PM7345S Datasheet, PDF (137/306 Pages) PMC-Sierra, Inc – SATURN USER-NETWORK INTERFACE FOR ATM PLESIOCHRONOUS DIGITAL HIERARCHY DATACOM

DATA SHEET
PMC-931011
ISSUE 6
PM7345 S/UNI-PDH
SATURN USER-NETWORK INTERFACE
Register 2CH: SPLT Configuration
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Function
FORM[1]
FORM[0]
M1TYPE
M2TYPE
FIXSTUFF
PLCPEN
Unused
EXT
Default
0
0
0
0
0
0
X
0
EXT:
The EXT bit disables the internal transmission system sublayer timeslot counter
from identifying DS1, DS3, E1 or G.751 E3 overhead bits. The EXT bit allows
transmission formats that are unsupported by the internal timeslot counter to be
supported using the TIOHM input. When a logic 0 is written to EXT, input
transmission system overhead (for DS1, DS3, E1 and G.751 E3 formats) is
indicated using the internal timeslot counter. This counter flywheels to create the
appropriate transmission system alignment. This alignment is indicated on the
TNEG/TOHM output. When a logic 1 is written to EXT, indications on TIOHM
identify each transmission system overhead bit. These indications flow through
the S/UNI-PDH and appear on the TNEG/TOHM output where they mark the
transmission system overhead placeholder positions in the TPOS/TDAT stream.
The EXT bit must be set to logic 1 for G.832 E3 format.
PLCPEN:
The PLCPEN bit enables PLCP frame insertion. When a logic 1 is written to
PLCPEN, PLCP framing is inserted. The PLCP format is specified by the
FORM[1:0] bits in this register. When a logic 0 is written to PLCPEN, PLCP
related functions in the SPLT block are disabled. The PLCPEN bit must be set to
logic 0 for G.832 E3 format. When switching from transmission of PLCP
formatted cells to direct ATM, the S/UNI-PDH may transmit the bytes with the
nibbles swapped. This situation can be avoided if direct mode is selected by
doing a software reset (Bit 7 Register 04H) which forces the SUNI-PDH into the
default direct ATM mode.
FIXSTUFF:
The FIXSTUFF bit controls the transmit PLCP frame octet/nibble stuffing used for
DS3 and G.751 E3 PLCP frame formats. When a logic 0 is written to FIXSTUFF,
stuffing is determined by the C13/CADD input. When a logic 1 is written to
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