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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—General Hardware
Design Considerations
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
HDD February 2007
50 Document Number: 305261; Revision: 004
3.12.3 Supporting 5 V PCI Interface
It is possible to support 5 V PCI devices with the help of voltage logic translators. One
option can be implemented with voltage level translator. The Texas Instruments* family
of FET bus switches CBT devices can be a good solution. The 10-bit SN74CBT3384A has
been proven to work very effectively with the Intel
®
IXP465 Network Processor. All
control and DATA/ADDRESS signals (bidirectional and not) need to be translated before
connecting the 3.3 V to the 5 V logic together. Signals which are not used, do not need
to be translated, simply follow the recommendations described in Table 20.
Figure 17 shows a block diagram of the interface required to perform the conversion.
Ensure that all signals connect to either of the two interfacing logic levels.
T
PROP
(Bus Propagation Delay) is the maximum time for a complete flight. When you
calculate T
PROP,
you must include in your timing calculation the T
PD
(Time for
Propagation Delay) of the voltage translator. For details, refer to Section 6.2.
Figure 16. PCI Interface
Intel
®
IXP46X
Product Line
Network Processor
Transparent P CI
Bridge
cPCI J2
Compact PCI Bus
PCI Bus
cPCI J1
PCI Slots
PCI Interface
B4110-001