
PM7346 S/UNI-QJET
DATASHEET
PMC-960835
ISSUE 6
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND ITS CUSTOMERS’ INTERNAL USE
118
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 REF8KI input. When a logic 1 is
written to FIXSTUFF and the DS3 PLCP frame format is enabled, a nibble is
stuffed into the 13 nibble trailer twice every three stuff opportunities (i.e. 13,
14, 14 nibbles). This stuff ratio provides for a nominal PLCP frame rate of
125.0002366 μs (an error of 1.9 ppm). When the G.751 E3 PLCP frame
format is enabled, 18, 19 or 20 octets are stuffed into the trailer depending on
the alignment of the G.751 E3 frame, and the G.751 E3 PLCP frame. This
yields a nominal PLCP frame rate of 125 μs.
M2TYPE:
The M2TYPE bit selects the type of code transmitted in the M2 octet. These
codes are required in systems implementing the IEEE-802.6 DQDB protocol.
When a logic 0 is written to M2TYPE, the fixed pattern type 0 code is
transmitted in the M2 octet. When a logic 1 is written to M2TYPE, the 1023
cyclic code pattern (starting with B6 hexadecimal and ending with 8D
hexadecimal) is transmitted in the M2 octet. Please refer to TA-TSY-000772,
Issue 3 and Supplement 1, for details on the codes.
M1TYPE:
The M1TYPE bit selects the type of code transmitted in the M1 octet. These
codes are required in systems implementing the IEEE-802.6 DQDB protocol.
When a logic 0 is written to M1TYPE, the fixed pattern type 0 code is
transmitted in the M1 octet. When a logic 1 is written to M1TYPE, the 1023
cyclic code pattern (starting with B6 hexadecimal and ending with 8D
hexadecimal) is transmitted in the M1 octet. Please refer to TA-TSY-000772,
Issue 3 and Supplement 1, for details on the codes.
FORM[1:0]:
When EXT = 0 and PLCPEN = 0, the FORM[1:0] bits and the TFRM[1:0] bits
in the S/UNI-QJET Transmit Configuration register select the ATM direct-
mapped transmission frame format as shown below. When EXT = 0 and
PLCPEN = 1, the FORM[1:0] bits along with the TFRM[1:0] bits select the
transmission and PLCP frame format as shown below. When EXT = 1 and
TOCTA = 1, then the FORM[1:0] bits control the cell alignment with respect to
the transmission overhead given on TIOHM[x] as shown below. The FORM
bits have no effect if EXT = 1 and TOCTA = 0.