PM5347S Datasheet, PDF (267/302 Pages) PMC-Sierra, Inc – SATURN USER NETWORK INTERFACE PLUS

PM5347 S/UNI-PLUS
DATA SHEET
PMC-941033
ISSUE 6
SATURN USER NETWORK INTERFACE PLUS
The Transmit Synchronous FIFO Timing Diagram (Figure 34) illustrates the
operation of the drop side transmit interface. The S/UNI-PLUS indicates that
there is space available in the transmit FIFO by asserting the transmit cell
available output, TCA. TCA remains high until the transmit FIFO is almost full,
full or if an error condition is detected. Almost full implies that the transmit FIFO
can accept at most an additional four writes. Selection between almost full and
full is made using the TACP FIFO Control register. If TCA is asserted high and
the downstream is ready to write a word, the downstream device should assert
TWRENB low. At anytime, if the downstream does not have a word to write, it
can deassert TWRENB.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE 251