Revision 1.02 – April 12, 2007
S5920 – PCI Product: Pass-Thru Operation
Data Book
(disconnect, but with no data transfer), the read data is
held in the FIFO until the master comes back for it. In
this case, the Retry Flush Enb has no effect. The PCI
2.1 Specification states that the master must come
back if it receives a retry.
tiator will have to come back to complete the data
transfer, after which time the FIFO should no longer be
full. If Write FIFO Mode is high, the S5920 will deas-
sert TRDY#, and allow for either another FIFO location
to become available (as the Add-On has read a
DWORD), or wait for the Target Latency to expire (8
clocks from previous data phase), thus initiating a dis-
connect. This will allow for the Add-on device to
“catch-up” without losing the burst.
Write FIFO Mode indicates what to do in the event that
a full FIFO is detected during a PCI write transfer. If
low, the S5920 will perform an immediate disconnect,
thus freeing up the PCI bus for other transfers. The ini-
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