For the AXI Ethernet Subsystem, a pause frame transmission can be initiated by writing a pause value to the Transmit Pause Frame Register while transmit pause processing is enabled (FCC register bit 30 in 1; see the Tri-Mode Ethernet MAC LogiCORE IP Product Guide (PG051).
Requesting a pause frame transmission does not interrupt a transmission in progress; the pause frame is transmitted after the frame in progress. A request to transmit a pause frame results in the transmission of a pause frame even if the transmitter itself is already paused due to the reception of a pause frame.
The destination address supplied with the transmitted pause control frame can be set by writing to the RCW0 and RCW1 registers (Table 1).