PM7346 Datasheet, PDF (111/419 Pages) PMC-Sierra, Inc – SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3

DATASHEET
PMC-960835
ISSUE 6
PM7346 S/UNI-QJET
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
LLOOP:
The LLOOP bit controls the line loopback. When a logic 0 is written to
LLOOP, line loopback is disabled. When a logic 1 is written to LLOOP, the
stream received on RPOS/RDATI and RNEG/RLCV/ROHM is looped to the
TPOS/TDATO and TNEG/TOHM outputs. Note that the TPOS, TNEG, and
TCLK outputs are referenced to RCLK when LLOOP is logic 1.
LOOPT:
The LOOPT bit selects the transmit timing source. When a logic 1 is written
to LOOPT, the transmitter is loop-timed to the receiver. When loop timing is
enabled, the receive clock (RCLK) is used as the transmit timing source. The
transmit nibble stuffing is derived from the nibble stuffing in the receive PLCP
frame (for DS3 or E3 PLCP frame transmission). The FIXSTUFF bit must be
set to logic 0 if the LOOPT bit is set to logic 1. When a logic 0 is written to
LOOPT, the transmit clock (TICLK) is used as the transmit timing source. The
nibble stuffing is derived from the REF8KI input, or is fixed internally (as
determined by the FIXSTUFF bit in the SPLT Configuration Register (for DS3
or E3 PLCP frame transmission only). Setting the LOOPT bit disables the
effect of the TICLK and TXREF bits in the S/UNI-QJET Transmit Configuration
and S/UNI-QJET Configuration 2 registers respectively, thereby forcing flow-
through timing.
FRMRONLY:
The FRMRONLY bit controls whether the S/UNI-QJET is operating solely as a
DS3, E3, or J2 framer/transmitter. If FRMRONLY is set to logic 1, the PLCP,
and ATM blocks are disabled and the RDATO, REF8KO/RFPO/RMFPO,
RSCLK, ROVRHD, TFPO/TMFPO, TFPI/TMFPI, and TDATI I/O pins are
enabled. The ATM interface inputs are ignored and the outputs are tri-stated.
If FRMRONLY is set to logic 0, the PLCP and ATM blocks are enabled and
the LCD, RPOH, RPOHCLK, RPOHFP, TPOH, TIOHM, and TPOHFP I/O pins
are enabled and the ATM interface inputs and outputs are enabled.
TOCTA:
The TOCTA bit enables octet-alignment or nibble-alignment of the transmit
cell stream to the transmission overhead when the arbitrary transmission
format is chosen (TFRM[1:0] = 11 binary and SPLT Configuration register bit
EXT = 1). This bit has no effect when DS3, G.751 E3, G.832 E3, J2, T1, or
E1 formats are selected since octet or nibble alignment is specified for these
formats. When the arbitrary transmission format is chosen and TOCTA is set
to logic 1, the ATM cell nibbles or octets are aligned to the arbitrary
transmission format overhead boundaries (as set by the TIOHM input).
Nibble alignment is chosen if the FORM[1:0] bits in the SPLT Configuration
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND ITS CUSTOMERS’ INTERNAL USE 90