The priority flow control (PFC) interface is used to initiate the transmission of PFC frames from the core. The ports associated with this interface are shown in the following table. This interface is only present when priority-based flow control is enabled in the MAC features tab of the GUI. When the optional PFC is enabled, there are eight AXI4-Stream interfaces defined for each Class of Service.
| Signal Name | Direction | Description |
|---|---|---|
| s_axis_tx_pfc0_tvalid | In | Pause request from priority 0 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc1_tvalid | In | Pause request from priority 1 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc2_tvalid | In | Pause request from priority 2 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc3_tvalid | In | Pause request from priority 3 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc4_tvalid | In | Pause request from priority 4 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc5_tvalid | In | Pause request from priority 5 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc6_tvalid | In | Pause request from priority 6 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| s_axis_tx_pfc7_tvalid | In | Pause request from priority 7 FIFO in the TEMAC. This results in a PFC frame at the next available point. |
| m_axis_rx_pfc0_tready | In | Pause acknowledge from priority 0 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc0_tvalid | Out | Pause request to priority 0 RX FIFO in the TEMAC. |
| m_axis_rx_pfc1_tready | In | Pause acknowledge from priority 1 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc1_tvalid | Out | Pause request to priority 1 RX FIFO in the TEMAC. |
| m_axis_rx_pfc2_tready | In | Pause acknowledge from priority 2 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc2_tvalid | Out | Pause request to priority 2 RX FIFO in the TEMAC. |
| m_axis_rx_pfc3_tready | In | Pause acknowledge from priority 3 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc3_tvalid | Out | Pause request to priority 3 RX FIFO in the TEMAC. |
| m_axis_rx_pfc4_tready | In | Pause acknowledge from priority 4 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc4_tvalid | Out | Pause request to priority 4 RX FIFO in the TEMAC. |
| m_axis_rx_pfc5_tready | In | Pause acknowledge from priority 5 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc5_tvalid | Out | Pause request to priority 5 RX FIFO in the TEMAC. |
| m_axis_rx_pfc6_tready | In | Pause acknowledge from priority 6 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc6_tvalid | Out | Pause request to priority 6 RX FIFO in the TEMAC. |
| m_axis_rx_pfc7_tready | In | Pause acknowledge from priority 7 RX FIFO in the TEMAC. The captured quanta only start to expire when this is asserted. If unused this should be tied High. |
| m_axis_rx_pfc7_tvalid | Out | Pause request to priority 7 RX FIFO in the TEMAC. |