Altera 10-Gbps Ethernet MAC MegaCore Function - Manual (Page 137)

9–18 Chapter 9: Interface Signals
10-Gbps Ethernet MAC MegaCore Function User Guide February 2014 Altera Corporation
Table 9–9 describes the Avalon-ST flow control signals.
Table 9–9. Avalon-ST Flow Control Signals (Part 1 of 3)
Signal Direction Width Description
avalon_st_pause_data[] Input 2
Assert this signal to generate pause frames:
■ Bit 0: Set to 1 to generate an XON pause frame.
■ Bit 1: Set to 1 to generate an XOFF pause frame.
You can also use the tx_pauseframe_control
register to generate pause frames. The register takes
precedence over this signal.
avalon_st_rx_pfc_pause_data[] (1) Output 2-8
The signal width is determined by the Number of PFC
priorities parameter, n = number priority queues
enabled.
The MAC RX asserts bit n when the Pause Quanta n
field in the PFC frame is valid (Pause Quanta Enable [n]
= 1) and greater than 0. For each pause quanta unit, the
MAC RX asserts bit n for eight clock cycle.
The MAC RX deasserts bit n when the Pause Quanta n
field in the PFC frame is valid (Pause Quanta Enable [n]
= 1) and equal to 0. The MAC RX also deasserts this
signal when the timer expires.