cs8413-cs Cirrus Logic, Inc., cs8413-cs Datasheet - Page 25

• Manufacturer Part Number: cs8413-cs
• Description: 96 Khz Digital Audio Receivers
• Manufacturer: Cirrus Logic, Inc.

upon the C0 professional/consumer bit. The infor-
mation reported is shown in Table 7.
Professional Channel Status (C0 = 0)
When C0 is low, the received channel status block
is encoded according to the professional/broadcast
format. The Ca through Ce pins are defined for
some of the more important professional bits. As
listed in Table 7, Ca is the inverse of channel status
bit 1. Therefore, if the incoming channel status bit
1 is 1, Ca, defined as C1, will be 0. C1 indicates
whether audio (C1 = 1) or non-audio (C1 = 0) data
is being received. Cb and Cc, defined as EM0 and
EM1 respectively, indicate emphasis and are en-
coded versions of channel status bits 2, 3, and 4.
The decoding is listed in Table 8. Cd, defined as
C9, is the inverse of channel status bit 9, which
gives some indication of channel mode. (Bit 9 is
also defined as bit 1 of byte 1.) When Ce, defined
as CRCE, is low, the CS8414 calculated CRC value
does not match the received CRC value. This signal
may be used to qualify Ca through Cd. If Ca
through Ce are being displayed, Ce going low can
indicate not to update the display.
DS240F1
EM1 EM0 C2 C3 C4
0
0
1
1
Pin
C0
Ca
Cb
Cd
Ce
Cc
0
1
0
1
Table 7. Channel Status Pins
1
1
1
0
Table 8. Emphasis Encoding
1
1
0
0
Professional
1
0
0
0
0 (low)
CRCE
EM0
EM1
C1
C9
CCITT J.17 emphasis
50/15 s emphasis
No Emphasis
Not Indicated
Emphasis
Consumer
1 (high)
IGCAT
ORIG
C1
C2
C3
Consumer Channel Status (C0 = 1)
When C0 is high, the received channel status block
is encoded according to the consumer format. In
this case Ca through Ce are defined differently as
shown in Table 7. Ca is the inverse of channel sta-
tus bit 1, C1, indicating audio (C1 = 1) or non-audio
(C1 = 0). Cb is defined as the inverse of channel
status bit 2, C2, which indicates copy inhibit/copy-
right information. Cc, defined as C3, is the empha-
sis bit of channel status, with C3 low indicating the
data has had pre-emphasis added.
The audio standards, in consumer mode, describe
bit 15, L, as the generation status which indicates
whether the audio data is an original work or a copy
(1st generation or higher). The definition of the L
bit is reversed for three category codes: two broad-
cast codes, and laser-optical (CD’s). Therefore, to
interpret the L bit properly, the category code must
be decoded. The CS8414 does this decoding inter-
nally and provides the ORIG signal that, when low,
indicates that the audio data is original over all cat-
egory codes.
SCMS
The consumer audio standards also mention a serial
copy management system, SCMS, for dealing with
copy protection of copyrighted works. SCMS is de-
signed to allow unlimited duplication of the origi-
nal work, but no duplication of any copies of the
original. This system utilizes the channel status bit
2, Copy, and channel status bit 15, L or generation
status, along with the category codes. If the Copy
bit is 0, copyright protection is asserted over the
material. Then, the L bit is used to determine if the
material is an original or a duplication. (As men-
tioned in the previous paragraph, the definition of
the L bit can be reversed based on the category
codes.) There are two category codes that get spe-
cial attention: general and A/D converters without
C or L bit information. For these two categories the
SCMS standard requires that equipment interfacing
to these categories set the C bit to 0 (copyright pro-
CS8413 CS8414
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