Figure 19: fifo sections configuration and signals, Figure 20: fifo sections related signaling – Achronix Speedster22i 10G/40G/100G Ethernet User Manual
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UG029, September 6, 2013
The following figure shows the relationship of the configuration values and their respective
signals and levels above and below the levels.
Figure 19: FIFO Sections Configuration and Signals
Figure 20: FIFO Sections Related Signaling
The two signals RX FIFO septy and TX FIFO sav are used internally by the MAC to generate
pause frames and start transmission of frames to the line, respectively.
The other two signals (TX FIFO septy and RX FIFO dsav) are maintained for legacy reasons
only. Note: These signals are not available in this implementation.
rx/tx_section
rx/tx_section_e
dsav
septy
1
0
0
1
RX FIFO
TX FIFO
MAC
TX
RX
ff_rx_dsav
ff_tx_septy
septy
sav
FIFO nearly full
FIFO has at least
one section of data
start transmission
send PAUSE
full indication
FIFO empty
(implicit by dval)
FIFO is full
ff_tx_rdy