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Bit
Channel #A
S/UNI-8x155 ASSP Telecom Standard Product Data Sheet
Released
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC- 2010299, Issue 2
398
Because of the architecture of the receive APS interface, the reference clocks REFCLK for both
the DRU cannot process serial interfaces with a frequency offset from the 622.08 MHz clock
synthesized by the CSU block.
The RAOP and SIPO blocks perform SONET framing, BIP calculation and performance
monitoring. The DCC channel is used carry transport alarm status (LOS, LOF and LAIS) of the
path streams in order for the AUTOPRDI logic to quickly respond to these alarms. While the
transport alarm status is not necessary to generate correct PRDI in the transmit direction, the
transport alarm status allows the AUTOPRDI to quickly report PRDI without waiting numerous
SONET frames for the receive RPOP to declare path failure. LOP is required to be propagated
through the APS link as LOP, then the software workaround is to set the DLOP bit in the STAL
Block. See STAL Channel #0 to #7 Control and Interrupt Status for more details.
The recommanded APS initialization and switching sequence is as follows:
1. Set all H4BYP bits ( need be set only once after a device reset).
2. Start external APS configuration on all 4 channels
3. Place the channel and APS FIFOs in reset
4. Reset RAPS FIFOs (ensure FIFOs are centered)
5. Place all the Level 2 and Level 3 TX and RX FIFOs in reset
6. Write to the APS configuration registers to configure cross bars as required.
7. Configure the transmit path of the working device to go out the APS links
8. Set the protection TX interface to source from the APS channel specified in the TX
parameter. (0x84 sets the TXEN and TSEL[2] bits and keeps PRCOM cleared on the
protection device)
9. Set the working RX interface to source from the APS channel specified in the RX
parameter. (x085 sets RXEN and RSEL[2] bits high)
10. Take the channel and APS FIFO out of reset.
11. Take all Level 2 and Level 3 TX and RX FIFOs out of reset
The following tables describes basic programming requirements for various configurations.
Table 21 Channel Swizzle Configuration
Channel #B
RXEN
1
1
RSEL[4:0]
Device channel B
Device channel A
TXEN
1
1