ort8850 Lattice Semiconductor Corp., ort8850 Datasheet - Page 38

• Manufacturer Part Number: ort8850
• Description: Field-programmable System Chip Fpsc Eight-channel X 850 Mbits/s Backplane Transceiver
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
violated a per channel alarm bit will be set indicating that this channel has exceeded the threshold, as well as a
FIFO out-of-sync alarm bit to indicate the channel is not longer in sync with the reset of the alignment group.
The incoming data can be considered as 4 STS-12 channels (A, B, C, and D) per quad. Thus we have STS-12
channels AA to AD from quad A of the STM and STS-12 channels BA to BD of quad B. The 8 channels of parallel
SONET data can be grouped into an alignment group by 2, by 4 or all 8 channels. As the serial data is run through
the backplane and SERDES the parallel data can be slightly varied. The alignment FIFO can absorb this difference
in the channels and create a byte aligned grouping.
These streams can be frame aligned in the following patterns. Streams can be aligned on a twin STS-12 basis as
shown in Figure 18. In STS-48 mode, all four STS-12s of each STM quad are aligned with each other (i.e. AA, AB,
AC, AD) as shown in Figure 19. Optionally in STS-48 mode all eight STS-12s (STMs A and B) can be aligned which
allows hitless switching since all streams will be byte aligned (Figure 20). Multiple ORT8850 devices can be aligned
with each other using a common system frame pulse to enable STS-192 or higher modes.
Figure 18. Twin Channel Alignment
Figure 19. Alignment of SERDES Quads A and B
Channel AA
Channel AB
Channel BA
Channel BD
Channel AB
Channel BB
Channel AD
Channel AA
Channel BB
Channel AC
Channel BC
Channel BA
Channel BC
Channel AC
QUAD ALIGNMENT OF CHANNELS AA
QUAD ALIGNMENT OF CHANNELS BA
Channel BD
Channel AD
TWIN ALIGNMENT OF CHANNELS AA AND BA
TWIN ALIGNMENT OF CHANNELS AB AND BB
TWIN ALIGNMENT OF CHANNELS AC AND BC
TWIN ALIGNMENT OF CHANNELS AD AND BD
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,
,
AB
BB
,
,
AC
BC
Channel AB
Channel BB
,
,
Channel BA
AND AD
AND BD
Channel AA
Channel BC
Channel BD
Channel BA
Channel BB
Channel AC
Channel AA
Channel AB
Channel AD
Channel AC
Channel BC
Channel AD
Channel BD
t
3
t
2
t
ORCA ORT8850 Data Sheet
1
t
t
0
1
t
0