1 1 1 15
bit 4 5 6 7 Channel Number
0 0 0 0 Unspecified
1 0 0 0 A (Left in 2 channel format)
0 1 0 0 B (Right in 2 channel format)
1 1 0 0 C to
0 1 1 1 N (binary - 4 is LSB, 7 is MSB)
1 1 1 1 O
BYTE 1 - Category Code 110
bits 3 4 5 6 Magnetic tape or disk
0 0 0 0 DAT
* 1 0 0 0 Digital audio sound VCR
X X X X All other states are reserved
BYTE 3
bits 0 1 2 3 Fs: Sample Frequency
0 0 0 0 44.1 kHz
0 1 0 0 48 kHzr
1 1 0 0 32 kHz
1 1 0 0 Sample-rate converter
X X X X All other states are reserved
bits 4 5 Clock Accuracy
0 0 Level II, ±1000 ppm (default)
0 1 Level III, variable pitch
1 0 Level I, ±50 ppm - high accuracy
1 1 Reserved
bits 6 7
X X Reserved
BYTE 4 - 23
Reserved
* Data from draft of IEC 958 proposed amendment (from TC84). Has not recieved approval yet.
Table 5. Consumer Channel Status Bytes 1-23