Intel® 41210 Serial to Parallel PCI
Bridge
Design Guide
May 2005
Order Number: 278801-004
Download from Www.Somanuals.com. All Manuals Search And Download.
Contents
Contents
About This Document ...................................................................................................................7
1.1 Terminology and Definitions .................................................................................................7
Introduction....................................................................................................................................9
PCI Express Interface Features............................................................................................9
PCI-X Interface Features......................................................................................................9
SMBus Interface .................................................................................................................10
2.4.1 SMBus for configuration register initialization........................................................10
2.4.2 Microcontroller Connections to the 41210 Bridge..................................................11
JTAG...................................................................................................................................12
Intel®41210 Serial to Parallel PCI Bridge Applications......................................................13
Package Information ...................................................................................................................15
3.1 Package Specification ........................................................................................................15
Power Plane Layout ....................................................................................................................19
41210 Bridge Decoupling Guidelines .................................................................................19
41210 Bridge Reset and Power Timing Considerations ..........................................................23
A_RST#,B_RST# and PERST# Timing Requirements ......................................................23
VCC15 and VCC33 Voltage Requirements........................................................................23
General Routing Guidelines .......................................................................................................25
General Routing Guidelines................................................................................................25
Crosstalk.............................................................................................................................25
Power Distribution and Decoupling.....................................................................................27
6.4.1 Decoupling.............................................................................................................27
Trace Impedance................................................................................................................27
6.5.1 Differential Impedance...........................................................................................28
Board Layout Guidelines............................................................................................................29
7.1 Adapter Card Topology.......................................................................................................29
PCI-X Layout Guidelines.............................................................................................................31
Interrupts.............................................................................................................................31
8.1.1 Interrupt Routing for Devices Behind a Bridge.......................................................32
PCI Arbitration ....................................................................................................................32
8.2.1 PCI Resistor Compensation ..................................................................................33
PCI General Layout Guidelines ..........................................................................................33
8.3.1 PCI Pullup Resistors Not Required........................................................................34
PCI Clock Layout Guidelines..............................................................................................35
PCI-X Topology Layout Guidelines.....................................................................................38
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
iii
Download from Www.Somanuals.com. All Manuals Search And Download.
Contents
8.6.1 Embedded PCI-X 133 MHz ...................................................................................39
8.6.2 Embedded PCI-X 100 MHz ...................................................................................40
8.6.3 PCI-X 66 MHz Embedded Topology......................................................................41
8.6.4 PCI 66 MHz Embedded Topology .........................................................................42
8.6.5 PCI 33 MHz Embedded Mode Topology ...............................................................43
PCI Express Layout.....................................................................................................................45
General recommendations .................................................................................................45
PCI-Express Layout Guidelines..........................................................................................46
Adapter Card Layout Guidelines.........................................................................................46
Circuit Implementations..............................................................................................................49
10.1 41210 Bridge Analog Voltage Filters ..................................................................................49
10.1.1 PCI Analog Voltage Filters.....................................................................................50
10.1.2 PCI Express Analog Voltage Filter ........................................................................50
10.1.3 Bandgap Analog Voltage Filter..............................................................................51
10.2.1 SM Bus ..................................................................................................................54
41210 Bridge Customer Reference Boards...............................................................................55
11.1 Board Stack-up...................................................................................................................55
11.2 Material...............................................................................................................................56
11.3 Impedance..........................................................................................................................56
11.4 Board Outline......................................................................................................................57
Design Guide Checklist ..............................................................................................................59
Figures
41210 Bridge Microcontroller Block Diagram .............................................................................11
41210 Bridge Microcontroller Connections.................................................................................11
41210 Bridge Block Diagram......................................................................................................12
Intel® 41210 Bridge Adapter Card Block Diagram......................................................................13
Top View - 41210 Bridge 567-Ball FCBGA Package Dimensions..............................................15
Bottom View - 41210 Bridge 567-Ball FCBGA Package Dimensions ........................................16
Side View - 41210 Bridge 567-Ball FCBGA Package Dimensions.............................................17
Decoupling Placement for Core and PCI Express Voltage Planes ............................................19
Decoupling Placement for PCI/PCI-X 1.5V and 3.3V Voltage Planes........................................20
10 41210 Bridge Single-Layer Split Voltage Plane..........................................................................22
11 Crosstalk Effects on Trace Distance and Height ........................................................................26
12 PCB Ground Layout Around Connectors ...................................................................................26
13 Cross Section of Differential Trace.............................................................................................28
14 Two-by-two Differential Impedance Matrix .................................................................................28
15 Adapter Card Stackup ................................................................................................................30
16 PCI RCOMP ...............................................................................................................................33
17 PCI Clock Distribution and Matching Requirements...................................................................36
18 Embedded PCI-X 133 MHz Topology ........................................................................................39
19 Embedded PCI-X 100 MHz Topology ........................................................................................40
20 PCI-X 66 MHz Embedded Routing Topology.............................................................................41
21 PCI 66 MHz Embedded Topology..............................................................................................42
iv
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Contents
22 PCI 33 MHz Embedded Mode Routing Topology.......................................................................43
23 PCI Analog Voltage Filter Circuit ................................................................................................50
24 PCI Express Analog Voltage Filter Circuit ..................................................................................51
25 Bandgap Analog Voltage Filter Circuit........................................................................................52
26 Reference and Compensation Circuit Implementations .............................................................53
27 Proposed Mechanical Outline of the 41210 Bridge ....................................................................57
Tables
Terminology and Definitions .........................................................................................................7
Adapter Card Stack Up, Microstrip and Stripline ........................................................................29
INTx Routing Table.....................................................................................................................31
Interrupt Binding for Devices Behind a Bridge...........................................................................32
PCI-X Signals .............................................................................................................................34
PCI/PCI-X Frequency/Mode Straps............................................................................................34
PCI-X Clock Layout Requirements Summary.............................................................................37
PCI-X Slot Guidelines.................................................................................................................38
10 Embedded PCI-X 133 MHz Routing Recommendations............................................................39
11 Embedded PCI-X 100 MHz Routing Recommendations............................................................40
12 PCI-X 66 MHz Embedded Routing Recommendations..............................................................41
13 PCI 66 MHz Embedded Table....................................................................................................42
14 PCI 33 MHz Embedded Routing Recommendations..................................................................43
15 Adapter Card Routing Recommendations..................................................................................46
16 Recommended R, L and C Values for 41210 Bridge Analog Filter Circuits ...............................49
17 SMBUs Address Configuration...................................................................................................54
18 CRB Board Stackup....................................................................................................................56
19 PCI Express Interface Signals....................................................................................................59
20 PCI/PCI-X Interface Signals .......................................................................................................60
21 Miscellaneous Signals ................................................................................................................62
22 SMBus Interface Signals ............................................................................................................62
23 Power and Ground Signals.........................................................................................................63
24 JTAG Signals..............................................................................................................................64
Revision History
Date
Revision
Description
Removed Section 5.3, VCCPE and REFCLKn/REFCLKp
Information
May 2005
004
Added signals to Section 8.3.1
Updated Table 19, Table 20, and Table 21
Updated PCI Express operation information in Section 2.1 and
Table 19.
October 2004
003
Added signal NC17 information in Table 21.
Updated Chapters 4, 5, and 12
July 2004
October 2003
July 2003
002
001
000
Updated content; second draft of this document; initial public
release of this document.
First internal draft of this document.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
v
Download from Www.Somanuals.com. All Manuals Search And Download.
Contents
This page intentionally left blank.
vi
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
About This Document
1
This document provides layout information and guidelines for designing platform or add-in board
applications with the Intel® 41210 Serial to Parallel PCI Bridge (also called the 41210 Bridge). It is
recommended that this document be used as a guideline. Intel recommends employing best-known
design practices with board level simulation, signal integrity testing and validation for a robust
design.
Designers should note that this guide focuses upon specific design considerations for the 41210
Bridge and is not intended to be an all-inclusive list of all good design practices. Use this guide as
a starting point and use empirical data to optimize your particular design.
1.1
Terminology and Definitions
Table 1 provides a list of terms and definitions that may be useful when working with the 41210
Bridge product.
Table 1. Terminology and Definitions (Sheet 1 of 2)
Term
Definition
Stripline in a PCB is composed of the
conductor inserted in a dielectric with GND
planes to the top and bottom.
Stripline
NOTE: An easy way to distinguish stripline
from microstrip is that you need to
strip away layers of the board to view
the trace on stripline.
Microstrip in a PCB is composed of the
conductor on the top layer above the dielectric
with a ground plane below
Microstrip
Material used for the lamination process of manufacturing PCBs. It consists of a layer of
epoxy material that is placed between two cores. This layer melts into epoxy when heated and
forms around adjacent traces.
Prepreg
Core
Material used for the lamination process of manufacturing PCBs. This material is two sided
laminate with copper on each side. The core is an internal layer that is etched.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
7
Download from Www.Somanuals.com. All Manuals Search And Download.
About This Document
Table 1. Terminology and Definitions (Sheet 2 of 2)
Term
Definition
Printed circuit board.
Layer 1: copper
Prepreg
Example manufacturing process consists of
the following steps:
Layer 2: GND
•
Consists of alternating layers of core and
prepreg stacked
Core
•
•
•
•
•
The finished PCB is heated and cured.
The via holes are drilled
PCB
Layer 3: VCC15
Prepreg
Layer 4: copper
Plating covers holes and outer surfaces
Etching removes unwanted copper
Board is tinned, coated with solder mask
and silk screened
Example of a Four-Layer Stack
SSTL_2
JEDEC
Series Stub Terminated Logic for 2.5 V
Provides standards for the semiconductor industry.
A network that transmits a coupled signal to another network is aggressor network.
Zo
Zo
Aggressor
Zo
Zo
Victim Network
Aggressor Network
Victim
Network
Stub
A network that receives a coupled cross-talk signal from another network is a victim network.
The trace of a PCB that completes an electrical connection between two or more components.
Branch from a trunk terminating at the pad of an agent.
CRB
Customer Reference Board
Downstream refers either to the relative position of an interconnect/system element (Link/
Downstream device) as something that is farther from the Root Complex, or to a direction of information
flow, i.e., when information is flowing away from the Root Complex.
Upstream
®
Memory subsystem on the Intel XScale core DDR SDRAM or Peripheral Bus Interface
Local memory
busses.
DWORD
32-bit data word.
FC-BGA (flip chip-ball grid array) chip packages are designed with processor core flipped up
on the back of the chip, facing away from the PCB. This allows more efficient cooling of the
package.
Flip Chip
Mode
Conversion
Mode Conversions are due to imperfections on the interconnect which transform differential
mode voltage to common mode voltage and common mode voltage to differential voltage.
PCI-E
PCI-Express
8
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
2
The Intel®41210 Serial to Parallel PCI Bridge integrates two PCI Express-to-PCI bridges. Each
bridge follows the PCI-to-PCI Bridge programming model. The PCI Express port is compliant to
the PCI Express Specification, Revision 1.0. The two PCI bus interfaces are fully compliant to the
PCI Local Bus Specification, Revision 2.3.
2.1
PCI Express Interface Features
• PCI Express Specification, Revision 1.0b compliant.
• Support for single x8, single x4 or single x1 PCI Express operation.
• 64-bit addressing support.
• 32-bit CRC (cyclic redundancy checking) covering all transmitted data packets.
• 16-bit CRC on all link message information.
• Raw bit-rate on the data pins of 2.5 Gbit/s, resulting in a raw bandwidth per pin of 250 MB/s.
• Maximum realized bandwidth on PCI Express interface is 2 GB/s (in x8 mode) in each
direction simultaneously, for an aggregate of 4 GB/s.
2.2
PCI-X Interface Features
• PCI Local Bus Specification, Revision 2.3 compliant.
• PCI-to-PCI Bridge Specification, Revision 1.1 compliant.
• PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0a compliant.
• 64-bit 66 MHz, 3.3 V, NOT 5 V tolerant.
• On Die Termination (ODT) with 8.2KΩ pull-up to 3.3V for PCI signals.
• Six external REQ/GNT Pairs for internal arbiter on segment A and B respectively.
• Programmable bus parking on either the last agent or always on Lanai.
• 2-level programmable round-robin internal arbiter with Multi-Transaction Timer (MTT)
• External PCI clock-feed support for asynchronous primary and secondary domain operation.
• 64-bit addressing for upstream and downstream transactions
• Downstream LOCK# support.
• No upstream LOCK# support.
• PCI fast Back-to-Back capable as target.
• Up to four active and four pending upstream memory read transactions
• Up to two downstream delayed (memory read, I/O read/write and configuration read/write)
transaction.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
9
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
• Tunable inbound read prefetch algorithm for PCI MRM/MRL commands
• Local initialization via SMBus
• Secondary side initialization via Type 0 configuration cycles.
2.3
Power Management
• Support for PCI Express Active State Power Management (ASPM) L0s link state
• Support for PCI PM 1.1 compatible D0, D3hot and D3cold device power states
• Support for PME# event propagation on behalf of PCI devices
2.4
SMBus Interface
• Compatible with System Management Bus Specification, Revision 2.0
• Slave mode operation only.
• Full read/write access to all configuration registers
2.4.1
SMBus for configuration register initialization
• Support for local initialization of the configuration registers can be implemented using a
the 41210 Bridge and the microcontroller.
• Configuration Register information is stored internally in a microcontroller and the
information is transferred to the product via System Managed Bus (SMBus) protocols when
the device receives power or reset.
• The requirements of the microcontroller are as follows:
— Supports I2C and SMBus Protocols
— Has at least 256 Byte of internal EEprom space
— To facilitate this programming on the Customer Reference Board a Microchip part
PIC16F876A was used.
— Code space: estimated code size is ~2K words of program space and 32 words of RAM
10
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
Figure 1. 41210 Bridge Microcontroller Block Diagram
SMBus 2.0
Microcontroller
Intelfi 41210 Bridge
Configuration
Register
Data
Configuration
Register
Address Space
B2707-01
2.4.2
Microcontroller Connections to the 41210 Bridge
The following diagram shows the SMB interface from the 41210 Bridge to the microcontroller.
Figure 2. 41210 Bridge Microcontroller Connections
3.3 V
PIC16F876A
Intelfi 41210
SMDAT
Bridge
SMBDAT
SDI / SDA
SCK / SCL
SMCLK
SMBCLK
OSC2 / CLKOUT
CFG_RETRY
CFGRETRY
RC1
20 MHz
CFG_RESET
CFG_RST_N
RBO / INT
OSC1 / CLKIN
22 pF
22 pF
B2708-01
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
11
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
2.5
JTAG
• Compliant with IEEE Standard Test Access Port and Boundary Scan Architecture 1149.1a
2.6
Related Documents
• Intel® 41210 Serial to Parallel PCI Bridge Design Specification (EDS), Revision 1.0.
• PCI Express Design Guide, Revision 0.5
• IEEE Standard Test Access Port and Boundary Scan Architecture 1149.1a
• System Management Bus Specification, Revision 2.0
Figure 3. 41210 Bridge Block Diagram
JTAG
SMB Bus
A Bus PCI-X 133MHz
fi
Intel
PCI-Express x8
6 REQ/GNT Pairs
6 A_PCLKO
A
41210 Bridge
Bus Arbiter
A
Clock Buffer
B Bus PCI-X 133MHz
6 REQ/GNT Pairs
6 B_PCLKO
B
Bus Arbiter
B
Clock Buffer
A_PCLKI
B_PCLKI
B2709-01
12
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
2.7
Intel®41210 Serial to Parallel PCI Bridge
Applications
This section provides a block diagram for a typical the 41210 Bridge application. This application
shows a PCI-E adapter card with two Dual 2Gb Fibre Channel controllers. Each of the PCI-X bus
segments is connected to the Dual 2Gb Fibre Channel chip running at 133MHz. The two Dual FC
chips provides the four 2Gb/s outputs.
Figure 4. Intel® 41210 Bridge Adapter Card Block Diagram
SFP Optical
Module
2 Gb/s
2 Gb/s
Dual 2Gb
FC
SFP Optical
Module
I2C Micro
Controller
133 MHz
PCI-X
Intel® 41210
Bridge
SFP Optical
Module
2 Gb/s
2 Gb/s
Dual 2Gb
PCI-X to
PCI Express
FC
SFP Optical
Module
This is locally configurable from SMBus or
PCI-X interfaces (no BIOS support or Drivers
required)
PCI Express
(to Server)
B1491-02
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
13
Download from Www.Somanuals.com. All Manuals Search And Download.
Introduction
This page intentionally left blank.
14
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Package Information
3
3.1
Package Specification
The 41210 Bridge is in a 567-ball FCBGA package, 31mm X 31mm in size, with a 1.27mm ball
pitch.
Figure 5. Top View - 41210 Bridge 567-Ball FCBGA Package Dimensions
Handling
Exclusion
Area
0.550 in.
Die Area
21.00 mm
17.00 mm
0.550 in.
31.00 mm
17.00 mm
21.00 mm
31.00 mm
Pkg_567-Ball_Top
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
15
Download from Www.Somanuals.com. All Manuals Search And Download.
Package Information
Figure 6. Bottom View - 41210 Bridge 567-Ball FCBGA Package Dimensions
AD
AC
AB
AA
Y
W
V
U
T
31.00 – 0.100
- A -
R
4X 0.635
P
N
M
L
K
J
H
G
F
4X 15.500
E
D
C
23X 1.270
B
A
+
1
+
2
4
6
8
10
12
14
16
18
20
22
24
3
5
7
9
11
13
15
17
19
21
23
23X 1.270
8X 14.605
(0.895)
29.2100
31.00 – 0.100
A
0.200
- B -
B2711-01
16
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Package Information
Figure 7. Side View - 41210 Bridge 567-Ball FCBGA Package Dimensions
Detail J
Scale 5:1
H
0.74 – 0.025
0.100 – 0.025
FC BGA Substrate
Die Solder
Bumps
Underfill
Epoxy
Detail H
Scale 5:1
Die
1.170 – 0.085
0.600 – 0.100
J
1.940 – 0.150
BGA Solder Balls
B2712-01
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
17
Download from Www.Somanuals.com. All Manuals Search And Download.
Package Information
This page intentionally left blank.
18
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Power Plane Layout
4
This chapter provides details on the decoupling and voltage planes needed to bias the 41210 Bridge
package.
4.1
41210 Bridge Decoupling Guidelines
decoupling capacitors around the 41210 Bridge ball grid pins.
Figure 8. Decoupling Placement for Core and PCI Express Voltage Planes
B2713-01
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
19
Download from Www.Somanuals.com. All Manuals Search And Download.
Power Plane Layout
Table 2. 41210 Bridge Decoupling Guidelines
41210
Pins
C
(uF)
ESR
(mΩ) (nH)
ESL
# of
Caps
Voltage Plane
Voltage
3.3V
Package
Location
PCI/PCI-X
Voltage
50-
300
1.0-
3.0
Beneath 41210
Bridge BGA
VCC33
VCC33
0.1
1.0
0603
5
As close as design
rules will allow to
41210 Bridge BGA
PCI/PCI-X
Voltage
50-
300
1.0-
3.0
3.3V
0603
2
As close as design
rules will allow to
41210 Bridge BGA
PCI/PCI-X
Voltage
50-
300
1.0-
3.0
3.3V
1.5V
1.5V
VCC33
VCC15
VCC15
10
0.1
1.0
1206
0603
0805
3
5
5
Beneath 41210
Bridge BGA
Core Voltage
Core Voltage
200
200
2.0
2.3
As close as design
rules will allow to
41210 Bridge BGA
As close as design
rules will allow to
41210 Bridge BGA
Core Voltage
1.5V
1.5V
1.5V
VCC15
VCCPE
VCCPE
10
0.1
1
1206
0603
0805
200
200
200
1.9
2.0
2.3
2
3
4
PCI Express
Voltage
Beneath 41210
Bridge BGA
As close as design
rules will allow to
41210 Bridge BGA
PCI Express
Voltage
As close as design
rules will allow to
41210 Bridge BGA
PCI Express
Voltage
1.5V
VCCPE
10
1206
200
1.9
2
4.2
Split Voltage Planes
There are two 1.5V voltage planes that supply power to the 41210 Bridge:
• VCC15:1.5V ±5% (1.5V core voltage)
• VCCPE:1.5V ±3% (1.5V PCI Express voltage)
The 41210 Bridge core (VCC15), PCI-Express (VCCPE) voltages should be supplied by two
separate voltage regulators or a single regulator. If VCC15 and VCCPE is supplied by a single
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
21
Download from Www.Somanuals.com. All Manuals Search And Download.
Power Plane Layout
Note: Linear voltage regulators are recommended when using 1.5 Volt power supplies.
Figure 10. 41210 Bridge Single-Layer Split Voltage Plane
Core
PCI
Express
B2715-01
22
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Reset and Power Timing
Considerations
5
This chapter describes the 41210 Bridge reset timing considerations.
5.1
5.2
A_RST#,B_RST# and PERST# Timing Requirements
The PCI-X Specification requires that there is a 100ms delay from valid power (PERST#) to reset
deassertion (A_RST#/B_RST#). 41210 Bridge will keep A_RST#/B_RST# asserted for a
minimum of 320ms after PERST# is deasserted.
VCC15 and VCC33 Voltage Requirements
The following steps are the power sequencing requirements that must be followed with the
41210 Bridge:
1. The 41210 Bridge requires that the VCC33 voltage rail be no less than 0.5V below VCC15
(absolute voltage value) at all times during 41210 operation, including during system power
up and power down. In other words, the following must always be true:
VCC33 >= (VCC15 – 0.5V)
This can be accomplished by placing a diode (with a voltage drop <0.5V) between VCC15 and
VCC33. A node will be connected to VCC15 and cathode will be connected to VCC33.
If VCC15 (1.5V PCI-X I/O voltage) and VCC15 (1.5V core voltage) are tied together on the
platform, then both voltages must meet the above rule.
Note: Linear voltage regulators are recommended when using 1.5 Volt power supplies.
2. If a voltage regulator solution is used which shunts VCC15 to ground while VCC33 is
powered, the maximum allowable time that VCC15 can be shunted to ground while VCC33 is
fully powered is 20ms.
3. The maximum allowed time between VCC33 and VCC15 ramping is 525ms.
Note: There is no minimum sequencing time requirement other than requirements in Steps 2 and 3.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
23
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Reset and Power Timing Considerations
This page intentionally left blank.
24
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
General Routing Guidelines
6
This chapter provides some basic routing guidelines for layout and design of a printed circuit board
using the 41210 Bridge. The high-speed clocking required when designing with the 41210 Bridge
requires special attention to signal integrity. In fact, it is highly recommended that the board design
be simulated to determine optimum layout for signal integrity. The information in this chapter
provides guidelines to aid the designer with board layout. Several factors influence the signal
integrity of a 41210 Bridge design. These factors include:
• power distribution
• minimizing crosstalk
• decoupling
• layout considerations when routing the PCI Express bus and PCI-X bus interfaces
6.1
6.2
General Routing Guidelines
This section details general routing guidelines for designing with the 41210 Bridge. The order in
which signals are routed varies from designer to designer. Some designers prefer to route all clock
signals first, while others prefer to route all high-speed bus signals first. Either order can be used,
provided the guidelines listed here are followed.
Crosstalk
Crosstalk is caused by capacitive and inductive coupling between signals. Crosstalk is composed of
both backward and forward crosstalk components. Backward crosstalk creates an induced signal on
victim network that propagates in the opposite direction of the aggressor signal. Forward crosstalk
creates a signal that propagates in the same direction as the aggressor signal.
Circuit board analysis software is used to analyze your board layout for crosstalk problems.
Examples of 2D analysis tools include Parasitic Parameters from ANSOFT* and XFS from Quad
Design*. Crosstalk problems occur when circuit etch lines run in parallel. When board analysis
software is not available, the layout should be designed to maintain at least the minimum
recommended spacing for bus interfaces.
• A general guideline to use is, that space distance between adjacent signals be a least 3.3 times
the distance from signal trace to the nearest return plane. The coupled noise between adjacent
traces decreases by the square of the distance between the adjacent traces.
• It is also recommended to specify the height of the above reference plane when laying out
traces and provide this parameter to the PCB manufacturer. By moving traces closer to the
nearest reference plane, the coupled noise decreases by the square of the distance to the
reference plane.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
25
Download from Www.Somanuals.com. All Manuals Search And Download.
General Routing Guidelines
Figure 11. Crosstalk Effects on Trace Distance and Height
Reduce Crosstalk:
- Maximize P
P
H
aggressor
victim
Reference Plane
- Minimize H
A9259-01
• Avoid slots in the ground plane. Slots increases mutual inductance thus increasing crosstalk.
• Make sure that ground plane surrounding connector pin fields are not completely cleared out.
When this area is completely cleared out, around the connector pins, all the return current must
flow together around the pin field increasing crosstalk. The preferred method of laying out a
Figure 12. PCB Ground Layout Around Connectors
Connector
Connector Pins
GND PCB Layer
A. Incorrect method
B. Correct method
A9260-01
6.3
EMI Considerations
It is highly recommended that good EMI design practices be followed when designing with the
41210 Bridge.
• To minimize EMI on your PCB a useful technique is to not extend the power planes to the
edge of the board.
• Another technique is to surround the perimeter of your PCB layers with a GND trace. This
helps to shield the PCB with grounds minimizing radiation.
The below link can provide some useful general EMI guidelines considerations:
26
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
General Routing Guidelines
6.4
Power Distribution and Decoupling
Have ample decoupling to ground, for the power planes, to minimize the effects of the switching
currents. Three types of decoupling are: the bulk, the high-frequency ceramic, and the inter-plane
capacitors.
• Bulk capacitance consist of electrolytic or tantalum capacitors. These capacitors supply large
reservoirs of charge, but they are useful only at lower frequencies due to lead inductance
effects. The bulk capacitors can be located anywhere on the board.
• For fast switching currents, high-frequency low-inductance capacitors are most effective.
Place these capacitors as close to the device being decoupled as possible. This minimizes the
parasitic resistance and inductance associated with board traces and vias.
• Use an inter-plane capacitor between power and ground planes to reduce the effective plane
impedance at high frequencies. The general guideline for placing capacitors is to place high-
frequency ceramic capacitors as close as possible to the module.
6.4.1
Decoupling
Inadequate high-frequency decoupling results in intermittent and unreliable behavior.
A general guideline recommends that you use the largest easily available capacitor in the lowest
inductance package. For specific decoupling requirements for a 41210 Bridge application please
6.5
Trace Impedance
All signal layers require controlled impedance 60 Ω +/- 15%, microstrip or stripline for add-in card
applications. Selecting the appropriate board stack-up to minimize impedance variations is very
important. When calculating flight times, it is important to consider the minimum and maximum
trace impedance based on the switching neighboring traces. Use wider spaces between traces, since
this can minimize trace-to-trace coupling, and reduce cross talk.
When a different stack up is used the trace widths must be adjusted appropriately. When wider
traces are used, the trace spacing must be adjusted accordingly (linearly).
It is highly recommended that a 2D Field Solver be used to design the high-speed traces. The
following Impedance Calculator URL provide approximations for the trace impedance of various
topologies. They may be used to generate the starting point for a full 2D Field solver.
The following website link provides a useful basic guideline for calculating trace parameters:
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
27
Download from Www.Somanuals.com. All Manuals Search And Download.
General Routing Guidelines
Note: Using stripline transmission lines may give better results than microstrip. This is due to the
difficulty of precisely controlling the dielectric constant of the solder mask, and the difficulty in
limiting the plated thickness of microstrip conductors, which can substantially increase cross-talk.
6.5.1
Differential Impedance
The PCI Express standard defines a 100 Ω differential impedance. This section provides some basic
background information on the differential impedance calculations. In the cross section of
Figure 13 shows the cross section of two traces of a differential pair.
Figure 13. Cross Section of Differential Trace
Ground reference plane
B2716 -01
To calculate the coupled impedance requires a 2x2 matrix. The diagonal values in the matrix
represent the impedance of the traces to ground and the off-diagonal values provide a measure of
how tightly the traces are coupled. The “differential impedance is the value of the line-to-line
resistor terminator that optimally terminates pure differential signals.” The two by two matrix is
shown below as:
Figure 14. Two-by-two Differential Impedance Matrix
Z11 Z12
Zo =
Z21 Z22
B2717 -01
For a symmetric trace Z11 = Z22, the differential impedance can be calculated from this equation:
Z
differential = 2(Z11-Z12)
For two traces to be symmetric, they must have the same width, thickness and height above the
ground plane.1 With the traces terminated with the appropriate differential, impedance ringing is
minimized.
1. “Terminating Differential Signals on PCBs”, Steve Kaufer and Kelee Crisafulli, Printed Circuit Design, March 1999
28
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Board Layout Guidelines
7
This chapter provides details on adapter card stackup suggestions. It is highly recommended that
signal integrity simulations be run to verify each 41210 Bridge PCB layout especially if it deviates
from the recommendations listed in these design guidelines.
7.1
Adapter Card Topology
The 41210 Bridge will be implemented on PCI-E adapter cards with an eight layer stackup PCB.
The specified impedance range for all adapter card implementations will be 60Ω +/-15%.
layer geometries for eight layer boards.
Table 3.
Adapter Card Stack Up, Microstrip and Stripline
Nominal Minimum Maximum
Variable
Type
Notes
(mils)
(mils)
(mils)
Solder Mask Thickness (mil)
N/A
N/A
N/A
N/A
0.8
0.6
1.0
Solder Mask E
3.65
2.8
3.65
3.0
3.65
3.2
r
Core Thickness (mil)
Core E
4.3
3.75
4.85
2113 material
r
Power
2.7
1.35
3.5
2.5
1.15
3.3
2.9
1.55
3.7
Plane Thickness (mil)
Ground
1
The trace height will be determined to
achieve a nominal 60 Ω.
Trace Height (mil)
2
3.5
3.3
3.7
3
10.5
4.30
4.30
9.9
11.1
4.85
4.85
Microstrip
Stripline1
3.75
3.75
2113 material
2113 material
Preg E
r
7628 material. Trace height 3 is composed
of one piece of 2113 and one piece of
7628.
Stripline2
4.3
3.75
4.85
Microstrip
Stripline
1.75
1.4
1.2
1.2
2.3
1.6
Trace Thickness (mil)
Trace Width (mil)
Microstrip
Stripline
FR4
4.0
4.0
2.5
2.5
5.5
5.5
Total Thickness (mil)
62.0
56.0
68.0
Trace Spacing (using
microstrip E2E/C2C)
[12]/[16]
[12]/[16]
Trace Spacing (using
stripline E2E/C2C)
Microstrip
Stripline
60
60
51
51
69
69
Trace Impedance
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
29
Download from Www.Somanuals.com. All Manuals Search And Download.
Board Layout Guidelines
NOTE: Each interface will set the trace spacing based on its signal integrity of differential impedance
requirements. For the purposes of the building the transmission line models, it is assumed the artwork is
very accurate and therefore a constant. Thus, all the variability in the trace spacing is the result of the
tolerances of the trace width.
Figure 15. Adapter Card Stackup
Microstrip
Trace
Width
Microstrip
Trace
Spacing
Microstrip Trace Thickness
Solder Mask Thickness
L1
L1
Trace Height 1
L2 (GND)
Trace Height 2
Stripline Trace Thickness
L3
L3
Trace Height 3
L4 (VCC)
L5 (VCC)
Core Thickness
Plane Thickness
L4
L4
L7 (GND)
L8
Stripline
Trace
Stripline
Trace
Width
Spacing
B1436-01
30
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8
This chapter describes several factors to be considered with a 41210 Bridge PCI/PCI-X design.
These include the PCI IDSEL, PCI RCOMP, PCI Interrupts and PCI arbitration.
8.1
Interrupts
PCI Express provides interrupt messages that emulate the legacy wired mechanism. This allows IO
devices to signal PCI-style interrupts using a pair of ASSERT and DEASSERT messages This
message pairing preserves the level-sensitive semantics of the PCI interrupts on PCI Express.
The 41210 Bridge uses four interrupts - A_INTA:A_INTD on bus A segment and four interrupts
B_INTA:B_INTD that corresponding to the four interrupts defined in the PCI specification. The
41210 Bridge routes its PCI interrupt pins and the internal interrupts, to PCI Express INTx
Table 4. INTx Routing Table
A_INT# Interrupt Pins
B_INT# Interrupt Pins
B_INTA
PCI Express INTx Message
INTA
A_INTA
A_INTB
A_INTC
A_INTD
B_INTB
B_INTC
B_INTD
INTB
INTC
INTD
The 41210 Bridge will use its primary bus number and device number in the Requester ID field for
the PCI Express INTx messages. As stated in the PCI Express specification, the function number is
reserved for interrupt messages and will always be 0.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
31
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
Note: PCI Express Assert_INTx/Deassert_INTx messages are not inhibited by the BME bit.
8.1.1
Interrupt Routing for Devices Behind a Bridge
performance (by reducing interrupt sharing), adapter boards have to select the appropriate
A_INTX#, B_INTX# (where X is A, B, C or D) input pin to use on each PCI bus segment. The
chosen interrupt input also imposes a PCI device number requirement for the interrupt source as
Table 5. Interrupt Binding for Devices Behind a Bridge
Device Number on
Interrupt Pin on Device
Secondary Bus
Interrupt on 41210 Bridge
INTA#
INTA#
INTB#
INTB#
INTC#
INTD#
INTB#
INTC#
INTD#
INTA#
INTC#
INTD#
INTA#
INTB#
INTD#
INTA#
INTB#
INTC#
a
b
- . 4, 8 , 12, 16, 20, 24, 28
INTC#
INTD#
INTA#
INTB#
INTC#
INTD#
INTA#
INTB#
INTC#
INTD#
INTA#
INTB#
INTC#
INTD#
b
1, 5, 9 , 13, 17, 21, 25, 29
b
2, 6, 10 , 14, 18, 22, 26, 30
b
3, 7, 11 , 15, 19, 23, 27, 31
a.
b.
Device number 0 is reserved for the Bridge and should not be assigned to secondary devices.
AD[27:24] which correspond to devices 11:8 should not be used for IDSEL# connections as these signals are used
when accessing the extended configuration space in the bridge from the secondary bus.
8.2
PCI Arbitration
The 41210 Bridge supports a high-performance internal PCI arbiter that supports up to seven
masters on each PCI segment A and B PCI Buses. The request inputs into the internal arbiter
include: six external request inputs and 1 internal request input. All request inputs to the internal
arbiter are split into two groups, a high priority group and a low priority group. Any master,
including the internal master, can be programmed to be in either of the two groups. This could also
mean that all the request inputs into the arbiter could be in one single group. Within a group,
priority is round-robin. The entire low-priority group represents one slot in the high priority group.
The 41210 Bridge provides a 16-bit arbiter control register to control two aspects of the internal
arbiter behavior:
32
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
• Priority group for a master (i.e., whether a master is in low priority group or high priority
group).
• Bus parking on last PCI agent or the bridge.
By default the arbiter parks the bus on the bridge and drives the A/D, C/BE# and PAR lines to a
known value while the bus is idle.
8.2.1
PCI Resistor Compensation
Figure 16 provides the recommended resistor compensation pin termination for the PCI A and PCI
B buses.
Figure 16. PCI RCOMP
RCOMP
100
Ω
– 1%
B2718 -01
8.3
PCI General Layout Guidelines
For acceptable signal integrity with bus speeds up to 133 MHz it is important to PCB design layout
to have controlled impedance.
• Signal traces should have an unloaded impedance of 60 +/- 10% Ω.
• Signal trace velocity should be roughly 150 – 190 ps/inch
There are a couple of general guidelines which should be used when routing your PCI bus signals:
• Avoid routing signals > 8”.
• The following signals have no length restrictions: A_INTA#, A_INTB#, A_INTC#,
A_INTD#, B_INTA#, B_INTB#, B_INTC#, B_INTD# and TCK, TDI, TDO, TMS and
TRST#. Most PCI-X signals are timing critical. These signals have length restrictions for
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
33
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
Table 6. PCI-X Signals
A PCI Bus Segment:
A_ACK64#, A_AD[63:0], A_CBE_[7:0]#, A_DEVSEL#, A_FRAME#,
A_GNT_[5:0]#, A_IRDY#, A_LOCK#, A_PAR64, A_REQ64#, A_REQ_[5:0]#,
A_STOP#, A_TRDY#, A_CLKO[6:0], A_CLKI
Timing Critical Signals
B PCI Bus Segment:
B_ACK64#, B_AD[63:0], B_CBE_[7:0]#, B_DEVSEL#, B_FRAME#,
B_GNT_[5:0]#, B_IRDY#, B_LOCK#, B_PAR64, B_REQ64#, B_REQ_[5:0]#,
B_STOP#,B_TRDY#, B_CLKO[6:0], B_CLKI
A PCI Bus Segment:
A_RST#, A_PME#
B PCI Bus Segment:
B_RST#, B_PME#
Reset Signals
A PCI Bus Segment:
A_133EN, A_IRQ[15:0]#, A_M66EN, A_PCIXCAP, A_PERR#, A_SERR#
B PCI Bus Segment:
Non Timing Critical
Signals
B_133EN, B_IRQ[15:0]#, B_M66EN, B_PCIXCAP, B_PERR#, B_SERR#
Table 7. PCI/PCI-X Frequency/Mode Straps
A_M66EN,
B_M66EN
A_133EN,
B_133EN
(on board)
Bus
Mode/
Freq
A_PCIXCAP, B_PCIXCAP
0
0
0
1
X
X
PCI 33
PCI 66
PCI-X 66MHz cards connect this
signal to ground through a 10KΩ
±5% resistor in parallel with a
0.01uF ±10% capacitor.
X
X
PCI-X 66
PCI-X 133 MHz cards connect
PCIXCAP to ground through a
0.01uF ±10% capacitor.
X
X
0
1
PCI-X 100
PCI-X 133
PCI-X 133 MHz cards connect
PCIXCAP to ground through a
0.01uF ±10% capacitor.
Note: All signals sampled on the rising edge of PERST#.
8.3.1
PCI Pullup Resistors Not Required
PCI control signals on the 41210 Bridge do NOT require pullup resistors on the adapter card to
ensure that they contain stable values when no agent is actively driving the bus. These include:
A_ACK64#, A_AD[63:32], A_CBE#[7:4], A_DEVSEL#, A_FRAME#, A_INTA#, A_INTB#,
A_INTC#, A_INTD#, A_IRDY#, A_PERR#, A_PAR, A_GNT#[5:0], A_REQ#[5:0], A_LOCK#,
A_PAR64, A_REQ64#, A_SERR#, A_STOP#, A_TRDY#, B_ACK64#, B_AD[63:32],
34
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
B_CBE#[7:4], B_DEVSEL#, B_FRAME#, B_INTA#, B_INTB#, B_INTC#, B_INTD#,
B_IRDY#, B_PERR#, B_PAR, B_GNT#[5:0], B_REQ#[5:0], B_LOCK#, B_PAR64, B_REQ64#,
B_SERR#, B_STOP#, and B_TRDY#.
8.4
PCI Clock Layout Guidelines
The PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0b compliant, allows a
maximum of 0.5 ns clock skew timing for each of the PCI-X frequencies: 66 MHz, 100 MHz and
133 MHz. A typical PCI-X application may require separate clock point-to-point connections
distributed to each PCI device. The 41210 Bridge provides seven buffered clocks on the PCI bus to
length matching requirements. These same guidelines apply to the 41210 Bridge PCI “B” clock
outputs. The recommended clock buffer layout are specified as follows:
• Match each of the used the 41210 Bridge output clock lengths A_CLK[6:0] and B_CLK[6:0]
to within 0.1” to help keep the timing within the 0.5 ns maximum budget.
• Keep the distance between the clock lines and other signals “d” at least 25 mils from each other.
• Keep the distance between the clock line and itself “a” at a minimum of 25 mils apart (for
serpentine clock layout).
• A_CLKIN gets connected to A_CLKO6 through a 22Ω +/- 1% resistor and likewise for
B_CLKIN is connected to B_CLKO6 through a 22Ω resistor.
• The 22 +/- 1% Ω resistor is within 500 mils of A_CLKO.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
35
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
Figure 17.
PCI Clock Distribution and Matching Requirements
22
X0
X1
PCI
Device 1
A_CLKIN
a
Intel®
41210
Bridge
A_CLKO0
A_CLKO1
A_CLKO2
A_CLKO3
22
PCI
Device 2
d
22
A_CLKO4
PCI
Device 3
X2
X3
X4
A_CLKO6
22
PCI
Device 4
22
22
PCI
Device 5
Notes:
– PCI Clock Lengths X0, X1, X2, X3 and X4 should be matched within 0.1 inch of each other.
– Minimum separation between two different CLKs, "d".
– Minimum separation between two segments of the same CLK line, "a".
B1499-04
36
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
Table 8.
PCI-X Clock Layout Requirements Summary
Parameter
Routing Guidelines
Signal Group
PCI Clocks B_CLKO[6:0], A_CLK[6:0]
Route over unbroken ground or power plane
4 mils
Reference Plane
Stripline Trace Width
Stripline Trace Spacing: Separation between two
different clock lines, “d” clock lines
25 mils center to center from any other signal
25 mils center to center from any other signal
50 mils center to center from any other signal
Stripline Trace Spacing: Separation between two
segments of the same clock line (on serpentine
layout), “a” dimension
Stripline Trace Spacing: Separation between clocks
and other lines
All 41210 Bridge Output Clocks B_CLK0[6:0] and
A_CLK[6:0] connected to devices must be length
matched to 0.1 inch of each other.
Length Matching Requirements
The clock feedback line lengths from A_CLKOUT to
A_CLKIN and B_CLKOUT to B_CLKIN should be
length matched to all other clock lines within 0.1”.
Total Length of the 41210 Bridge PCI CLKs on the
adapter card
10” -14”
Connect A_CLKIN to one end of a 22Ω +/- 1% resistor
and the other end connected to A_CLKOUT and
connect B_CLKIN to one end of a 22Ω resistor and
the other end connected to B_CLKOUT
A_CLKIN, B_CLKIN Series Termination
Each of the clock outputs A_CLKO[6:0] and
A_CLK[6:0], B_CLK[6:0] Series Termination
B_CLK[6:0] should have series 22Ω resistor located
within 500 mils of the 41210 Bridge clock output.
Point to point signal routing should be used to keep
the reflections low.
Routing Guideline 1
Routing Guideline 2
Minimize number of vias
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
37
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.5
PCI-X Topology Layout Guidelines
The PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0b compliant, recommends
the following guidelines for the number of loads for your PCI-X designs. Any deviation from these
maximum values requires close attention to layout with regard to loading and trace lengths.
Table 9.
PCI-X Slot Guidelines
Frequency
Maximum Loads
Maximum Number of Slots
66 MHz
100 MHz
133 MHz
8
4
2
4
2
1
8.6
Intel® 41210 Serial to Parallel PCI Bridge Design
Guide Layout Analysis
The following sections describes layout recommendations based on the presilicon signal integrity
analysis. This analysis was conducted using the following parameters:
• Card stack up: 60 Ω +/- 15% single-ended impedance
• Driver Model 41210 Bridge IBIS
• Receiver Model: generic models for PCI-X and PCI
• Driver Package Model: Preliminary 41210 Bridge Model
• Cross talk and ISI impact on timing were not modeled
38
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.6.1
Embedded PCI-X 133 MHz
Figure 18. Embedded PCI-X 133 MHz Topology
EM1
TL1
EM2
B2719 -01
Table 10.
Embedded PCI-X 133 MHz Routing Recommendations
Parameter
Reference Plane
Routing Guideline for Lower AD Bus
Route over an unbroken ground plane
60 Ω +/- 15%
Board Impedance
Stripline Trace Spacing
Microstrip Trace Spacing
Break Out
12 mils from edge to edge
18 mils, from edge to edge
5 mils on 5 mils spacing. Maximum length of breakout region can be 500 mils
Spacing from other groups: 25 mils min, edge to edge
Group Spacing
Trace Length 1 (TL1): From
41210 Bridge signal Ball to
first junction
1.75” min - 4.0” max
Trace Length 3 junction of
TL_EM1 and TL_EM2 to the 1.25” min - 3.25” max
embedded device
Length Matching
Requirements:
Clocks coming form the clock driver must be on the same layer and length
matched to within 25 mils.
Number of vias
3 vias max per path
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
39
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.6.2
Embedded PCI-X 100 MHz
Figure 19. Embedded PCI-X 100 MHz Topology
TL_EM1
EM1
TL_EM3
TL_EM2
EM3
EM2
TL1
B2720 -01
Table 11.
Embedded PCI-X 100 MHz Routing Recommendations
Parameter
Reference Plane
Routing Guideline for Lower AD Bus
Route over an unbroken ground plane
Board Impedance
Stripline Trace Spacing
Microstrip Trace Spacing
Break Out
60 Ω +/- 15%
12 mils from edge to edge
18 mils, from edge to edge
5 mils on 5 mils spacing. Maximum length of breakout region can be 500 mils
Spacing from other groups: 25 mils min, edge to edge
Group Spacing
Trace Length 1 (TL1): From
41210 Bridge signal Ball to
first junction
0.5” min - 3.0” max
2.5” min - 3.5” max
Trace Length: TL_EM1: from
41210 Bridge signal ball to
the first embedded device
Trace Length TL_EM2 -
TL_EM3: from junction to the 1.5” min - 3.5” max
embedded device
Length Matching
Requirements:
Clocks coming form the clock driver must be on the same layer and length
matched to within 25 mils.
Number of vias
4 vias max per path
40
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.6.3
PCI-X 66 MHz Embedded Topology
application.
Figure 20.
PCI-X 66 MHz Embedded Routing Topology
EM1
EM3
EM5
EM7
TL1
TL2
TL3
TL4
EM2
EM4
EM6
EM8
B2721 -01
Table 12.
PCI-X 66 MHz Embedded Routing Recommendations
Parameter
Reference Plane
Routing Guideline for Lower AD Bus
Route over an unbroken ground plane
Board Impedance
Stripline Trace Spacing
Microstrip Trace Spacing
Break Out
60 Ω +/- 15%
12 mils edge to edge
18 mils, edge to edge
5 mils on 5 mils. Maximum length of breakout region can be 500 mils
Spacing from other groups: 25 mils min, edge to edge
Group Spacing
Trace Length 1 (TL1): From
41210 Bridge signal Ball to
first junction
1.0” - 5.0” max
Trace Length TL2 to TL4 -
between junctions
1.0” min - 2.5” max
Trace Length TL_EM1 to
TL_EM8 from junction
connector to the embedded
device
2.0” min - 3.0” max
Length Matching
Requirements:
Clocks coming form the clock driver must be length matched to within 25 mils
and routed identical in layers.
Number of vias
4 vias max.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
41
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.6.4
PCI 66 MHz Embedded Topology
design.
Figure 21. PCI 66 MHz Embedded Topology
EM1
EM3
TL1
TL2
EM2
EM4
B2722 -01
Table 13.
PCI 66 MHz Embedded Table
Parameter
Routing Guideline for Lower AD Bus
Reference Plane
Route over an unbroken ground plane
60 Ω +/- 15%
Board Impedance
Microstrip Trace Spacing
Stripline Trace Spacing
Group Spacing
18 mils center to center
12 mils center to center
Spacing from other groups: 25 mils min, edge to edge
5 mils on 5 mils spacing. Maximum length of breakout
region can be 500 mils.
Breakout
Trace Length 1 TL1: From 41210 Bridge signal Ball
to first junction
5.0” max
Trace Length TL2 between junctions
0.5” min - 3.5” max
2.0” min - 3.0” max
Trace Length TL_EM1 to TL_EM4 from junction to
embedded devices
Clocks coming from the clock driver must be length
matched to within 25 mils.
Length Matching Requirements
Number of vias
4 vias max.
P
42
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
8.6.5
PCI 33 MHz Embedded Mode Topology
design.
Figure 22. PCI 33 MHz Embedded Mode Routing Topology
EM1
EM3
EM5
EM7
EM9
TL1
TL2
TL3
TL4
TL5
EM2
EM4
EM6
EM8
EM10
B2723 -01
Table 14.
PCI 33 MHz Embedded Routing Recommendations
Parameter
Reference Plane
Routing Guideline for Lower AD Bus
Route over an unbroken ground plane
Board Impedance
Stripline Trace Spacing
Microstrip Trace Spacing
Group Spacing
60 Ω +/- 15%
12 mils, edge to edge
18 mils edge to edge
Spacing from other groups: 25 mils min, edge to edge
Breakout
5 mils on 5 mils spacing. Maximum length of breakout region can be 500 mils.
Trace Length 1 TL1: From
41210 Bridge signal Ball to
first junction
5.0” max
Trace Length TL2 to TL5 -
between junctions
0.5” min - 3.5” max
Trace Length TL_EM1 to
TL_EM10 from junction to
embedded devices
2.0” min - 3.0” max
Length Matching
Requirements
Clocks coming from the clock driver must be length matched to within 25 mils.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
43
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI-X Layout Guidelines
This page intentionally left blank.
44
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI Express Layout
9
This section provides an overview of the PCI-Express stackup recommended based on Intel
presimulation results. For additional information, refer to the Intel® 41210 Serial to Parallel PCI
Bridge Developer’s Manual or the PCI Express Specification, Revision 1.0a from the
www.pcisig.com website.
9.1
General recommendations
PCI Express is a serial differential low-voltage point-to-point interconnect. The PCI Express was
designed to support 20 inches between components with standard FR4. The 41210 Bridge supports
x8 lanes. PCI-Express requires special considerations be made for interconnect losses, jitter, crosstalk
and mode conversions. The below list provides some general guidelines for the layout of a PCI-
Express trace:
1. Jitter: Trace lengths of a PCB trace can introduce around 1 to 5 ps of jitter and 0.35 to 0.5 dB
of loss per inch of differential pair. An add-in card the trace length from edge-finger pad to
device is limited to 3 inches.
2. Matching within pair: Trace lengths of matching differential pairs are required to be matched
within +/-5 mil delta. Each net within a differential pair should be length matched on a
segment-by-segment basis at point of discontinuity such as an breakout area, routes between
vias, routes between AC coupling capacitors and connector pins.
3. Trace Symmetry: Trace Symmetry is required between two traces of the same differential pair.
4. Vias: Vias contribute 0.5 to 1.0 dB/via toward the loss budget. Vias on an add-in card should
be limited to one near the breakout section of the pads and one near the edge finger.
5. Bends: Trace bends should be kept to a minimum. If bends are used they should be at a 45-
degree angle or smaller. The number of left and right bends should be matched as closely as
possible to even out the overall lengths of each segment of the differential pair.
6. AC Coupling capacitors: AC coupling capacitor with a value of 75nF to 200nF should line
up at the same location from one trace to the other within the pair. The 0402 size capacitor
with a small pad size is highly recommended. The breakout from the capacitor should be
symmetrical for both signal traces in the differential pair.
7. Connector pins: Length compensation for the connector pins of the differential pair being
offset from each other the PCB trace should be considered.
8. Ground Plane Referencing: Ground plane referencing is required along the entire route of the
differential pair. Traces routed near the edge should maintain a 40 mil air gap to the edge.
Layer switching should also maintain the ground plane. Grounds between planes should be
connected with stitching vias (with one to three recommended per differential pair).
9. Breakout Areas: Breakout areas near a device package should be limited to 500 mils in lengths.
The necking down to a smaller trace width should be symmetrical on the differential pair.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
45
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI Express Layout
9.2
PCI-Express Layout Guidelines
The layout guidelines for PCI-Express were developed for an adapter card topologies. The models and
assumptions used in development of these guidelines were as follows:
• Add-In Card Stackup: 60 Ω single-ended impedance
• Target Differential Impedance: 100 Ω +/- 20%.
• Driver Model: 41210 Bridge PCI-E IBIS
• Receiver Model: 41210 Bridge PCI-E IBIS. Specification model did not meet specifications
• Driver Package Model: Preliminary 41210 Bridge model.
• No receiver package model used since specification eye is at package pin.
• Assumed that traces in a lane could be routed totally on microstrip, totally on stripline, or a
mixture of microstrip and stripline.
• AC coupling capacitors were modeled as a parasitic resistor and inductor in series.
• Add-in card was modeled as micro-strip routes only.
• No vias were modeled at this time.
• Only the receiver eye was evaluated. The next revision will evaluate the eye at the transmitter
and connector as well as the receiver.
9.3
Adapter Card Layout Guidelines
Table 15.
Adapter Card Routing Recommendations (Sheet 1 of 2)
Parameter
Reference Plane
Routing Guidelines
Route over an unbroken ground plane
Target Single Ended
Impedance
60 Ω nominal
Target Differential
Impedance
100 Ω +/- 20% Differential Impedance
Microstrip and Stripline Trace
Width
4 mils
Intrapair: 10 mils center-to-center
Interpair: 30 mils center-to-center
22 mils. center to center (pair to pair).
Microstrip Trace Spacing
Group Spacing
Transmit and Receive pairs should be interleaved. If no interleaving, then inter
pair spacing should be increased to 50 mils (c2c). Center to center of inter pair is
defined as center of Positive of one pair to Center of Negative of the next or vice
versa
Spacing from other groups: 25 mils minimum, center to center
Transmit Trace Length
(41210 Bridge signal pin to
AC coupling capacitor.)
0.25”- 5.0” max
Transmit Trace Length (AC
coupling capacitor to card
edge finger.)
1.00”- 4.5” max
46
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI Express Layout
Table 15.
Adapter Card Routing Recommendations (Sheet 2 of 2)
Receive Trace Length (Card
edge finger to 41210 Bridge 1.0” min - 6.0” max
receiver pin
Total allowable intra-pair length mis-match must not exceed 25 mils. Each
routing segment should be matched as close as possible. Total skew across all
lanes must be less than 20 ns. See the PCI-Express Desktop Design Guidelines
for additional routing requirements
Length Matching
Requirements:
Number of vias
4 max
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
47
Download from Www.Somanuals.com. All Manuals Search And Download.
PCI Express Layout
This page intentionally left blank.
48
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
10
This chapter describes 41210 Bridge circuit implementations.
10.1
41210 Bridge Analog Voltage Filters
The Intel® 41210 Serial to Parallel PCI Bridge requires several external analog voltage filter
circuits to be placed on the system board, three for the PCI interface, one for the PCI Express
interface, and one for the bandgap voltage. The 41210 Bridge lists the recommended filter values
for these filter circuits -- any one of the filter circuits can use any one of the four R, L and C
Express analog voltage filter.
Table 16.
Recommended R, L and C Values for 41210 Bridge Analog Filter Circuits
Config
1
R
L
C
4.7uH ±25%
PCI, PCI-E: 45mA
Bandgap: 30mA
0.5Ω ±1%
1/16W
33uF ±20%
6.3V
4.7uH ±20
0.5Ω ±1%
1/16W
22uF ±20%
6.3V
2
3
PCI, PCI-E: 45mA
Bandgap: 30mA%
4.7uH ±20%
PCI, PCI-E: 45mA
Bandgap: 30mA
0.5Ω ±1%
1/16W
2x10uF ±20%
6.3V
4.7uH ±20%
PCI: 45mA
1.0Ω ±1%
1/16W
10uF ±20%
6.3V
a
4
Bandgap: 30mA
a.
Configuration number 4 cannot be used for the PCI Express analog voltage filter.
Additional notes:
L (Inductor)
— L must be magnetically shielded
— ESR: max < 0.4Ω
— rated at 45mA (or 30mA for bandgap circuit only)
C (Capacitor)
— ESR: max < 0.5Ω
— ESL < 3.0nH
R (Resistor)
— 1/16W
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
49
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
10.1.1
PCI Analog Voltage Filters
The following filter circuit is recommended for the PCI interface. Three separate, identical
versions of this circuit should be placed on the system board, one for each VCCAPCI[2:0] pin on
the Intel® 41210 Serial to Parallel PCI Bridge.
Figure 23. PCI Analog Voltage Filter Circuit
Board Trace:
Breakout Trace:
Trace Width > 25 mils
Trace Spacing < 10 mils
Trace Length < 600 mils
Trace Width > 6 mils
Trace Spacing < 6 mils
Trace Length < 600 mils
Board Route Breakout
Traces Traces
VCC
L
VCCAPCI[2:0]
R
Intelfi 41210
Bridge
C
VSS
B2724 -01
Note: Three of these PCI filter circuits must be placed on the system board, one for each of the
VCCAPCI[2:0] pins on the Intel® 41210 Serial to Parallel PCI Bridge.
• Place C as close as possible to package pin.
• R must be placed between VCC15 and L.
• Route VCCPCI[x] and VSS as differential traces.
• VCCPCI[x] and VSS traces must be ground referenced (No VCC15 references).
• Max total board trace length = 1.2”.
• Min trace space to other nets = 30 mils.
10.1.2
PCI Express Analog Voltage Filter
50
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
Figure 24.
PCI Express Analog Voltage Filter Circuit
Board Trace:
Breakout Trace:
Trace Width > 25 mils
Trace Spacing < 10 mils
Trace Length < 600 mils
Trace Width > 6 mils
Trace Spacing < 6 mils
Trace Length < 600 mils
Board Route Breakout
Traces Traces
VCC
L
VCCAPE
R
Intelfi 41210
Bridge
C
VSSAPE
B2725 -01
Note:
.
• Place C as close as possible to package pin.
• R must be placed between VCC15 and L.
• Route VCCAPE and VSSAPE as differential traces.
• VCCAPE and VSSAPE traces must be ground referenced (No VCC15 references).
• Max total board trace length = 1.2”.
• Min trace space to other nets = 30 mils.
10.1.3
Bandgap Analog Voltage Filter
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
51
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
Figure 25.
Bandgap Analog Voltage Filter Circuit
Board Trace:
Breakout Trace:
Trace Width > 25 mils
Trace Spacing < 10 mils
Trace Length < 600 mils
Trace Width > 6 mils
Trace Spacing < 6 mils
Trace Length < 600 mils
Board Route Breakout
Traces Traces
2.5 V
L
VCCBGPE
R
Intelfi 41210
Bridge
C
VSS
VSSBGPE
Note: Ground VSSBGPE at capacitor
B2726 -01
Note:
.
• Place C as close as possible to package pin.
• R must be placed between the 2.5V supply and L.
• Route VCCBGPE and VSSBGPE as differential traces.
• VCCBGPE and VSSBGPE traces must be ground referenced (No 2.5V references).
• VSSBGPE should be grounded at the capacitor.
• Max total board trace length = 1.2”.
• Min trace space to other nets = 30 mils.
52
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
10.2
Intel® 41210 Serial to Parallel PCI Bridge Reference
and Compensation Pins
There are three compensation pins on Intel® 41210 Serial to Parallel PCI Bridge.
PE_RCOMP[1:0] are two separate pins that provide voltage compensation for the PCI Express
interface on the Intel® 41210 Serial to Parallel PCI Bridge. The nominal compensation voltage is
0.5V. An external 24.9Ω ±1% pullup resistor should be used to connect to VCC15. A single pullup
resistor can be used to for both of these signals.
RCOMP is an analog PCI interface compensation pin, providing 0.75V to the Intel® 41210 Serial
to Parallel PCI Bridge. A 100Ω ±1% pulldown resistor should be used to connect the RCOMP pin
to ground.
Figure 26. Reference and Compensation Circuit Implementations
VCC
Intelfi 41210
Bridge
R1 = 24.9 Ω – 1%
0.5 V
0.5 V
PE_RCOMP[0]
PE_RCOMP[1]
0.75 V
RCOMP
R3 = 100 Ω – 1%
B2727 -01
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
53
Download from Www.Somanuals.com. All Manuals Search And Download.
Circuit Implementations
10.2.1
SM Bus
The SMBus interface does not have configuration registers. The SMBus address is set by the states
Table 17.
SMBUs Address Configuration
Bit
Value
7
6
5
4
3
2
1
1
1
SMBUS[5]
0
SMBUS[3]
SMBUS[2]
SMBUS[1]
Refer to Section 2.4 for details on how to use the SMBus to initialize 41210 Bridge registers with a
microcontroller.
54
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Customer Reference
Boards
11
This chapter describes the 41210 Bridge Customer Reference Board (CRB).
11.1
Board Stack-up
The proposed layout of the PCB is eight layers with the following stackup:
• Signal #1 (Top/Component Side)
• Ground Plane: GND
• Signal #2
• Power Plane
• Power Plane
• Signal #3
• Ground Plane
• Signal #4 (Bottom)
The permittivity constant Er = 4.5
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
55
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Customer Reference Boards
Table 18. CRB Board Stackup
Thickness
(mils)
Layer
Type
Copper Weight
1
Signal
Prepreg
Plane: GND
Core
2.00
4.50
1.20
4.80
1.20
14.00
1.20
3.8
1/2 + plating
2
3
4
5
6
7
8
1
Signal
1
Prepreg
Plane: PWR
Core
1
Plane: PWR
Prepreg
Signal
1.20
14.00
1.20
4.80
1.20
4.50
2.00
1
1
Core
Plane: Power
Prepreg
Signal
1
1/2 + plating
Est. Total
Thickness
62 +/- 7
11.2
11.3
Material
The following materials are used with the 41210 Bridge CRB:
• FR-4, 0.062 in. +/- .007, 1.0 oz Copper Power/GND.
• Full length PCI Raw Card (3.3V Universal) 6.2” high x 7.00” long max with ½ inch cut away.
Impedance
Most signal layers require controlled Impedance of 60 Ω +/- 5% microstrip or stripline where
appropriate.
Differential signals for the PCI-E interface require matched 100 Ω differential termination realized
as matched 50Ω resistances referenced to ground.
56
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Customer Reference Boards
11.4
Board Outline
Figure 27 provides the mechanical outline of the 41210 Bridge CRB.
Figure 27. Mechanical Outline of the 41210 Bridge
U1
Intelfi 41210
Bridge
B2728 -01
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
57
Download from Www.Somanuals.com. All Manuals Search And Download.
41210 Bridge Customer Reference Boards
This page intentionally left blank.
58
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
12
This checklist highlights design considerations that should be reviewed prior to manufacturing an
adapter card that implements the 41210 Bridge product. The items contained within this checklist
attempt to address important connections to these devices and any critical supporting circuitry. This
is not a complete list and does not guarantee that a design will function properly.
Table 19. PCI Express Interface Signals
Signals
Recommendations
Reason/Impact
Must be connected to clock from a PCI Express
connector for add-in card designs or to a 100MHz
oscillator for an embedded design.
REFCLKn,
REFCLKp
24.9Ω ±1% pullup resistor to 1.5V. A single resistor can
PE_RCOMP[1:0] be used for both signals. Place resistor as close as
possible to REFCLKn, REFCLKp pins.
PCI Express compensation pin.
0.5V nominal.
For X1 mode, only signals PERp[0] and PERn[0] or
PERp[7] and PERn[7] are used.
PCI Express data serial inputs
(differential data receive
signals).
PERP[7:0]
PERN[7:0]
For X4 mode, only signals PERp[3:0] and PERn[3:0]
are used.
For X8 mode, all of these signals, PERp[7:0] and
PERn[7:0], are used.
For X1 mode, only signals PETp[0] and PETn[0] or
PETp[7] and PETn[7] are used.
PCI Express data serial inputs
(differential data transmit
signals).
PETP[7:0]
PETN[7:0]
For X4 mode, only signals PETP[3:0] and PETN[3:0]
are used.
For X8 mode, all of these signals, PETP[7:0] and
PETN[7:0], are used.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
59
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
Table 20. PCI/PCI-X Interface Signals
Signals
Recommendations
Reason/Impact
X_AD[63:32]
X_CBE[7:4]#
X_DEVSEL#
X_FRAME#
X_IRDY#
X_TRDY#
X_STOP#
X_PERR#
X_SERR#
X_REQ[5:0]#
X_GNT[5:0]#
X_LOCK#
X_PAR
41210 Bridge has internal pullup
resistors on these signals.
No external pullup resistors required on system board.
X_AD[31:0] and X_CBE#[3:0]
signals do not require pullups
according to the PCI Specification.
X_PAR64
X_ACK64#
X_REQ64#
Only relevant when running in PCI-X Mode
(X_PCIXCAP = 1).
Determines the max PCI-X Mode 1 frequency for a
particular segment (100 MHz or 133 MHz):
A_133EN
B_133EN
Sampled on the rising edge of
PERST#.
0 = 100 MHz PCI-X max frequency
1 = 133 MHz PCI-X max frequency
Use an 8.2KΩ pullup resistor to VCC33. This resistor is
located on the system board.
A_INTA#,
A_INTB#,
A_INTC#,
A_INTD#,
B_INTA#,
B_INTB#,
B_INTC#,
B_INTD#
The 41210 Bridge has internal
pullup resistors on these signals.
No pullup resistors required on these signals.
60
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
Table 20. PCI/PCI-X Interface Signals
Signals
Recommendations
Reason/Impact
Controls frequency of the PCI segment when running
in conventional PCI mode (33 MHz or 66 MHz):
0 = 33 MHz PCI
1 = 66 MHz PCI
•
•
Pull-up using a 8.2KΩ resistor when the PCI bus is
to operate at 66 MHz and not already pulled up by
system board. This signal is grounded for 33 MHz
operation.
A_M66EN
B_M66EN
Sampled on the rising edge of
PERST#.
Connect M66EN to a 0.01 µF capacitor located
with-in 0.25 inches of the M66EN pin on the PCI
connector (for designs with secondary PCIX bus
slots only).
•
Design without secondary PCI/PCI-
X Slot
—
If there is at least one legacy
PCI device on the PCI/PCI-X
bus, tie this pin directly to
GND.
—
If all devices are PCI-X
capable and there is at least
one PCI-X device that only
supports maximum PCI-X
66MHz on the secondary PCI
bus, pull down to GND
through 10KΩ series resistor
parallel with a 0.01uF
capacitor.
—
If all secondary PCI-X
devices (and the bus loading)
support PCI-X 133MHz,
connect PCIXCAP to 3.3V
through an 8.2K Ω resistor
A_PCIXCAP
B_PCIXCAP
Connects directly to the PCIXCAP pin on the PCI slot.
Connect to VCC33 through an 8.2KΩ pullup resistor.
•
Design with secondary PCI/PCI-X
Slot
—
If there is at least one on
board legacy PCI device on
the secondary PCI bus, tie
this pin directly to GND.
—
Else
•Pull up to 3.3V through a
8.2KΩ resistor
•Connect this pin to
PCIXCAP (Pin B38) of the
PCI connector. (Assuming
bus loading supports up to
PCI-X 133MHz)
IDSEL
The series resistor on IDSEL should be 200Ω ±5%.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
61
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
Table 21. Miscellaneous Signals
Signals
Recommendations
Reason/Impact
Used for debug purposes. Connect to VCC33 through
an 8.2KΩ pullup resistor for normal operation.
RSTIN#
A_STRAP0,
A_STRAP1,
A_STRAP2,
A_STRAP6,
These signals REQUIRE external pull-downs to GND
on the board 8.2KΩ unless otherwise stated.
B_STRAP0,
B_STRAP1,
B_STRAP2,
B_STRAP6
RESERVED [8:1]
Input pin to configure 41210 to retry configuration
accesses on it's PCI Express interface.
CFGRETRY
•
To retry configuration accesses to the 41210, pull high to
3.3V through a 2K Ω resistor.
•
To allow configuration accesses to the 41210, ground this
pin through a 2K Ω resistor.
A_TEST1,
A_TEST2,
B_TEST1,
B_TEST2
A_PME#,
B_PME#,
These signals REQUIRE an external pull-up, 8.2KΩ to
3.3V.
A_STRAP[3],
A_STRAP[4],
A_STRAP[5],
B_STRAP[3],
B_STRAP[4],
B_STRAP[5]
In normal operating mode, this
pin must be tied high.
NC17
This signal requires an external pull-up, 8.2KΩ to 3.3V.
Table 22. SMBus Interface Signals
Signal
Recommendations
Reason/Impact
SMBCLK
SMBDAT
Connect to VCC33 through an 8.2KΩ pullup resistor.
Connect to VCC33 through an 8.2KΩ pullup resistor.
SMBus addressing:
Bit 7----------------’1’
Bit 6----------------’1’
Bit 5---------------SMBUS[5]
Bit 4----------------’0’
SMBUS[5],
SMBUS[3:1]
Sampled on the rising edge of
PERST#.
Bit 3---------------SMBUS[3]
Bit 2---------------SMBUS[2]
Bit 1---------------SMBUS[1]
Use 8.2KΩ resistors as pullups to VCC33 for a ‘1’ and
as pulldowns to ground for a ‘0’ to set the SMBus
address.
62
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
Table 23. Power and Ground Signals
Signal
Recommendations
Reason/Impact
100Ω ±1% (1/4 W) pulldown resistor to ground.
Analog compensation pin for
PCI. 0.75V nominal.
RCOMP
The trace impedance of this signal should be < 0.1Ω.
Connect to 1.5V power supply.
Note: Linear voltage regulators are recommended
when using 1.5 Volt power supplies.
Decoupling:
VCC15
1.5V ±5% core voltage.
5 0.1uF caps beneath package (backside of board)
2 1.0 uF caps as close as design rules permit to
package
3 10 uF caps as close as design rules permit to
package
Connect to 3.3V power supply.
Decoupling: TBD
The platform must insure that the VCC33 voltage rail
be greater than to (or no less than 0.5V below) VCC15
(absolute voltage value at all times during 41210
Bridge operation, including during system power up,
power down or any other time during system operation.
This can be accomplished by placing a diode (with a
voltage drop < 0.5V) between VCC15 and VCC33.
Anode will be connected to VCC15 and cathode will be
connected to VCC33.
VCC33
3.3V ±5% PCI I/O voltage.
Connect to 1.5V power supply.
1.5V ±3% Analog PCI Express
voltage.
VCCAPE
VCCAPCI[2:0]
Analog PCI voltage pins.
Voltage output of the bandgap filter circuit into 41210
Bridge, separated from the rest of the VCC15s. See
Figure 25 for circuit.
VCCBGPE
VCCPE
2.5V ±3% PCI Express voltage.
Connect to 1.5V power supply.
Decoupling:
3 0.1uF caps beneath package (backside of board)
1.5V ±3% PCI Express voltage.
4 1.0 uF caps as close as design rules permit to
package
2 10 uF caps as close as design rules permit to
package
Ground reference for all
supplies.
VSS
Connect to ground.
VSSAPE
VSSBGPE
Analog ground for PCI Express.
Ground for the bandgap filter circuit, separated from
Ground for analog bandgap
voltage.
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
63
Download from Www.Somanuals.com. All Manuals Search And Download.
Design Guide Checklist
Table 24. JTAG Signals
Signal
Recommendations
Reason/Impact
Internal pull-up
TCK
TDI
If not used for JTAG, leave as No Connect
If not used for JTAG, leave as No Connect
If not used for JTAG, leave as No Connect
If not used for JTAG, leave as No Connect
Internal pull-up
Internal pull-up
Internal pull-up
TDO
TMS
If TAP interface is not used this
should be tied to ground.
TRST#
Connect to ground via a 1KΩ pulldown resistor.
64
Intel® 41210 Serial to Parallel PCI Bridge Design Guide
Download from Www.Somanuals.com. All Manuals Search And Download.
|