Altera Triple Speed Ethernet MegaCore Function - Manual (Page 123)

Description I/O Avalon-ST Signal
Type
Name
Asserted when an underflow occurs on the
transmit FIFO buffer. O —
tx_ff_uflow
Deasserted when the FIFO buffer is filled to or
above the section-empty threshold defined in the
tx_section_empty
register. User applications
can use this signal to indicate when to stop
writing to the FIFO buffer and initiate backpres-
sure.
O —
ff_tx_septy
Asserted when the transmit FIFO buffer reaches
the almost- full threshold. O —
ff_tx_a_full
Asserted when the transmit FIFO buffer goes
below the almost-empty threshold. O —
ff_tx_a_empty
Pause and Magic Packet Signals
The pause and magic packet signals are component-specific signals.
Table 7-9: Pause and Magic Packet Signals
Description I/O Name
Assert this signal for at least 1 tx_clk clock cycle to trigger the
generation of a pause frame with a 0 pause quanta. The MAC function
generates the pause frame independent of the status of the receive
FIFO buffer.
This signal is not in use in the following conditions:
• Ignored when the
xon_gen
bit in the
command_config
register is
set to 1.
• Absent when the Enable full duplex flow control option is turned
off.
I xon_gen
Assert this signal for at least one
tx_clk
clock cycle to trigger the
generation of a pause frame with a pause quanta configured in the
pause_quant
register. The MAC function generates the pause frame
independent of the status of the receive FIFO buffer.
This signal is not in use in the following conditions:
• Ignored if the
xoff_gen
bit in the
command_config
register is set
to 1.
• Absent when the Enable full duplex flow control option is turned
off.
I
xoff_gen
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Pause and Magic Packet Signals 7-8
2014.06.30