PMC-Sierra, Inc.
PRELIMINARY
PM5381 S/UNI-2488
DATASHEET
PMC-2000489
ISSUE 1
SATURN USER NETWORK INTERFACE FOR 2488 MBIT/S
Function
Pin Name
Type
Pin
No.
The POS-PHY transmit write enable (TENB) signal is an active
low input which is used to initiate writes to the transmit FIFO’s.
When TENB is sampled high, the information sampled on the
TDAT[31:0], TPRTY, TSOP, TEOP, TMOD[1:0], and TERR
signals are invalid. When TENB is sampled low, the information
sampled on the TDAT[31:0], TPRTY, TSOP, TEOP, TMOD[1:0],
and TERR signals are valid and are written into the transmit
FIFO.
TENB
TENB is sampled on the rising edge of TFCLK.
D17
The UTOPIA transmit cell available (TCA) signal provides
direct status indication of when cell space is available in the
transmit FIFO. When set high, TCA indicates that the
corresponding transmit FIFO is not full and a complete cell may
be written. TCA is set low to either indicate that the transmit
FIFO is near full or that the transmit FIFO is full. To reduce FIFO
latency, the FIFO depth at which TCA indicates "full" can be
configured. Note that regardless of what fill level TCA is set to
indicate "full" at, the transmit cell processors still have the full
capacity of its FIFO to store cells.
TCA
Output
TCA will transition low one TFCLK cycle after the payload word
7 or 11 (depending of the configuration) is sampled on the
TDAT[31:0] bus.
TCA is updated on the rising edge of TFCLK.
Proprietary and Confidentail to PMC-Sierra Inc., and for its Customer’s Internal Use
35
PMC [ PMC-SIERRA, INC ]
