Altera PCI Compiler - Manual (Page 259)

Altera Corporation User Guide Version 11.1 6–9
October 2011
Parameter Settings
System
Options-2 The System Options - 2 tab in the PCI Compiler wizard defines the
complexity of the PCI-to-Avalon bridge. On this tab, you specify the
following PCI bus configurations:
■ PCI Bus Speed
■ PCI Global Reset Signal
■ PCI Data Bus Width
■ Clock Domains
■ PCI Bus Arbiter
PCI Bus Speed
PCI Bus Speed selections determine the system’s maximum clock rate.
If you select the 66-MHz clock rate, the capable bit
(pci_66mhz_capable)—which is bit 5 of the PCI status register—is set
to 1. Refer to
Table 3–17 on page 3–33 .
PCI Data Bus Width
PCI Data Bus Width selections determine the system’s PCI bus width.
Additionally, the PCI-Avalon bridge automatically configures the
Avalon-MM data width to be the same as the PCI data bus width.
Therefore, selecting a 64-bit PCI data bus instantiates either the
pci_mt64
or pci_t64 MegaCore function, depending on the PCI
Device Mode you specified in the System Options – 1 tab. Likewise,
selecting a 32-bit PCI data bus instantiates either the pci_mt32 or
pci_t32
MegaCore function, depending on the PCI Device Mode you
specified in the System Options – 1 tab.
PCI Clock/Reset Settings
Turning on the Enable Independent Avalon System Reset enables a
second reset signal named reset_n in the SOPC system. When
triggered, this signal resets the entire SOPC system except the PCI
Compiler, thus preserving its configuration.
The Independent PCI and Avalon Clocks option allows the PCI bus and
Avalon-MM interface to use independent clocks that can run at the same
or different speeds. Choosing this option provides maximum flexibility
but also requires more logic resources and adds latency. When you select
this option, the SOPC Builder generates a system with two clock pins
driving the PCI-Avalon bridge. One clock pin has the PCI-Avalon
bridge’s instance name and should be connected to the PCI clock source.
The other clock pin has the PCI-Avalon bridge’s instance name
appended to it and should be connected to the system’s clock source.