Cirrus Logic AN22 - Manual (Page 6)

AN22
6 AN22REV2
Channel Status Block - Consumer Format
Setting the first bit of channel status low designates
the consumer format. The channel status block
structure for the consumer format is illustrated in
Figure 6 with the bit descriptions in Tables 4 and 5.
All areas listed as "reserved" must be transmitted as
a 0. The data for this format was obtained from the
EIAJ CP-340 and the IEC958 with some informa-
tion from TC84 which is a proposed amendment to
IEC958 and has not received approval yet. As with
the professional format, since this format is cur-
rently changing, the accuracy of the data listed can-
not be guaranteed.
In the consumer format, bit 0 must be 0. If bit 1 is
set to 1 defining the data as non-audio, then bits 3-5
are redefined (see Table 4, byte 0). Bits 6 and 7 of
byte 0 define the mode, and only one mode is pres-
ently defined, mode = 00. This mode defines the
next three bytes as listed in Figure 6. Most of byte 1
defines the category code. The first 3 to 5 bits de-
fine the general category. Under the laser-optical
category is compact disk (cat. code 1000000). This
format defines some of the Uchannel bits and the
CD subcode port. More information can be ob-
tained from the CP-340 or IEC958 documents.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Reserved
0 1 2 3 4 5 6 7
byte/bit
block
bit
7
15
23
31
39
191
PRO=0 Audio Emphasis Mode
Category Code
Source Num. Channel Num.
Fs
Copy
L
Clock Acc. Reserved
Figure 6. Consumer Channel Status Block Structure