Altera PCI Compiler - Manual (Page 64)

2–6 User Guide Version 11.1 Altera Corporation
PCI Compiler October 2011
Advanced PCI MegaCore Function Features
Disable Master Latency Timer
Turning on the Disable Master Latency Timer option allows you to
disable the latency timer time-out feature. If the latency timer time-out is
disabled, the master will continue the burst transaction even if the latency
timer has expired and the gntn signal is removed. This feature is useful
in systems in which breaking up long data transfers in small transactions
will yield undesirable side effects.
1 Disabling the Disable Master Latency Timer violates the PCI
specification and therefore should only be used in embedded
applications where the designer can control the entire system
configuration. Disabling the master latency timer can also result
in increased latency for other master devices in the system. If
increased latency for other master devices is unacceptable in
your application, this option should not be used.
Assume ack64n Response
This feature provides enhanced master functionality when using the
pci_mt64
MegaCore function in systems where a 64-bit transaction
request is always accepted by a 64-bit target asserting ack64n. This
feature can be used where the bit width of all devices is known, such as
in an embedded system, and where all 64-bit targets respond with
ack64n
asserted.
With this option turned on, the pci_mt64 master supports 64-bit single-
cycle write transactions and asserts irdyn one clock cycle after framen
is asserted. For more information, refer to
“64-Bit Single Cycle Memory
Write Master Transactions” on page 3–121 .