6.7. Avalon® Streaming Flow Control Signals
This signal takes effect when the register bits, tx_pauseframe_enable[2:1], are both set to the default value 0.
Set this signal to the following values to trigger the corresponding actions.
|avalon_st_tx_pause_length_valid||All||In||1||This signal is present in the MAC TX only variation.
Assert this signal to request the MAC IP core to suspend data transmission. When you assert this signal, ensure that a valid pause quanta is available on the avalon_st_tx_pause_length_data bus.
|avalon_st_tx_pause_length_data||All||In||16||This signal is present in the MAC TX only variation.
Use this bus to specify the pause quanta in unit of quanta, where 1 unit = 512 bits time.
| n = 2 x Number of PFC queues parameter.
Each pair of bits is associated with a priority queue. Bits 0 and 1 are for priority queue 0, bits 2 and 3 are for priority queue 1, and so forth. Set the respective pair of bits to the following values to trigger the specified actions for the corresponding priority queue.
| n = Number of PFC queues parameter.
When the MAC RX receives a pause frame, it asserts bit n of this signal when the pause quanta for the n th queue is valid (Pause Quanta Enable [n] = 1) and greater than 0. For each quanta unit, the MAC RX asserts bit n for eight clock cycle.
The MAC RX deasserts bit n of this signal when the pause quanta for the n th queue is valid (Pause Quanta Enable [n] = 1) and equal to 0. The MAC RX also deasserts bit n when the timer expires.
|avalon_st_rx_pause_length_valid||All||Out||1||This signal is present in the MAC RX only variation.
The MAC IP core asserts this signal to request its link partner to suspend data transmission. When asserted, a valid pause quanta is available on the avalon_st_rx_pause_length_data bus.
|avalon_st_rx_pause_length_data||All||Out||16||This signal is present only in the MAC RX only variation.
Specifies the pause quanta in unit of quanta, where 1 unit = 512 bits time.