L64704 LSI Logic Corporation, L64704 Datasheet - Page 99

• Manufacturer Part Number: L64704
• Description: Satellite Decoder Technical Manual 5/97
• Manufacturer: LSI Logic Corporation

4.5.2
Synchronization
Stage 3 Output
Figure 4.13
Synchronization
Stage 3 Output
Waveforms
(Pin FSTARTOUT)
4.5.3
Reed-Solomon
Decoder Output
(Pin ERROROUT)
(Pin DVALIDOUT)
S3_FSTARTOUT
S3_ERROROUT
S3_DVALIDOUT
(Pins CO[7:0])
S3_CO[7:0]
OCLK
Channel Output Mode, where the MSB is oldest, and the LSB is newest.
The FSTARTOUT strobe overlaps the first data byte. If BF is set (Group
4, APR 11), the L64704 provides BCLKOUT as an additional strobe that
has one rising and one falling edge per valid CO[7:0] data byte. The
L64704 asserts BCLKOUT in the middle of the decoded data bytes, so
the device that receives the output from the L64704 can latch data at the
BCLKOUT rate rather than at the OCLK rate. BCLKOUT is a continuous
clock output at 1/8 the OCLK frequency when BF is cleared, regardless
of whether data is present on the CO[7:0] bus.
You can observe the outputs of the synchronization stage preceding the
Descrambler by setting the OS[2:0] bits to 0b001.
Synchronization Stage 3 output signals. Signals prefixed by “S3_” are
driven on the pin indicated in parenthesis below the signal name.
In contrast to the Descrambler output, the CO[7:0] bus still carries
scrambled data.
You can observe the outputs of the Reed-Solomon decoder module by
setting the OS[2:0] bits to 0b010. This mode can also be used if you want
to bypass the Descrambler entirely.
Solomon Decoder output signals. Signals prefixed by “RS_” are driven
on the pin indicated in parenthesis below the signal name.
Data Path Output Configurations
Message Bytes
N = Code Word Length
Check Bytes
Figure 4.14
shows the Reed-
Figure 4.13
Gap
shows the
Message
4-15