Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
3.0
Functional Signal Descriptions
Listed in the signal definition tables — starting at Table 6 “SDRAM Interface” on page 34 — are
pull-up an pull-down resistor recommendations that are required when the particular enabled
interface is not being used in the application. These external resistor requirements are only needed
if the particular model of Intel® IXP42X product line and IXC1100 control plane processors has
the particular interface enabled and the interface is not required in the application.
Warning:
All IXP42X product line and IXC1100 control plane processors I/O pins are not 5-V tolerant.
Disabled features, within the IXP42X product line and IXC1100 control plane processors, do not
require external resistors as the processor will have internal pull-up or pull-down resistors enabled
as part of the disabled interface.
Table 5 presents the legend for interpreting the Type field in the other tables in this section of the
document.
To determine which interfaces are not enabled within the IXP42X product line and IXC1100
control plane processors, see Table 3 on page 14.
Table 5.
Signal Type Definitions
Symbol
Description
I
O
Input pin only
Output pin only
I/O
OD
PWR
GND
1
Pin can be either an input or output
Open Drain pin
Power pin
Ground pin
Driven to Vcc
0
Driven to Vss
X
Driven to unknown state
Input is disabled
ID
H
Pulled up to Vcc
L
Pulled to Vss
PD
Z
Pull-up Disabled
Output Disabled
VO
VI
A valid output level is driven, allowed states -- 1, 0, H, Z
Need to drive a valid input level, allowed states - 1, 0, H, Z
Pull-up Enabled, equivalent to H
Output Only/Tristatable
No Connect
PE
Tri
N/C
-
Pin must be connected as described
Other tables in this section include:
• Table 6 — SDRAM Interface signals
• Table 7 — PCI Controller signals
Datasheet
March 2005
33
Document Number: 252479, Revision: 005
INTEL [ INTEL ]
