PMC-Sierra, Inc.
PRELIMINARY
PM5381 S/UNI-2488
DATASHEET
PMC-2000489
ISSUE 1
SATURN USER NETWORK INTERFACE FOR 2488 MBIT/S
normally in the transmit direction. When PDLE is logic zero, the S/UNI-2488 operates
normally.
LOOPT:
The LOOPT bit selects the source of timing for the transmit section of the channel. When
LOOPT is a logic zero, the transmitter timing is derived from input REFCLK (Clock Synthesis
Unit). When LOOPT is a logic one, the transmitter timing is derived from the recovered clock
(Clock Recovery Unit).
The S/UNI-2488 cannot be configured for loop time operation if operating with a mate device
unless both the received clocks are frequency locked.
MODE[1:0]:
The MODE bits selects one of the four operating mode of the S/UNI-2488 as illustrated
below:
Description
MODE[1:0]
00
Normal operation. The S/UNI-2488 is configured in this mode when
not using the APS ports. When using the APS ports, the S/UNI-
2488 is configured in this mode if a failover condition does not exist.
Under this mode of operation, the S/UNI-2488 receives data from
RXD+/- and outputs this data though its POS-PHY Level 3 interface
and transmits data from its POS-PHY Level 3 interface out through
TXD+/-.
Reserved
01
10
APS Working Mate under a failed condition. The S/UNI-2488 can
be configured in this mode when operating as the working device in
a APS failover condition.
Under this mode of operation, the S/UNI-2488 receives a SONET
stream from a protect mate via the Input APS port and presents the
payload out through the POS-PHY Level 3 interface. The S/UNI-
2488 transmits data from its POS-PHY Level 3 interface out
thorough its Output APS port to a mate device. It is assumed that
the mate device will transmit the data onto the line.
APS Protect Mate. The S/UNI-2488 is always configured in this
mode as a protect device.
11
Under this mode of operation, the Input APS port is expected to
contain a bridged transmit SONET stream from a working mate
device. In addition, the S/UNI-2488 will output a received SONET
stream out the Output APS port to the same mate device.
Proprietary and Confidentail to PMC-Sierra Inc., and for its Customer’s Internal Use
100
PMC [ PMC-SIERRA, INC ]
