Altera Low Latency 40-Gbps Ethernet MAC and PHY MegaCore Function User Manual
Page 132
Addr
Name
Bit
Description
HW Reset
Value
Access
0x606
TX_PAUSE_
REQUEST
[N-
1:0]
(9)
Pause request. If bit [n] of the
TX_PAUSE_EN
register has the value of 1, setting bit [n] of
the
TX_PAUSE_REQUEST
register field to the
value of 1 triggers a XOFF pause packet
insertion into the TX data stream on the
Ethernet link. If the IP core implements
priority-based flow control, the XOFF pause
packet includes identity information for the
corresponding priority queue.
If
RETRANSMIT_XOFF_HOLDOFF_EN
is turned
on for the associated priority queue, as long
as the value in
TX_PAUSE_REQUEST
bit [n]
remains high, the IP core retransmits the
XOFF pause packet at intervals determined
by the retransmit hold-off value associated
with this priority queue.
If bit [n] of the
TX_PAUSE_EN
register has the
value of 1, resetting bit [n] of the
TX_PAUSE_
REQUEST
register field to the value of 0
triggers an XON pause packet insertion into
the TX data stream on the Ethernet link. If
the IP core implements priority-based flow
control, the XON pause packet includes
identity information for the corresponding
priority queue.
Other pause registers, described in this table,
specify the properties of the pause packets.
Altera recommends that you signal a pause
request using the
pause_insert_tx
signal
rather than using the
TX_PAUSE_REQUEST
register.
0
RW
0x607
RETRANSMIT_
XOFF_
HOLDOFF_EN
[N-
1:0]
(9)
Enable XOFF pause frame retransmission
hold-off functionality. If your IP core
implements priority-based flow control with
multiple priority queues, this register
provides access to one bit for each priority
queue.
Altera recommends that you maintain this
register at the value of all ones.
If your IP core implements priority-based
flow control, refer also to the description of
the
CFG_RETRANSMIT_HOLDOFF_EN
and
CFG_
RETRANSMIT_HOLDOFF_QUANTA
registers.
N'b1...1 (1'b1
in each
defined bit)
RW
UG-01172
2015.05.04
Pause Registers
3-87
Functional Description
Altera Corporation