saa7372 NXP Semiconductors, saa7372 Datasheet - Page 13

• Manufacturer Part Number: saa7372
• Description: Digital Servo Processor And Compact Disc Decoder Cd7
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.6
The SAA7372 has a 8 frame FIFO. The error corrector is
a t = 2, e = 4 type, with error corrections on both C1
(32 symbol) and C2 (28 symbol) frames. Four symbols are
used from each frame as parity symbols. This error
corrector can correct up to two errors on the C1 level and
up to four errors on the C2 level.
The error corrector also contains a flag processor. Flags
are assigned to symbols when the error corrector cannot
ascertain if the symbols are definitely good. C1 generates
output flags which are read after (de-interleaving) by C2,
to help in the generation of C2 output flags.
The C2 output flags are used by the interpolator for
concealment of uncorrectable errors. They are also output
via the EBU signal (DOBM) and the EF output with I
for CD ROM applications.
1998 Feb 26
Digital servo processor and Compact Disc
decoder (CD7)
n = disc speed
n = disc speed.
handbook, full pagewidth
FIFO and error corrector
W96
F8
33.9/n s
200/n s
min
Fig.8 Subcode format and timing on pin V4.
11.3/n
1
F1
s
11.3/n
Fig.9 Flag output timing diagram.
Q
s
F2
R
F3
2
S-bus
S
F4
13
T
F5
7.6.1
The flags output pin CFLG (open-drain) shows the status
of the error corrector and interpolator and is updated every
frame (7.35
present on the CFLG pin as illustrated in Fig.9. This signal
shows the status of the error corrector and interpolator.
The first flag bit, F1, is the absolute time sync signal, the
FIFO-passed subcode sync and relates the position of the
subcode sync to the audio data (DAC output). This flag
may also be used in a super FIFO or in the synchronization
of different players. The output flags can be made
available at bit 4 of the EBU data format (LSB of the 24-bit
data word), if selected by register A.
U
F6
V
F7
F
LAGS OUTPUT
W
F8
n kHz). In the SAA7372 chip a 1-bit flag is
11.3/n s min
90/n s max
33.9/n s
(CFLG)
MBG425
1
F1
MBG401
Q
Product specification
SAA7372