Miscellaneous signals, Smbus interface signals – Intel 41210 User Manual

Page 62

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62

Intel® 41210 Serial to Parallel PCI Bridge Design Guide

Design Guide Checklist

Table 21. Miscellaneous Signals

Signals

Recommendations

Reason/Impact

RSTIN#

Used for debug purposes. Connect to VCC33 through
an 8.2K

pullup resistor for normal operation.

A_STRAP0,
A_STRAP1,
A_STRAP2,
A_STRAP6,

B_STRAP0,
B_STRAP1,
B_STRAP2,
B_STRAP6

RESERVED [8:1]

These signals REQUIRE external pull-downs to GND
on the board 8.2K

unless otherwise stated.

CFGRETRY

Input pin to configure 41210 to retry configuration
accesses on it's PCI Express interface.

To retry configuration accesses to the 41210, pull high to

3.3V through a 2K

resistor.

To allow configuration accesses to the 41210, ground this
pin through a 2K

resistor.

A_TEST1,
A_TEST2,
B_TEST1,
B_TEST2

A_PME#,
B_PME#,
A_STRAP[3],
A_STRAP[4],
A_STRAP[5],
B_STRAP[3],
B_STRAP[4],
B_STRAP[5]

These signals REQUIRE an external pull-up, 8.2K

to

3.3V.

NC17

This signal requires an external pull-up, 8.2K

to 3.3V.

In normal operating mode, this
pin must be tied high.

Table 22. SMBus Interface Signals

Signal

Recommendations

Reason/Impact

SMBCLK

Connect to VCC33 through an 8.2K

pullup resistor.

SMBDAT

Connect to VCC33 through an 8.2K

pullup resistor.

SMBUS[5],
SMBUS[3:1]

SMBus addressing:

Bit 7----------------’1’

Bit 6----------------’1’

Bit 5---------------SMBUS[5]

Bit 4----------------’0’

Bit 3---------------SMBUS[3]

Bit 2---------------SMBUS[2]

Bit 1---------------SMBUS[1]

Use 8.2K

resistors as pullups to VCC33 for a ‘1’ and

as pulldowns to ground for a ‘0’ to set the SMBus
address.

Sampled on the rising edge of
PERST#.

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