OPERATION
Copyright 2012
4-5
FibreXtreme HW Reference for FPDP Cards
4.4.5 Stop on Link Error or /SYNC
There are two DMA stop conditions available to the user—stop on link error and stop on
/SYNC. The stop on link error stops the DMA engine from removing data from the
Receive FIFO when there is a link error, such as the link going down. The stop on
/SYNC option allows you to stop data from being received from the Receive FIFO when
a /SYNC without /DVALID is received on the output.
4.4.6 Receive FIFO Threshold Interrupt
SL240 cards can be configured to interrupt the host when the FIFO passes a certain
threshold, allowing for efficient PIO transactions out of the Receive FIFO. This is
particularly important on data storage systems, where you do not want to remove data
from the FIFO until you have a full block of data to transmit. One of four different
thresholds (not empty, ¼ full, ½ full, ¾ full) can be selected through the control
registers.
