saa7392 NXP Semiconductors, saa7392 Datasheet - Page 33

• Manufacturer Part Number: saa7392
• Description: Channel Encoder/decoder Cdr60
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.8.2
The digital audio output consists of 32-bit words (subframes) transmitted in biphasemark code (two transitions for a
logic 1 and one transition for a logic 0). Words are transmitted in blocks of 384.
Table 61 Digital audio output subframe format
Table 62 Channel status bit assignment
2000 Mar 21
0 to 3
4 to 7
8 to 27
28
29
30
31
0 to 4
5 to 7
8 to 15
28 to 29
16 to 27,
30 to 191
Channel encoder/decoder CDR60
BIT
BIT
F
ORMAT
sync
auxiliary
audio sample
validity flag
user data
channel status
parity bit
control
reserved mode always zero
category code
clock accuracy
remaining
FIELD NAME
FIELD NAME
The sync word is formed by violation of the biphase rule and therefore does not
contain any data. Its length is equivalent to 4 data bits. The 3 different sync patterns
indicate the following situations:
These bits are not used; normally zero.
Left and right samples are transmitted alternately. The first 4 bits not used (always
zero); 2’s compliment; LSB = bit 12 and MSB = bit 27.
If validity flag = 1, audio samples are flagged if an error has been detected but was
uncorrectable. This flag remains the same even if data is taken after concealment.
Subcode bits Q until W from the subcode section are transmitted via the user data
bit. This data is asynchronous with the block rate.
The channel status bit is the same for left and right words. Therefore, a block of
384 words contains 192 channel status bits. The category code is always CD. The bit
assignment is shown in Table 62.
Even parity for bits 4 to 30.
Bits 1 to 4 copied from register Output2. Bit 2 is logic 1 when copy permitted. Bit 3 is
logic 1 when recording has pre-emphasis
CD: bit 8 = logic 1, all other bits = logic 0
set by register Output2:
always zero
Sync B: Start of a block (384 words), word contains left sample
Sync M: Word contains left sample (no block start)
Sync W: Word contains right sample.
10 = level I
00 = level II
01 = level III
33
DESCRIPTION
DESCRIPTION
Preliminary specification
SAA7392