PMC-Sierra PM5349

S/UNI-QUAD

PMC-Sierra, Inc.

PM5349 S/UNI-QUAD

DATASHEET

PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)

Proprietary and Confidential to PMC-Sierra, Inc., and for its Custo mers’ Internal Use 151

Bit Type Function Default

Bit 7 R/W TPTYP 0

Bit 6 R/W TCALEVEL0 0

Bit 5 R/W Reserved 0

Bit 4 R/W Reserved 0

Bit 3 R/W HCSB 0

Bit 2 R/W HCSADD 1

Bit 1 R/W DSCR 0

Bit 0 R/W FIFORST 0

FIFORST:

The FIFORST bit is used to reset the four cell transmit FIFO. When FIFORST

is set to logic zero, the FIFO operates normally. When FIFORST is set to logic

one, the FIFO is immediately emptied and ignores writes. The FIFO remains

empty and continues to ignore writes until a logic zero is written to FIFORST.

Null/unassigned cells are transmitted until a subsequent cell is written to the

FIFO.

DSCR:

The DSCR bit controls the scrambling of the cell payload. When DSCR is a

logic one, cell payload scrambling is disabled. When DSCR is a logic zero,

payload scrambling is enabled.

HCSADD:

The HCSADD bit controls the addition of the coset polynomial, x6+x4+x2+1,

to the HCS octet prior to insertion in the synchronous payload envelope.

When HCSADD is a logic one, the polynomial is added, and the resulting

HCS is inserted. When HCSADD is a logic zero, the polynomial is not added,

and the unmodified HCS is inserted. HCSADD takes effect unconditionally

regardless of whether a null/unassigned cell is being transmitted or whether

the HCS octet was read from the FIFO.

HCSB:

The active low HCSB bit enables the internal generation and insertion of the

HCS octet into the transmit cell stream. When HCSB is logic zero, the HCS is

generated and inserted internally. If HCSB is logic one , then no HCS octet is

inserted in the transmit data stream.