PMC-Sierra, Inc.
PM5356
S/UNI-622-MAX
DATASHEET
S/UNI-622-MAX
PMC-1980589
ISSUE 5
SATURN USER NETWORK INTERFACE (622-MAX)
Pin Name
Type
Pin
No.
Function
TCA
Output
L23
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 set to one, two, three
or four cells. Note that regardless of what fill level TCA is set to
indicate "full" at, the transmit cell processor can store 4 complete
cells.
In 16-bit Level 2 ATM mode, TCA will transition low one TFCLK
cycle after the payload word 19 or 23 (depending of the
configuration in TXCP) is sampled on the TDAT[15:0] bus.
In 8-bit Level 3 ATM mode, TCA will transition low on the rising
edge of TFCLK before the payload byte 45 is sampled on the
TDAT[7:0] bus.
TCA is updated on the rising edge of TFCLK.
RFCLK
Input
M21
The UTOPIA receive FIFO read clock (RFCLK). RFCLK is used
to read ATM cells from the four cell receive FIFO.
When in 16-bit Level 2 ATM mode, RFCLK must cycle at a 50
MHz to 40 MHz instantaneous rate, and must be a free running
clock (cannot be gapped).
When in 8-bit Level 3 ATM mode, RFCLK must cycle at a 100
MHz to 60 MHz instantaneous rate, and must be a free running
clock (cannot be gapped).
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
26
PMC [ PMC-SIERRA, INC ]
