Filter
Top Products
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
February 2007 HDD
Document Number: 305261; Revision: 004 49
General Hardware Design Considerations—Intel
®
IXP45X and Intel
®
IXP46X Product Line of
Network Processors
3.12.2 PCI Interface Block Diagram
When using the IXP45X/IXP46X network processors in Master mode, the PCI module
can interface to up to four PCI cards (devices) at 33 MHz or two PCI cards at 66 MHz.
The limitation to two cards (devices) at 66 MHz is due to load requirements to maintain
signal integrity at the higher frequency.
The PCI-to-PCI bridge must be used in order to address the PCI requirement not to
exceed one load per PCI connector unless it is through a PCI-to-PCI bridge.
The IDSEL signals on the PCI slots can be connected to one of the PCI_AD lines,
preferable to the higher order address signals. Reset support can be accomplished by
using one of the GPIO pins to generate a reset or through an external decoder of the
Expansion bus.
PCI_IDSEL I Yes
Initialization Device Select.
When this interface/signal is enabled and is not being used in a system design, the interface/
signal should be pulled high with a 10-KΩ resistor.
PCI_REQ_N[3:1] I Yes
Arbitration Request.
When this interface/signal is enabled and is not being used in a system design, the interface/
signal should be pulled high with a 10-KΩ resistor.
PCI_REQ_N[0] I/O Yes
Arbitration Request:
When this interface/signal is enabled and is not being used in a system design, the interface/
signal should be pulled high with a 10-KΩ resistor.
PCI_GNT_N[3:1] O No Arbitration Grant.
PCI_GNT_N[0] I/O Yes
Arbitration Grant.
When this interface/signal is enabled and is not being used in a system design, the interface/
signal should be pulled high with a 10-KΩ resistor.
PCI_INTA_N O/D Yes
Interrupt A.
When this interface/signal is enabled and is either used or not used in a system design, the
interface/signal should be pulled high with a 10-KΩ resistor.
PCI_CLKIN I Yes
Clock input.
When this interface/signal is enabled and is not being used in a system design, the interface/
signal should be pulled high with a 10-KΩ resistor.
Table 20. PCI Controller (Sheet 2 of 2)
Name
Input/
Outpu
t
Pull
Up/
Down
Recommendations
Notes:
1. Features disabled/enabled by Soft Fuse must be done during the boot-up sequence. A feature cannot be enabled after
being disabled without asserting a system reset.
2. Features disabled by a specific part number, do not require pull-ups or pull-downs. Therefore, all pins can be left
unconnected.
3. Features enabled by a specific part number — and required to be Soft Fuse-disabled, as stated in Note 1 — only require
pull-ups or pull-downs in the clock-input signals.