Altera POS-PHY Level 2 and 3 Compiler - Manual (Page 38)

3–10 Chapter 3: Functional Description
Parameters
POS-PHY Level 2 and 3 Compiler User Guide © November 2009 Altera Corporation
Preliminary
Table 3–3. POS-PHY Level 3 FIFO Buffer Settings (Part 1 of 2)
Interface
(Direction) FIFO Threshold FIFO Burst FIFO Remote Burst
Link
Transmit
(Source) When each FIFO buffer overflows
the FIFO buffer threshold level, or
contains a packet or packet
fragment with an EOP, it triggers
its not empty flag. The interface
then tries to empty each of the FIFO
buffers containing data, as soon as
it detects the PHY transmit
interface has indicated it has space.
When operating in polled mode,
this is indicated using the PTPA
and STPA inputs. When operating
in direct status mode, this is
indicated using the DTPA inputs. Indicates the maximum
number of bytes the interface
transfers in each FIFO buffer
burst.
In MPHY mode, at the end of
each FIFO buffer burst the
MegaCore function re-
arbitrates for a new channel
in a round-robin fashion.
Set FIFO buffer burst <= FIFO
buffer threshold.
Not applicable in SPHY
mode.
Prevents the PHY transmit interface
from overflowing. Must be compatible
with the PHY transmit interface FIFO
buffer burst setting. When the interface
is in the process of transferring data
and the PHY transmit interface indicates
it is almost full, link transmit interface
transfers up to FIFO buffer remote burst
more bytes before stopping.
When operating in polled mode, this is
indicated using the PTPA and STPA
inputs.
When operating in direct status mode,
this is indicated using the DTPA inputs.
Link
Receive
(Sink) The interface indicates, by
asserting low the RENB output,
that it is not full when it has more
than or equal to FIFO buffer
threshold spaces for bytes in all of
its FIFO buffers (1 FIFO buffer per
channel). The interface indicates,
by deasserting high the RENB
output, that it is full when it has no
more spaces for bytes in any of its
FIFO buffers (1 FIFO buffer per
channel). This should be set to the
minimum value allowed. —