TI XIO2001

XIO2001 PCI Express™ to PCI Bus Translation Bridge
Data Manual
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Literature Number: SCPS212B
May 2009 – Revised July 2009
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
www.ti.com
Contents
1
Introduction ....................................................................................................................... 11
2
Overview ........................................................................................................................... 12
1.1
2.1
2.2
2.3
2.4
2.5
2.6
2.7
3
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
3.11
3.12
3.13
3.14
3.15
3.16
12
12
13
13
13
13
21
Power-Up/-Down Sequencing ............................................................................................
3.1.1
Power-Up Sequence ............................................................................................
3.1.2
Power-Down Sequence.........................................................................................
Bridge Reset Features .....................................................................................................
PCI Express Interface .....................................................................................................
3.3.1
External Reference Clock ......................................................................................
3.3.2
Beacon ............................................................................................................
3.3.3
Wake ..............................................................................................................
3.3.4
Initial Flow Control Credits .....................................................................................
3.3.5
PCI Express Message Transactions ..........................................................................
PCI Bus Interface...........................................................................................................
3.4.1
I/O Characteristics ...............................................................................................
3.4.2
Clamping Voltage ................................................................................................
3.4.3
PCI Bus Clock Run ..............................................................................................
3.4.4
PCI Bus External Arbiter........................................................................................
3.4.5
MSI Messages Generated from the Serial IRQ Interface ..................................................
3.4.6
PCI Bus Clocks ..................................................................................................
PCI Port Arbitration ........................................................................................................
3.5.1
Classic PCI Arbiter ..............................................................................................
Configuration Register Translation .......................................................................................
PCI Interrupt Conversion to PCI Express Messages ..................................................................
PME Conversion to PCI Express Messages ...........................................................................
PCI Express to PCI Bus Lock Conversion ..............................................................................
Two-Wire Serial-Bus Interface ............................................................................................
3.10.1 Serial-Bus Interface Implementation ..........................................................................
3.10.2 Serial-Bus Interface Protocol...................................................................................
3.10.3 Serial-Bus EEPROM Application ..............................................................................
3.10.4 Accessing Serial-Bus Devices Through Software ...........................................................
Advanced Error Reporting Registers ....................................................................................
Data Error Forwarding Capability ........................................................................................
General-Purpose I/O Interface............................................................................................
Set Slot Power Limit Functionality .......................................................................................
PCI Express and PCI Bus Power Management ........................................................................
Auto Pre-Fetch Agent ......................................................................................................
28
29
30
30
31
31
32
32
32
32
33
33
33
33
34
34
35
36
36
36
38
38
39
40
41
41
43
45
45
45
46
46
46
47
Classic PCI Configuration Space .......................................................................................... 48
4.1
4.2
4.3
4.4
2
Description ..................................................................................................................
Related Documents ........................................................................................................
Documents Conventions ..................................................................................................
Document History ..........................................................................................................
Ordering Information .......................................................................................................
Terminal Assignments .....................................................................................................
Terminal Descriptions ......................................................................................................
Feature/Protocol Descriptions.............................................................................................. 28
3.1
4
Features ..................................................................................................................... 11
Vendor ID Register .........................................................................................................
Device ID Register .........................................................................................................
Command Register ........................................................................................................
Status Register .............................................................................................................
Contents
49
49
50
51
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4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20
4.21
4.22
4.23
4.24
4.25
4.26
4.27
4.28
4.29
4.30
4.31
4.32
4.33
4.34
4.35
4.36
4.37
4.38
4.39
4.40
4.41
4.42
4.43
4.44
4.45
4.46
4.47
4.48
4.49
4.50
4.51
4.52
4.53
4.54
4.55
4.56
4.57
SCPS212B – MAY 2009 – REVISED JULY 2009
Class Code and Revision ID Register ...................................................................................
Cache Line Size Register .................................................................................................
Primary Latency Timer Register ..........................................................................................
Header Type Register .....................................................................................................
BIST Register ...............................................................................................................
Device Control Base Address Register .................................................................................
Primary Bus Number Register ............................................................................................
Secondary Bus Number Register ........................................................................................
Subordinate Bus Number Register ......................................................................................
Secondary Latency Timer Register ......................................................................................
I/O Base Register ..........................................................................................................
I/O Limit Register ...........................................................................................................
Secondary Status Register................................................................................................
Memory Base Register ....................................................................................................
Memory Limit Register .....................................................................................................
Prefetchable Memory Base Register ....................................................................................
Prefetchable Memory Limit Register .....................................................................................
Prefetchable Base Upper 32-Bit Register ...............................................................................
Prefetchable Limit Upper 32-Bit Register ...............................................................................
I/O Base Upper 16-Bit Register ..........................................................................................
I/O Limit Upper 16-Bit Register ...........................................................................................
Capabilities Pointer Register..............................................................................................
Interrupt Line Register .....................................................................................................
Interrupt Pin Register ......................................................................................................
Bridge Control Register....................................................................................................
Capability ID Register......................................................................................................
Next Item Pointer Register ................................................................................................
Subsystem Vendor ID Register...........................................................................................
Subsystem ID Register ....................................................................................................
Capability ID Register......................................................................................................
Next Item Pointer Register ................................................................................................
Power Management Capabilities Register ..............................................................................
Power Management Control/Status Register ...........................................................................
Power Management Bridge Support Extension Register .............................................................
Power Management Data Register ......................................................................................
MSI Capability ID Register ................................................................................................
Next Item Pointer Register ................................................................................................
MSI Message Control Register ...........................................................................................
MSI Message Lower Address Register .................................................................................
MSI Message Upper Address Register .................................................................................
MSI Message Data Register ..............................................................................................
PCI Express Capability ID Register ......................................................................................
Next Item Pointer Register ...............................................................................................
PCI Express Capabilities Register .......................................................................................
Device Capabilities Register ..............................................................................................
Device Control Register ...................................................................................................
Device Status Register ....................................................................................................
Link Capabilities Register .................................................................................................
Link Control Register ......................................................................................................
Link Status Register........................................................................................................
Serial-Bus Data Register ..................................................................................................
Serial-Bus Word Address Register.......................................................................................
Serial-Bus Slave Address Register .....................................................................................
Contents
52
52
53
53
53
53
54
54
54
55
55
55
56
57
57
57
58
58
59
59
59
60
60
60
61
63
63
63
64
64
64
64
65
66
66
66
67
67
67
68
68
69
69
69
70
71
72
72
73
74
75
75
75
3
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
4.58
4.59
4.60
4.61
4.62
4.63
4.64
4.65
4.66
4.67
4.68
4.69
4.70
4.71
4.72
4.73
4.74
4.75
4.76
4.77
4.78
5
76
77
77
78
79
79
80
81
83
84
85
86
87
88
88
89
91
92
93
94
94
Advanced Error Reporting Capability ID Register ..................................................................... 95
Next Capability Offset/Capability Version Register .................................................................... 96
Uncorrectable Error Status Register ..................................................................................... 96
Uncorrectable Error Mask Register ...................................................................................... 97
Uncorrectable Error Severity Register ................................................................................... 98
Correctable Error Status Register ........................................................................................ 99
Correctable Error Mask Register ....................................................................................... 100
Advanced Error Capabilities and Control Register ................................................................... 101
Header Log Register ..................................................................................................... 101
Secondary Uncorrectable Error Status Register ...................................................................... 102
Secondary Uncorrectable Error Mask Register ....................................................................... 103
Secondary Uncorrectable Error Severity .............................................................................. 104
Secondary Error Capabilities and Control Register .................................................................. 105
Secondary Header Log Register........................................................................................ 106
Memory-Mapped TI Proprietary Register Space .................................................................... 107
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
6.12
6.13
6.14
6.15
4
Serial-Bus Control and Status Register .................................................................................
GPIO Control Register .....................................................................................................
GPIO Data Register ........................................................................................................
TL Control and Diagnostic Register 0 ...................................................................................
Control and Diagnostic Register 1 .......................................................................................
Control and Diagnostic Register 2 .......................................................................................
Subsystem Access Register ..............................................................................................
General Control Register ..................................................................................................
Clock Control Register .....................................................................................................
Clock Mask Register .......................................................................................................
Clock Run Status Register ................................................................................................
Arbiter Control Register ...................................................................................................
Arbiter Request Mask Register ...........................................................................................
Arbiter Time-Out Status Register ........................................................................................
Serial IRQ Mode Control Register .......................................................................................
Serial IRQ Edge Control Register ........................................................................................
Serial IRQ Status Register ................................................................................................
Pre-Fetch Agent Request Limits Register ..............................................................................
Cache Timer Transfer Limit Register ....................................................................................
Cache Timer Lower Limit Register .......................................................................................
Cache Timer Upper Limit Register .......................................................................................
PCI Express Extended Configuration Space .......................................................................... 95
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
6
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Device Control Map ID Register ........................................................................................
Revision ID Register......................................................................................................
GPIO Control Register ...................................................................................................
GPIO Data Register ......................................................................................................
Serial-Bus Data Register ................................................................................................
Serial-Bus Word Address Register .....................................................................................
Serial-Bus Slave Address Register ....................................................................................
Serial-Bus Control and Status Register ................................................................................
Serial IRQ Mode Control Register ......................................................................................
Serial IRQ Edge Control Register ......................................................................................
Serial IRQ Status Register ..............................................................................................
Pre-Fetch Agent Request Limits Register .............................................................................
Cache Timer Transfer Limit Register...................................................................................
Cache Timer Lower Limit Register .....................................................................................
Cache Timer Upper Limit Register .....................................................................................
Contents
107
108
108
109
110
110
110
111
112
112
114
116
117
117
118
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7
Electrical Characteristics ................................................................................................... 119
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.10
7.11
8
9
SCPS212B – MAY 2009 – REVISED JULY 2009
Absolute Maximum Ratings .............................................................................................
Recommended Operating Conditions ..................................................................................
Nominal Power Consumption ...........................................................................................
PCI Express Differential Transmitter Output Ranges ................................................................
PCI Express Differential Receiver Input Ranges .....................................................................
PCI Express Differential Reference Clock Input Ranges ............................................................
PCI Bus Electrical Characteristics .....................................................................................
3.3-V I/O Electrical Characteristics ....................................................................................
PCI Bus Timing Requirements ..........................................................................................
ZGU Thermal Characteristics ...........................................................................................
Parameter Measurement Information ..................................................................................
119
119
120
120
121
122
123
123
124
124
125
Glossary .......................................................................................................................... 126
Mechanical Data ............................................................................................................... 128
Contents
5
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
www.ti.com
List of Figures
2-1
2-2
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18
7-1
7-2
7-3
7-4
6
..................................................................... 14
XIO2001 ZAJ MicroStar BGA Package (Bottom View) ...................................................................... 16
XIO2001 Block Diagram.......................................................................................................... 28
Power-Up Sequence .............................................................................................................. 29
Power-Down Sequence .......................................................................................................... 30
3-State Bidirectional Buffer ...................................................................................................... 33
Type 0 Configuration Transaction Address Phase Encoding ............................................................... 36
Type 1 Configuration Transaction Address Phase Encoding ............................................................... 37
PCI Express ASSERT_INTX Message......................................................................................... 38
PCI Express DEASSERT_INTX Message ..................................................................................... 38
PCI Express PME Message ..................................................................................................... 39
Starting a Locked Sequence..................................................................................................... 39
Continuing a Locked Sequence ................................................................................................. 40
Terminating a Locked Sequence................................................................................................ 40
Serial EEPROM Application ..................................................................................................... 41
Serial-Bus Start/Stop Conditions and Bit Transfers .......................................................................... 41
Serial-Bus Protocol Acknowledge............................................................................................... 42
Serial-Bus Protocol – Byte Write ................................................................................................ 42
Serial-Bus Protocol – Byte Read ................................................................................................ 43
Serial-Bus Protocol – Multibyte Read .......................................................................................... 43
Load Circuit And Voltage Waveforms ......................................................................................... 125
CLK Timing Waveform .......................................................................................................... 126
PRST Timing Waveforms....................................................................................................... 126
Shared Signals Timing Waveforms ........................................................................................... 126
XIO2001 ZGU MicroStar BGA Package (Bottom View)
List of Figures
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SCPS212B – MAY 2009 – REVISED JULY 2009
List of Tables
2-1
ZGU Terminals Sorted Alphanumerically ...................................................................................... 15
2-2
ZAJ Terminals Sorted Alphanumerically ....................................................................................... 17
2-3
XIO2001 Signal Names Sorted Alphabetically ................................................................................ 19
2-4
Power Supply Terminals ......................................................................................................... 21
2-5
Ground Terminals ................................................................................................................. 21
2-6
Combined Power Output Terminals ............................................................................................ 22
2-7
PCI Express Terminals ........................................................................................................... 22
2-8
PCI System Terminals ............................................................................................................ 23
2-9
JTAG Terminals ................................................................................................................... 25
2-10
Miscellaneous Terminals ......................................................................................................... 25
3-1
XIO2001 Reset Options .......................................................................................................... 30
3-2
Initial Flow Control Credit Advertisements ..................................................................................... 32
3-3
Messages Supported by the Bridge ............................................................................................ 32
3-4
IRQ Interrupt to MSI Message Mapping
3-5
.......................................................................................
Classic PCI Arbiter Registers ....................................................................................................
35
36
3-6
Type 0 Configuration Transaction
IDSEL Mapping .................................................................................................................... 37
3-7
Interrupt Mapping In The Code Field ........................................................................................... 38
3-8
EEPROM Register Loading Map................................................................................................ 43
3-9
Registers Used To Program Serial-Bus Devices ............................................................................. 45
3-10
Clocking In Low Power States................................................................................................... 47
4-1
Classic PCI Configuration Register Map ....................................................................................... 48
4-2
Command Register Description ................................................................................................. 50
4-3
Status Register Description ...................................................................................................... 51
4-4
Class Code and Revision ID Register Description
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
...........................................................................
Device Control Base Address Register Description ..........................................................................
I/O Base Register Description ...................................................................................................
I/O Limit Register Description ...................................................................................................
Secondary Status Register Description ........................................................................................
Memory Base Register Description .............................................................................................
Memory Limit Register Description .............................................................................................
Prefetchable Memory Base Register Description .............................................................................
Prefetchable Memory Limit Register Description .............................................................................
Prefetchable Base Upper 32-Bit Register Description .......................................................................
Prefetchable Limit Upper 32-Bit Register Description ........................................................................
I/O Base Upper 16-Bit Register Description ...................................................................................
I/O Limit Upper 16-Bit Register Description ...................................................................................
Bridge Control Register Description ............................................................................................
Power Management Capabilities Register Description ......................................................................
Power Management Control/Status Register Description ...................................................................
List of Tables
52
54
55
55
56
57
57
58
58
58
59
59
60
61
65
65
7
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
www.ti.com
4-20
PM Bridge Support Extension Register Description .......................................................................... 66
4-21
................................................................................... 67
MSI Message Lower Address Register Description .......................................................................... 68
MSI Message Data Register Description ...................................................................................... 68
PCI Express Capabilities Register Description ................................................................................ 69
Device Capabilities Register Description ...................................................................................... 70
Device Control Register Description ............................................................................................ 71
Device Status Register Description ............................................................................................. 72
Link Capabilities Register Description .......................................................................................... 73
Link Control Register Description ............................................................................................... 73
Link Status Register Description ................................................................................................ 74
Serial-Bus Slave Address Register Descriptions ............................................................................. 76
Serial-Bus Control and Status Register Description .......................................................................... 76
GPIO Control Register Description ............................................................................................. 77
GPIO Data Register Description ................................................................................................ 78
Control and Diagnostic Register 0 Description ............................................................................... 78
Control and Diagnostic Register 1 Description ............................................................................... 79
Control and Diagnostic Register 2 Description ............................................................................... 80
Subsystem Access Register Description....................................................................................... 80
General Control Register Description .......................................................................................... 81
Clock Control Register Description ............................................................................................. 83
Clock Mask Register Description ............................................................................................... 84
Clock Run Status Register Description ........................................................................................ 85
Clock Control Register Description ............................................................................................. 86
Arbiter Request Mask Register Description ................................................................................... 87
Arbiter Time-Out Status Register Description ................................................................................. 88
Serial IRQ Mode Control Register Description ................................................................................ 89
Serial IRQ Edge Control Register Description ................................................................................ 89
Serial IRQ Status Register Description ........................................................................................ 91
Pre-Fetch Agent Request Limits Register Description ....................................................................... 92
Cache Timer Transfer Limit Register Description............................................................................. 93
Cache Timer Lower Limit Register Description ............................................................................... 94
Cache Timer Upper Limit Register Description ............................................................................... 94
PCI Express Extended Configuration Register Map.......................................................................... 95
Uncorrectable Error Status Register Description ............................................................................. 96
Uncorrectable Error Mask Register Description............................................................................... 97
Uncorrectable Error Severity Register Description ........................................................................... 98
Correctable Error Status Register Description ................................................................................ 99
Correctable Error Mask Register Description ................................................................................ 100
Advanced Error Capabilities and Control Register Description............................................................ 101
Secondary Uncorrectable Error Status Register Description .............................................................. 102
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
4-34
4-35
4-36
4-37
4-38
4-39
4-40
4-41
4-42
4-43
4-44
4-45
4-46
4-47
4-48
4-49
4-50
4-51
4-52
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
8
MSI Message Control Register Description
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5-9
5-10
5-11
5-12
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
6-12
SCPS212B – MAY 2009 – REVISED JULY 2009
...............................................................
Secondary Uncorrectable Error Severity Register Description ...........................................................
Secondary Error Capabilities and Control Register Description ...........................................................
Secondary Header Log Register Description ................................................................................
Device Control Memory Window Register Map .............................................................................
GPIO Control Register Description ............................................................................................
GPIO Data Register Description ...............................................................................................
Serial-Bus Slave Address Register Descriptions ............................................................................
Serial-Bus Control and Status Register Description ........................................................................
Serial IRQ Mode Control Register Description ..............................................................................
Serial IRQ Edge Control Register Description ...............................................................................
Serial IRQ Status Register Description .......................................................................................
Pre-Fetch Agent Request Limits Register Description......................................................................
Cache Timer Transfer Limit Register Description ...........................................................................
Cache Timer Lower Limit Register Description ..............................................................................
Cache Timer Upper Limit Register Description ..............................................................................
Secondary Uncorrectable Error Mask Register Description
103
104
105
106
107
108
109
110
111
112
113
114
116
117
118
118
MicroStar is a trademark of Texas Instruments.
PCI Express is a trademark of PCI-SIG.
All other trademarks are the property of their respective owners.
List of Tables
9
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
10
List of Tables
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1
Introduction
1.1
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Full ×1 PCI Express Throughput
Fully Compliant with PCI Express to PCI/PCI-X
Bridge Specification, Revision 1.0
Fully Compliant with PCI Express Base
Specification, Revision 2.0
Fully Compliant with PCI Local Bus
Specification, Revision 2.3
PCI Express Advanced Error Reporting
Capability Including ECRC Support
Support for D1, D2, D3hot, and D3cold
Active-State Link Power Management Saves
Power When Packet Activity on the PCI
Express Link is Idle, Using Both L0s and L1
States
Wake Event and Beacon Support
Error Forwarding Including PCI Express Data
Poisoning and PCI Bus Parity Errors
Utilizes 100-MHz Differential PCI Express
Common Reference Clock or 125-MHz
Single-Ended, Reference Clock
Optional Spread Spectrum Reference Clock is
Supported
Robust Pipeline Architecture To Minimize
Transaction Latency
Full PCI Local Bus 66-MHz/32-Bit Throughput
Support for Six Subordinate PCI Bus Masters
with Internal Configurable, 2-Level
SCPS212B – MAY 2009 – REVISED JULY 2009
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Prioritization Scheme
Two Package Options: 12 mm × 12 mm and 7
mm × 7 mm
Internal PCI Arbiter Supporting Up to 6
External PCI Masters
Advanced PCI Express Message Signaled
Interrupt Generation for Serial IRQ Interrupts
External PCI Bus Arbiter Option
PCI Bus LOCK Support
JTAG/BS for Production Test
PCI-Express CLKREQ Support
Clock Run and Power Override Support
Six Buffered PCI Clock Outputs (25 MHz, 33
MHz, 50 MHz, or 66 MHz)
PCI Bus Interface 3.3-V and 5.0-V (25 MHz or
33 MHz only at 5.0 V) Tolerance Options
Integrated AUX Power Switch Drains VAUX
Power Only When Main Power Is Off
Five 3.3-V, Multifunction, General-Purpose I/O
Terminals
Memory-Mapped EEPROM Serial-Bus
Controller Supporting PCI Express Power
Budget/Limit Extensions for Add-In Cards
Compact Footprint, Lead-Free 144-Ball, ZAJ
MicroStar™ BGA or Lead-Free 169-Ball ZGU
MicroStar BGA
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this document.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009–2009, Texas Instruments Incorporated
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
2
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Overview
The Texas Instruments XIO2001 is a PCI Express to PCI local bus translation bridge that provides full PCI
Express and PCI local bus functionality and performance.
2.1
Description
The XIO2001 is a single-function PCI Express to PCI translation bridge that is fully compliant to the PCI
Express to PCI/PCI-X Bridge Specification, Revision 1.0. For downstream traffic, the bridge
simultaneously supports up to eight posted and four non-posted transactions. For upstream traffic, up to
six posted and and four non-posted transactions are simultaneously supported.
The PCI Express interface is fully compliant to the PCI Express Base Specification, Revision 2.0.
The PCI Express interface supports a ×1 link operating at full 250 MB/s packet throughput in each
direction simultaneously. Also, the bridge supports the advanced error reporting including extended CRC
(ECRC) as defined in the PCI Express Base Specification. Supplemental firmware or software is required
to fully utilize both of these features.
Robust pipeline architecture is implemented to minimize system latency across the bridge. If parity errors
are detected, then packet poisoning is supported for both upstream and downstream operations.
The PCI local bus is fully compliant with the PCI Local Bus Specification (Revision 2.3) and associated
programming model. Also, the bridge supports the standard PCI-to-PCI bridge programming model. The
PCI bus interface is 32-bit and can operate at either 25 MHz, 33 MHz, 50 MHz, or 66 MHz. Also, the PCI
interface provides fair arbitration and buffered clock outputs for up to 6 subordinate devices.
Power management (PM) features include active state link PM, PME mechanisms, the beacon and wake
protocols, and all conventional PCI D-states. If the active state link PM is enabled, then the link
automatically saves power when idle using the L0s and L1 states. PM active state NAK, PM PME, and
PME-to-ACK messages are supported. Standard PCI bus power management features provide several
low power modes, which enable the host system to further reduce power consumption.
The bridge has additional capabilities including, but not limited to, serial IRQ with MSI messages, serial
EEPROM, power override, clock run, PCI Express clock request and PCI bus LOCK. Also, five
general-purpose inputs and outputs (GPIOs) are provided for further system control and customization.
2.2
Related Documents
•
•
•
•
•
•
•
•
12
PCI Express to PCI/PCI-X Bridge Specification, Revision 1.0
PCI Express Base Specification, Revision 2.0
PCI Express Card Electromechanical Specification, Revision 2.0
PCI Local Bus Specification, Revision 2.3
PCI-to-PCI Bridge Architecture Specification, Revision 1.2
PCI Bus Power Management Interface Specification, Revision 1.2
PCI Mobile Design Guide, Revision 1.1
Serialized IRQ Support for PCI Systems, Revision 6.0
Overview
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2.3
SCPS212B – MAY 2009 – REVISED JULY 2009
Documents Conventions
Throughout this data manual, several conventions are used to convey information. These conventions are
listed below:
1. To identify a binary number or field, a lower case b follows the numbers. For example: 000b is a 3-bit
binary field.
2. To identify a hexadecimal number or field, a lower case h follows the numbers. For example: 8AFh is a
12-bit hexadecimal field.
3. All other numbers that appear in this document that do not have either a b or h following the number
are assumed to be decimal format.
4. If the signal or terminal name has a bar above the name (for example, GRST), then this indicates the
logical NOT function. When asserted, this signal is a logic low, 0, or 0b.
5. Differential signal names end with P, N, +, or – designators. The P or + designators signify the positive
signal associated with the differential pair. The N or – designators signify the negative signal
associated with the differential pair.
6. RSVD indicates that the referenced item is reserved.
7. In Sections 4 through 6, the configuration space for the bridge is defined. For each register bit, the
software access method is identified in an access column. The legend for this access column includes
the following entries:
– r – read access by software
– u – updates by the bridge internal hardware
– w – write access by software
– c – clear an asserted bit with a write-back of 1b by software. Write of zero to the field has no effect
– s – the field may be set by a write of one. Write of zero to the field has no effect
– na – not accessible or not applicable
2.4
Document History
REVISION
DATE
REVISION
NUMBER
5/2009
–
Initial release
5/2009
A
Corrected typos in Table 2-1 and Table 2-2
2.5
REVISION COMMENTS
Ordering Information
ORDERING
NUMBER
NAME
VOLTAGE
PACKAGE
XIO2001
PCI-Express to PCI Bridge
3.3-V and 5.0-V tolerant PCI bus I/Os
with 3.3-V and 1.5-V power terminals
169-terminal ZGU (Lead-Free) Microstar
PBGA
XIO2001
PCI-Express to PCI Bridge
3.3-V and 5.0-V tolerant PCI bus I/Os
with 3.3-V and 1.5-V power terminals
144-terminal ZAJ (Lead-Free) MicroStar
PBGA
2.6
Terminal Assignments
The XIO2001 is available in either a 169-ball ZGU MicroStar BGA or a 144–ball ZAJ MicroStar BGA
package.
Figure 2-1 shows a terminal diagram of the ZGU package, and Table 2-1 lists the ZGU terminals sorted
alphanumerically.
Figure 2-2 shows a terminal diagram of the ZAJ package, and Table 2-2 lists the ZAJ package terminals
sorted alphanumerically.
Table 2-3 shows the terminals by the alphabetically sorted signal names for both packages.
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1
2
3
4
N
C/BE[3]
AD25
AD27
AD30
M
AD20
AD22
AD24
AD26
L
AD18
AD19
AD21
K
AD16
AD17
J
IRDY
H
TRDY
5
AD31
6
7
8
9
10
11
12
13
GPIO0//
CLKRUN
GPIO2
GPIO3//SDA
JTAG_TDI
GRST
N
GPIO1//
PWR_OVRD
GPIO4//
SCL
JTAG_TDO
JTAG_TCK
WAKE
M
VSS
PME
VDD_15_
COMB
L
REF1_PCIE
K
INTB
PRST
SERIRQ
AD28
INTA
INTC
LOCK
AD23
AD29
M66EN
INTD
VDD_33
PCIR
VSS
VSS
VSS
VDD_15
VSS
VDD_33
VSSA
VDD_33_
COMB_IO
REF0_PCIE
FRAME
C/BE[2]
VDD_33
VSS
VSS
VSS
VSS
VSS
VSS
VDD_33_
AUX
VDD_33
VDD_33_
COMB
J
DEVSEL
VDD_33
VSS
VSS
VSS
VSS
VSS
VSS
VDD_15
PERST
VSSA
VDDA_15
H
JTAG_
TRST#
JTAG_TMS
G
STOP
PERR
SERR#
VDD_15
VSS
VSS
VSS
VSS
VSS
VDD_15
VSSA
TXN
TXP
G
F
PAR
C/BE[1]
CLK
VSS
VSS
VSS
VSS
VSS
VSS
VDD_15
VSS
VSS
VDDA_15
F
E
AD15
AD14
AD13
VDD_33
VSS
VSS
VSS
VSS
VSS
VSSA
VSSA
RXN
RXP
E
D
AD12
AD11
AD8
VSS
VDD_33
VSS
VDD_15
VSS
VDD_33
VSS
CLKREQ
VREG_PD33
VDDA_33
D
VSSA
REFCLK–
REFCLK+
C
C
AD10
AD9
AD7
AD5
AD0
GNT1
VDD_33
REQ3
REQ4
EXT_ARB_EN
B
C/BE[0]
AD6
AD3
AD2
CLKOUT0
CLKOUT1
CLKOUT3
GNT2
GNT3
GNT5
A
PCIR
AD4
AD1
REQ0
GNT0
REQ1
CLKOUT2
REQ2
1
2
3
5
6
7
4
8
CLKOUT6
PCLK66_SEL REFCLK125
_SEL
CLKOUT4
CLKOUT5
GNT4
REQ5
CLKRUN_EN
9
10
11
12
13
B
A
Figure 2-1. XIO2001 ZGU MicroStar BGA Package (Bottom View)
14
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Table 2-1. ZGU Terminals Sorted Alphanumerically
BALL
SIGNAL NAME
BALL
SIGNAL NAME
BALL
SIGNAL NAME
A01
PCIR
D06
VSS
G11
VSSA
A02
AD4
D07
VDD_15
G12
TXN
A03
AD1
D08
VSS
G13
TXP
A04
REQ0
D09
VDD_33
H01
TRDY
A05
GNT0
D10
VSS
H02
DEVSEL
A06
REQ1
D11
CLKREQ
H03
VDD_33
A07
CLKOUT2
D12
VREG_PD33
H04
VSS
A08
REQ2
D13
VDDA_33
H05
VSS
A09
CLKOUT4
E01
AD15
H06
VSS
A10
CLKOUT5
E02
AD14
H07
VSS
A11
GNT4
E03
AD13
H08
VSS
A12
REQ5
E04
VDD_33
H09
VSS
A13
CLKRUN_EN
E05
VSS
H10
VDD_15
B01
C/BE[0]
E06
VSS
H11
PERST
B02
AD6
E07
VSS
H12
VSSA
B03
AD3
E08
VSS
H13
VDDA_15
B04
AD2
E09
VSS
J01
IRDY
B05
CLKOUT0
E10
VSSA
J02
FRAME
B06
CLKOUT1
E11
VSSA
J03
C/BE[2]
B07
CLKOUT3
E12
RXN
J04
VDD_33
B08
GNT2
E13
RXP
J05
VSS
B09
GNT3
F01
PAR
J06
VSS
B10
GNT5
F02
C/BE[1]
J07
VSS
B11
CLKOUT6
F03
CLK
J08
VSS
B12
PCLK66_SEL
F04
VSS
J09
VSS
B13
RECLK125_SEL
F05
VSS
J10
VSS
C01
AD10
F06
VSS
J11
VDD_33_AUX
C02
AD9
F07
VSS
J12
VDD_33
C03
A7
F08
VSS
J13
VDD_33_COMB
C04
A5
F09
VSS
K01
AD16
C05
A0
F10
VDD_15
K02
AD17
C06
GNT1
F11
VSS
K03
PCIR
C07
VDD_33
F12
VSS
K04
VSS
C08
REQ3
F13
VDD_15
K05
VSS
C09
REQ4
G01
STOP
K06
VSS
C10
EXT_ARB_EN
G02
PERR
K07
VDD_15
C11
VSSA
G03
SERR
K08
VSS
C12
REFCLK–
G04
VDD_15
K09
VDD_33
C13
REFCLK+
G05
VSS
K10
VSSA
D01
AD12
G06
VSS
K11
VDD_33_COMB_IO
D02
AD11
G07
VSS
K12
REF0_PCIE
D03
AD8
G08
VSS
K13
REF1_PCIE
D04
VSS
G09
VSS
L01
AD18
D05
VDD_33
G10
VDD_15
L02
AD19
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Table 2-1. ZGU Terminals Sorted Alphanumerically (continued)
BALL
SIGNAL NAME
BALL
SIGNAL NAME
BALL
SIGNAL NAME
L03
AD21
M03
AD24
N03
AD27
L04
AD23
M04
AD26
N04
AD30
L05
AD29
M05
AD28
N05
AD31
L06
M66EN
M06
INTA
N06
INTB
L07
INTD
M07
INTC
N07
PRST
L08
VDD_33
M08
LOCK
N08
SERIRQ
L09
JTAG_TRST
M09
GPIO // PWR_OVRD
N09
GPIO0 // CLKRUN
L10
JTAG_TMS
M10
GPIO4 // SCL
N10
GPIO2
L11
VSS
M11
JTAG_TD0
N11
GPIO3 // SDA
L12
PME
M12
JTAG_TCK
N12
JTAG_TDI
L13
VDD_15_COMB
M13
WAKE
N13
GRST
M01
AD20
N01
C/BE[3]
M02
AD22
N02
AD25
1
2
3
4
N
AD21
AD24
AD27
AD28
M
AD18
AD22
C/BE[3]
L
AD16
AD20
AD23
K
C/BE[2]
AD19
J
FRAME
H
STOP
G
5
6
7
8
9
10
11
12
AD31
INTA
INTD
LOCK
GPIO0//
CLKRUN
GPIO2
JTAG_TDO
JTAG_TCK
AD25
AD29
M66EN
INTC
SERIRQ
GPIO1//
PWR_OVRD
GPIO4_
SCL
GRST
AD26
AD30
INTB
PRST
GPIO3//SDA
JTAG_
TRST
JTAG_TDI
JTAG_TMS
AD17
13
VDD_15_
COMB
N
PME
REF0_PCIE
M
WAKE
REF1_PCIE
L
VDD_33_
COMB_IO
VDD_33_
COMB
VDD_15
K
PCIR
VSS
VSS
VDD_15
VDD_15
VSS
VDD_33
VDD_33_
AUX
VSSA
J
DEVSEL
IRDY
VSS
VDD_33
VDD_33
VDD_15
VSS
PERST
VDDA_15
TXP
H
PAR
SERR
PERR
VSS
VDD_33
VDD_33
VDD_15
VSSA
VDD_15
VSSA
TXN
G
F
CLK
AD15
C/BE[1]
VSS
VDD_33
VDD_33
VDD_33
VSS
VDD_15
VSS
VSSA
F
E
AD13
AD12
AD14
VDD_33
VSS
VSS
VSS
VREG_PD33
VDDA_15
RXP
E
D
AD11
AD9
PCIR
CLKREQ
VSSA
RXN
D
C
AD10
C/BE[0]
AD5
AD2
AD1
REQ1
REQ2
REQ3
REQ5
CLKOUT6
CLKRUN_EN
VDDA_33
REFCLK+
C
B
AD8
AD6
AD0
CLKOUT0
CLKOUT1
CLKOUT2
GNT2
GNT3
GNT4
VSSA
REFCLK-
B
A
AD7
AD4
AD3
REQ0
REQ4
CLKOUT5
PCLK66_
SEL
EXT_ARB_
EN
REFCLK125
_SEL
A
1
2
3
10
11
12
13
TRDY
4
VSS
GNT0
GNT1
CLKOUT3
CLKOUT4
5
6
7
8
9
GNT5
Figure 2-2. XIO2001 ZAJ MicroStar BGA Package (Bottom View)
16
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Table 2-2. ZAJ Terminals Sorted Alphanumerically
BALL
SIGNAL NAME
BALL
SIGNAL NAME
BALL
SIGNAL NAME
A01
AD7
D06
No ball
G11
VDD_15
A02
AD4
D07
No ball
G12
VSSA
A03
AD3
D08
No ball
G13
TXN
A04
REQ0
D09
No ball
H01
STOP
A05
GNT0
D10
No ball
H02
DEVSEL
A06
GNT1
D11
CLKREQ
H03
IRDY
A07
CLKOUT3
D12
VSSA
H04
No ball
A08
CLKOUT4
D13
RXN
H05
VSS
A09
REQ4
E01
AD13
H06
VDD_33
A10
CLKOUT5
E02
AD12
H07
VDD_33
A11
PCLK66_SEL
E03
AD14
H08
VDD_15
A12
EXT_ARB_EN
E04
No ball
H09
VSS
A13
REFCLK125_SEL
E05
VDD_33
H10
No ball
B01
AD8
E06
VSS
H11
PERST
B02
No ball
E07
VSS
H12
VDDA_15
B03
AD6
E08
VSS
H13
TXP
B04
AD0
E09
VSS
J01
FRAME
B05
CLKOUT0
E10
No ball
J02
TRDY
B06
CLKOUT1
E11
VREG_PD33
J03
PCIR
B07
CLKOUT2
E12
VDD_15
J04
No ball
B08
GNT2
E13
RXP
J05
VSS
B09
GNT3
F01
CLK
J06
VSS
B10
GNT4
F02
AD15
J07
VDD_15
B11
GNT5
F03
C/BE[1]
J08
VDD_15
B12
VSSA
F04
No ball
J09
VSS
B13
REFCLK–
F05
VSS
J10
No ball
C01
AD10
F06
VDD_33
J11
VDD_33
C02
C/BE[0]
F07
VDD_33
J12
VDD_33_AUX
C03
AD5
F08
VDD_33
J13
VSSA
C04
AD2
F09
VSS
K01
C/BE[2]
C05
AD1
F10
No ball
K02
AD19
C06
REQ1
F11
VDD_15
K03
AD17
C07
REQ2
F12
VSS
K04
No ball
C08
REQ3
F13
VSSA
K05
No ball
C09
REQ5
G01
PAR
K06
No ball
C10
CLKOUT6
G02
SERR
K07
No ball
C11
CLKRUN_EN
G03
PERR
K08
No ball
C12
VDDA_33
G04
No ball
K09
No ball
C13
REFCLK+
G05
VSS
K10
No ball
D01
AD11
G06
VDD_33
K11
VDD_33_COMB_IO
D02
AD9
G07
VDD_33
K12
VDD_33_COMB
D03
PCIR
G08
VDD_15
K13
VDD_15
D04
No ball
G09
VSSA
L01
AD16
D05
No ball
G10
No ball
L02
AD20
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Table 2-2. ZAJ Terminals Sorted Alphanumerically (continued)
BALL
18
SIGNAL NAME
BALL
SIGNAL NAME
BALL
SIGNAL NAME
L03
AD23
M03
C/BE[3]
N03
AD27
L04
AD26
M04
AD25
N04
AD28
L05
AD30
M05
AD29
N05
AD31
L06
INTB
M06
M66EN
N06
INTA
L07
PRST
M07
INTC
N07
INTD
L08
GPIO3 // SDA
M08
SERIRQ
N08
LOCK
L09
JTAG_TRST
M09
GPIO // PWR_OVRD
N09
GPIO0 // CLKRUN
L10
JTAG_TD1
M10
GPIO4 // SCL
N10
GPIO2
L11
JTAG_TMS
M11
GRST
N11
JTAG_TDO
L12
WAKE
M12
PME
N12
JTAG_TCK
L13
REF1_PCIE
M13
REF0_PCIE
N13
VDD_15_COMB_IO
M01
AD18
N01
AD21
M02
AD22
N02
AD24
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Table 2-3. XIO2001 Signal Names Sorted Alphabetically
ZGU BALL #
ZAJ BALL #
AD0
SIGNAL NAME
C05
B04
CLKOUT5
SIGNAL NAME
ZGU BALL #
ZAJ BALL #
A10
A10
AD1
A03
C05
AD2
B04
C04
CLKOUT6
B11
C10
CLKREQ
D11
AD3
B03
D11
A03
CLKRUN_EN
A13
C11
AD4
A02
A02
DEVSEL
H02
H02
AD5
C04
C03
EXT_ARB_EN
C10
A12
AD6
B02
B03
FRAME
J02
J01
AD7
C03
A01
GNT0
A05
A05
AD8
D03
B01
GNT1
C06
A06
AD9
C02
D02
GNT2
B08
B08
AD10
C01
C01
GNT3
B09
B09
AD11
D02
D01
GNT4
A11
B10
AD12
D01
E02
GNT5
B10
B11
AD13
E03
E01
GPIO0 // CLKRUN
N09
N09
AD14
E02
E03
GPIO1 // PWR_OVRD
M09
M09
AD15
E01
F02
GPIO2
N10
N10
AD16
K01
L01
GPIO3 // SDA
N11
L08
AD17
K02
K03
GPIO4 // SCL
M10
M10
AD18
L01
M01
GRST
N13
M11
AD19
L02
K02
INTA
M06
N06
AD20
M01
L02
INTB
N06
L06
AD21
L03
N01
INTC
M07
M07
AD22
M02
M02
INTD
L07
N07
AD23
L04
L03
IRDY
J01
H03
AD24
M03
N02
JTAG_TCK
M12
N12
AD25
N02
M04
JTAG_TDI
N12
L10
AD26
M04
L04
JTAG_TDO
M11
N11
AD27
N03
N03
JTAG_TMS
L10
L11
AD28
M05
N04
JTAG–TRST
L09
L09
AD29
L05
M05
LOCK
M08
N08
AD30
N04
L05
M66EN
L06
M06
AD31
N05
N05
PAR
F01
G01
C/BE[0]
B01
C02
PCLK66_SEL
B12
A11
C/BE[1]
F02
F03
PCIR
A01
D03
C/BE[2]
J03
K01
K03
J03
C/BE[3]
N01
M03
PERR
G02
G03
CLK
F03
F01
PERST
H11
H11
CLKOUT0
B05
B05
PME
L12
M12
CLKOUT1
B06
B06
PRST
N07
L07
CLKOUT2
A07
B07
REF0_PCIE
K12
M13
CLKOUT3
B07
A07
REF1_PCIE
K13
L13
CLKOUT4
A09
A08
REFCLK–
C12
B13
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Table 2-3. XIO2001 Signal Names Sorted Alphabetically (continued)
ZGU BALL #
ZAJ BALL #
REFCLK+
SIGNAL NAME
C13
C13
RECLK125_SEL
B13
REQ0
REQ1
SIGNAL NAME
ZGU BALL #
ZAJ BALL #
K05
J05
A13
K06
J06
A04
A04
K08
J09
A06
C06
L11
H09
REQ2
A08
C07
J10
E09
REQ3
C08
C08
D10
E08
REQ4
C09
A09
D08
E07
REQ5
A12
C09
D06
F12
RXN
E12
D13
E05
F09
VSS
RXP
E13
E13
E06
SERIRQ
N08
M08
E07
SERR
G03
G02
E08
STOP
G01
H01
E09
TRDY
H01
J02
F05
TXN
G12
G13
F06
TXP
G13
H13
F07
VDD_15
G04
J08
F08
K07
H08
F09
D07
J07
G05
VDD_33
L13
G08
G06
H10
N13
G07
G10
K13
G08
F10
G11
G09
F11
H05
E04
E05
H06
H03
G06
H07
J04
H07
H08
L08
G07
H09
K09
H06
J05
D09
F08
J06
C07
F07
J07
D05
F06
J08
J12
J11
J09
VDD_33_AUX
J11
J12
F12
VDD_33_COMB
J13
K12
F11
VDD_33_COMBIO
K11
K11
K10
G09
VDDA_15
F13
E12
C11
B12
H13
H12
H12
J13
VDDA_33
D13
C12
G11
G12
VREG_PD33
D12
E11
E11
F13
VSS
D04
E06
E10
D12
F04
F05
M13
L12
K04
H05
20
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VSSA
WAKE
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2.7
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Terminal Descriptions
The following tables give a description of the terminals. These terminals are grouped in tables by
functionality. Each table includes the terminal name, terminal number, I/O type, and terminal description.
The following list describes the different input/output cell types that appear in the terminal description
tables:
• HS DIFF IN = High speed differential input
• HS DIFF OUT = High speed differential output
• PCI BUS = PCI bus 3-state bidirectional buffer with 3.3-V or 5.0-V clamp rail.
• LV CMOS = 3.3-V low voltage CMOS input or output with 3.3-V clamp rail
• BIAS = Input/output terminals that generate a bias voltage to determine a driver's operating current
• Feed through = these terminals connect directly to macros within the part and not through an input or
output cell.
• PWR = Power terminal
• GND = Ground terminal
Table 2-4. Power Supply Terminals
ZGU BALL #
ZAJ BALL #
I/O
TYPE
PCIR
A01, K03
D03, J03
I/O
VDD_15
G04, K07,
D07, L13,
H10, G10,
F10
J08, H08, J07,
G08, N13,
K13, G11, F11
VDDA_15
F13, H13
VDD_33
SIGNAL
EXTERNAL
PARTS
DESCRIPTION
Resistor
PCI Rail. 5.0-V or 3.3-V PCI bus clamp voltage to set
maximum I/O voltage tolerance of the secondary PCI bus
signals. Connect this terminal to the secondary PCI bus I/O
clamp rail through a 1kΩ resistor.
PWR
Bypass
capacitors
1.5-V digital core power terminals
E12, H12
PWR
Pi filter
1.5-V analog power terminal
E04, H03,
J04, L08,
K09, D09,
C07, D05,
J12
E05, G06,
H07, G07,
H06, F08, F07,
F06, J11
PWR
Bypass
capacitors
3.3-V digital I/O power terminal
VDD_33_AUX
J11
J12
PWR
Bypass
capacitors
3.3-V auxiliary power terminal Note: This terminal is
connected to VSS through a pulldown resistor if no auxiliary
supply is present.
VDDA_33
D13
C12
PWR
Pi filter
3.3-V analog power terminal
Table 2-5. Ground Terminals
SIGNAL
ZGU BALL #
ZAJ BALL #
I/O TYPE
VSS
D04, F04, H04,
K04, K05, K06,
K08, L11, J10,
D10, D08, D06,
F11, F12
E06, F05, G05, H05,
J05, J06, J09, H09,
E09, E08, E07, F12
,F09
GND
Digital ground terminals
VSS
E05, E06, E07,
E08, E09, F05,
F06, F07, F08,
F09, G05, G06,
G07, G08, G09,
H05, H06, H07,
H08, H09, J05,
J06, J07, J08,
J09
GND
Ground terminals for thermally-enhanced package
VSSA
K10, C11, H12,
G11, E11, E10
GND
Analog ground terminal
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G09, B12, J13, G12,
F13, D12
DESCRIPTION
Overview
21
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
www.ti.com
Table 2-6. Combined Power Output Terminals
SIGNAL
ZGU BALL #
ZAJ BALL #
L13
N13
VDD_15_COMB
I/O
TYPE
Feed
through
EXTERNAL
PARTS
Bypass
capacitors
DESCRIPTION
Internally-combined 1.5-V main and VAUX power output for
external bypass capacitor filtering. Supplies all internal 1.5-V
circuitry powered by VAUX.
Caution: Do not use this terminal to supply external power
to other devices.
VDD_33_COMB
J13
K12
Feed
through
Bypass
capacitors
Internally-combined 3.3-V main and VAUX power output for
external bypass capacitor filtering. Supplies all internal 3.3-V
circuitry powered by VAUX.
Caution: Do not use this terminal to supply external power
to other devices.
VDD_33_COMBIO
K11
K11
Feed
through
Bypass
capacitors
Internally-combined 3.3-V main and VAUX power output for
external bypass capacitor filtering. Supplies all internal 3.3-V
input/output circuitry powered by VAUX.
Caution: Do not use this terminal to supply external power
to other devices.
Table 2-7. PCI Express Terminals
SIGNAL
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
D11
D11
0
LV
CMOS
VDD_33_
CLKREQ
EXTERNAL
PARTS
DESCRIPTION
Clock request. When asserted low, requests
upstream device start clock in cases where
clock may be removed in L1.
COMBIO
–
Note: Since CLKREQ is an open-drain output
buffer, a system side pullup resistor is
required.
PERST
H11
H11
I
LV
CMOS
VDD_33_
COMBIO
–
PCI Express reset input. The PERST signal
identifies when the system power is stable and
generates an internal power on reset.
Note: The PERST input buffer has hysteresis.
REFCLK12
5_SEL
B13
A13
I
LV
CMOS
VDD_33
Reference clock select. This terminal selects
the reference clock input.
Pullup or
pulldown
resistor
0 = 100-MHz differential common reference
clock used.
1 = 125-MHz single-ended, reference clock
used.
REFCLK+
REFCLK–
REF0_PCIE
REF1_PCIE
C13
C12
K12
K13
C13
B13
M13
L13
DI
DI
I/O
HS DIFF
IN
VDD_33
HS DIFF
IN
VDD_33
BIAS
–
–
Reference clock. REFCLK+ and REFCLK–
comprise the differential input pair for the
100-MHz system reference clock. For a
single-ended, 125-MHz system reference
clock, use the REFCLK+ input.
Capacitor
for VSS for
singleended node
Reference clock. REFCLK+ and REFCLK–
comprise the differential input pair for the
100-MHz system reference clock. For a
single-ended, 125-MHz system reference
clock, attach a capacitor from REFCLK– to
VSS.
External
resistor
RXP
RXN
22
E13
E12
Overview
E13
D13
DI
HS DIFF
IN
VSS
–
External reference resistor + and – terminals
for setting TX driver current. An external
resistance of 14,532-Ω is connected between
REF0_PCIE and REF1_PCIE terminals. To
eliminate the need for a custom resistor, two
series resistors are recommended: a 14.3-kΩ,
1% resistor and a 232-Ω, 1% resistor.
High-speed receive pair. RXP and RXN
comprise the differential receive pair for the
single PCI Express lane supported.
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SCPS212B – MAY 2009 – REVISED JULY 2009
Table 2-7. PCI Express Terminals (continued)
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
TXP
TXN
G13
G12
H13
G13
DO
HS DIFF
OUT
VDD_15
WAKE
M13
L12
O
LV
CMOS
VDD_33_
SIGNAL
EXTERNAL
PARTS
Series
capacitor
DESCRIPTION
High-speed transmit pair. TXP and TXN
comprise the differential transmit pair for the
single PCI Express lane supported.
Wake is an active low signal that is driven low
to reactivate the PCI Express link hierarchy’s
main power rails and reference clocks.
COMBIO
–
Note: Since WAKE is an open-drain output
buffer, a system side pullup resistor is
required.
Table 2-8. PCI System Terminals
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
AD31
AD30
AD29
AD28
AD27
AD26
AD25
AD24
AD23
AD22
AD21
AD20
AD19
AD18
AD17
AD16
AD15
AD14
AD13
AD12
AD11
AD10
AD9
AD8
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
N05
N04
L05
M05
N03
M04
N02
M03
L04
M02
L03
M01
L02
L01
K02
K01
E01
E02
E03
D01
D02
C01
C02
D03
C03
B02
C04
A02
B03
B04
A03
C05
N05
L05
M05
N04
N03
L04
M04
N02
L03
M02
N01
L02
K02
M01
K03
L01
F02
E03
E01
E02
D01
C01
D02
B01
A01
B03
C03
A02
A03
C04
C05
B04
I/O
PCI Bus
PCIR
C/BE[3]
C/BE[2]
C/BE[1]
C/BE[0]
N01
J03
F02
B01
M03
K01
F03
C02
I/O
CLK
F03
F01
I
PCI Bus
PCIR
CLKOUT0
CLKOUT1
CLKOUT2
CLKOUT3
CLKOUT4
CLKOUT5
CLKOUT6
B05
B06
A07
B07
A09
A10
B11
B05
B06
B07
A07
A08
A10
C10
O
PCI Bus
PCIR
DEVSEL
H02
H02
I/O
SIGNAL
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EXTERNAL
PARTS
DESCRIPTION
PCI address data lines
–
PCI Bus
PCIR
PCI command byte enables
–
–
–
PCI Bus
PCIR
PCI clock input. This is the clock input to the
PCI bus core.
PCI clock outputs. These clock outputs are
used to clock the PCI bus. If the bridge PCI
bus clock outputs are used, then CLKOUT6
must be connected to the CLK input.
Pullup
PCI device select
resistor per
PCI spec
Overview
23
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
www.ti.com
Table 2-8. PCI System Terminals (continued)
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
FRAME
J02
J01
I/O
PCI Bus
PCIR
GNT5
GNT4
GNT3
GNT2
GNT1
GNT0
B10
A11
B09
B08
C06
A05
B11
B10
B09
B08
A06
A05
O
PCI Bus
PCIR
INTA
INTB
INTC
INTD
M06
N06
M07
L07
N06
L06
M07
N07
I
PCI Bus
PCIR
PCI interrupts A–D. These signals are interrupt
Pullup
inputs to the bridge on the secondary PCI bus.
resistor per
PCI spec
IRDY
J01
H03
I/O
PCI Bus
PCIR
Pullup
PCI initiator ready
resistor per
PCI spec
LOCK
M08
N08
I/O
PCI Bus
PCIR
SIGNAL
EXTERNAL
PARTS
DESCRIPTION
Pullup
PCI frame
resistor per
PCI spec
–
PCI grant outputs. These signals are used for
arbitration when the PCI bus is the secondary
bus and an external arbiter is not used. GNT0
is used as the REQ for the bridge when an
external arbiter is used.
This terminal functions as PCI LOCK when bit
12 (LOCK_EN) is set in the general control
register (see Section 4.65).
Pullup
resistor per
PCI spec Note: In lock mode, an external pullup resistor
is required to prevent the LOCK signal from
floating.
M66EN
L06
M06
I
PCI Bus
PCIR
66-MHz mode enable
0 = Secondary PCI bus and clock outputs
Pullup
operate at 33 MHz. If PCLK66_SEL is low then
resistor per the frequency will be 25 MHz.
PCI spec
1 = Secondary PCI bus and clock outputs
operate at 66 MHz. If PCLK66_SEL is low then
the frequency will be 50 MHz.
PAR
F01
G01
I/O
PCI Bus
PCIR
PERR
G02
G03
I/O
PCI Bus
PCIR
PME
L12
M12
I
LV
CMOS
VDD_33_
PCI Bus
PCIR
COMBIO
–
PCI bus parity
Pullup
PCI parity error
resistor per
PCI spec
Pullup resistor per PCI spec PCI power
management event. This terminal may be used
Pullup
resistor per to detect PME events from a PCI device on the
PCI spec secondary bus.
Note: The PME input buffer has hysteresis.
REQ5
REQ4
REQ3
REQ2
REQ1
REQ0
A12
C09
C08
A08
A06
A04
C09
A09
C08
C07
C06
A04
I
PRST
N07
L07
O
PCI Bus
PCIR
SERR
G03
G02
I/O
PCI Bus
PCIR
Pullup
PCI system error
resistor per
PCI spec
STOP
G01
H01
I/O
PCI Bus
PCIR
Pullup
PCI stop
resistor per
PCI spec
TRDY
H01
J02
I/O
PCI Bus
PCIR
Pullup
PCI target ready
resistor per
PCI spec
24
Overview
If unused, a
weak pullup
resistor per
PCI spec
–
PCI request inputs. These signals are used for
arbitration on the secondary PCI bus when an
external arbiter is not used. REQ0 is used as
the GNT for the bridge when an external
arbiter is used.
PCI reset. This terminal is an output to the
secondary PCI bus.
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SCPS212B – MAY 2009 – REVISED JULY 2009
Table 2-9. JTAG Terminals
SIGNAL
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
JTAG_TCK
M12
N12
I
LV
CMOS
VDD_33
EXTERNAL
PARTS
DESCRIPTION
JTAG test clock input. This signal provides the
clock for the internal TAP controller.
Optional
pullup
resistor
Note: This terminal has an internal active
pullup resistor. The pullup is active at all
times.
Note: This terminal should be tied to ground
or pulled low if JTAG is not required.
JTAG_TDI
N12
L10
I
LV
CMOS
VDD_33
JTAG test data input. Serial test instructions
and data are received on this terminal.
Optional
pullup
resistor
Note: This terminal has an internal active
pullup resistor. The pullup is active at all
times.
Note: This terminal can be left unconnected if
JTAG is not required.
JTAG_TDO
M11
N11
O
LV
CMOS
VDD_33
JTAG test data output. This terminal the serial
output for test instructions and data.
–
Note: This terminal can be left unconnected if
JTAG is not required.
JTAG_TMS
L10
L11
I
LV
CMOS
VDD_33
JTAG test mode select. The signal received at
JTAG_TMS is decoded by the internal TAP
controller to control test operations.
Optional
pullup
resistor
Note: This terminal has an internal active
pullup resistor. The pullup is active at all
times.
Note: This terminal can be left unconnected if
JTAG is not required.
JTAG_TRS
T
L09
L09
I
LV
CMOS
VDD_33
JTAG test reset. This terminal provides
Optional for asynchronous initialization of the
TAP controller.
Optional
pullup
resistor
Note: This terminal has an internal active
pullup resistor. The pullup is active at all
times.
Note: This terminal should be tied to ground
or pulled low if JTAG is not required.
Table 2-10. Miscellaneous Terminals
SIGNAL
CLKRUN_E
N
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
A13
C11
I
LV
CMOS
VDD_33
EXTERNAL
PARTS
Clock run enable
0 = Clock run support disabled
Optional
pullup
resistor
EXT_ARB_
EN
C10
A12
I
LV
CMOS
DESCRIPTION
VDD_33
1 = Clock run support enabled
Note: The CLKRUN_EN input buffer has an
internal active pulldown. This pulldown is
active at all times.
External arbiter enable
Optional
pullup
resistor
0 = Internal arbiter enabled
1 = External arbiter enabled
Note: The EXT_ARB_EN input buffer has an
internal active pulldown. This pulldown is
active at all times.
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Overview
25
XIO2001 PCI Express™ to PCI Bus Translation Bridge
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Table 2-10. Miscellaneous Terminals (continued)
SIGNAL
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
N09
N09
I/O
LV
CMOS
VDD_33
GPIO0 //
CLKRUN
EXTERNAL
PARTS
Optional
pullup
resistor
DESCRIPTION
General-purpose I/O 0/clock run. This terminal
functions as a GPIO controlled by bit 0
(GPIO0_DIR) in the GPIO control register (see
Section 4.59) or the clock run terminal. This
terminal is used as clock run input when the
bridge is placed in clock run mode.
Note: In clock run mode, an external pullup
resistor is required to prevent the CLKRUN
signal from floating.
Note: This terminal has an internal active
pullup resistor. The pullup is only active when
reset is asserted or when the GPIO is
configured as an input.
GPIO1 //
PWR_OVR
D
M09
M09
I/O
LV
CMOS
VDD_33
–
General-purpose I/O 1/power override. This
terminal functions as a GPIO controlled by bit 1
(GPIO1_DIR) in the GPIO control register (see
Section 4.59) or the power override output
terminal. GPIO1 becomes PWR_OVRD when
bits 22:20 (POWER_OVRD) in the general
control register are set to 001b or 011b (see
Section 4.65).
Note: This terminal has an internal active
pullup resistor. The pullup is only active when
reset is asserted or when the GPIO is
configured as an input.
GPIO2
N10
N10
I/O
LV
CMOS
VDD_33
General-purpose I/O 2. This terminal functions
as a GPIO controlled by bit 2 (GPIO2_DIR) in
the GPIO control register (see Section 4.59).
–
GPIO3 //
SDA
N11
L08
I/O
LV
CMOS
VDD_33
Optional
pullup
resistor
Note: This terminal has an internal active
pullup resistor. The pullup is only active when
reset is asserted or when the GPIO is
configured as an input.
GPIO3 or serial-bus data. This terminal
functions as serial-bus data if a pullup resistor
is detected on SCL or when the SBDETECT bit
is set in the Serial Bus Control and Status
Register (see Section 4.58). If no pullup is
detected then this terminal functions as
GPIO3.
Note: In serial-bus mode, an external pullup
resistor is required to prevent the SDA signal
from floating.
GPIO4 //
SCL
M10
M10
I/O
LV
CMOS
VDD_33
Optional
pullup
resistor
GPIO4 or serial-bus clock. This terminal
functions as serial-bus clock if a pullup resistor
is detected on SCL or when the SBDETECT bit
is set in the Serial Bus Control and Status
Register (see Section 4.58). If no pullup is
detected then this terminal functions as
GPIO4.
Note: In serial-bus mode, an external pullup
resistor is required to prevent the SCL signal
from floating.
Note: This terminal has an internal active
pullup resistor. The pullup is only active when
reset is asserted or when the GPIO is
configured as an input.
26
Overview
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Table 2-10. Miscellaneous Terminals (continued)
SIGNAL
GRST
ZGU
BALL #
ZAJ
BALL #
I/O
TYPE
CELL
TYPE
CLAMP
RAIL
N13
M11
I
LV
CMOS
_COMBIO
EXTERNAL
PARTS
VDD_33
–
DESCRIPTION
Global reset input. Asynchronously resets all
logic in device, including sticky bits and power
management state machines.
Note: The GRST input buffer has both
hysteresis and an internal active pullup. The
pullup is active at all times.
PCLK66_S
EL
B12
A11
I
LV
CMOS
VDD_33
PCI clock select. This terminal determines the
default PCI clock frequency driven out the
CLKOUTx terminals.
Optional
pulldown
resistor
0 = 50 MHz PCI Clock
1 = 66 MHz PCI Clock
Note: This terminal has an internal active
pullup resistor. This pullup is active at all times.
Note: M66EN terminal also has an affect of
PCI clock frequency.
SERIRQ
VREG_PD3
3
N08
D12
M08
E11
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I/O
I
PCI Bus
LV
CMOS
PCIR
VDD_33
_COMBIO
Pullup or
pulldown
resistor
Serial IRQ interface. This terminal functions as
a serial IRQ interface if a pullup is detected
when PERST is deasserted. If a pulldown is
detected, then the serial IRQ interface is
disabled.
Pulldown
resistor
3.3-V voltage regulator powerdown. This
terminal should always be tied directly to
ground or an optional pulldown resistor can be
used.
Overview
27
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
3
www.ti.com
Feature/Protocol Descriptions
This chapter provides a high-level overview of all significant device features. Figure 3-1 shows a simplified
block diagram of the basic architecture of the PCI-Express to PCI Bridge. The top of the diagram is the
PCI Express interface and the PCI bus interface is located at the bottom of the diagram.
PCI Express
Transmitter
PCI Express
Receiver
Power
Mgmt
GPIO
Configuration and
Memory Register
Clock
Generator
Serial
EEPROM
Serial
IRQ
Reset
Controller
PCI Bus Interface
Figure 3-1. XIO2001 Block Diagram
3.1
Power-Up/-Down Sequencing
The bridge contains both 1.5-V and 3.3-V power terminals. The following power-up and power-down
sequences describe how power is applied to these terminals.
In addition, the bridge has three resets: PERST, GRST and an internal power-on reset. These resets are
fully described in Section 3.2. The following power-up and power-down sequences describe how PERST
is applied to the bridge.
The application of the PCI Express reference clock (REFCLK) is important to the power-up/-down
sequence and is included in the following power-up and power-down descriptions.
28
Feature/Protocol Descriptions
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3.1.1
SCPS212B – MAY 2009 – REVISED JULY 2009
Power-Up Sequence
1.
2.
3.
4.
5.
Assert PERST to the device.
Apply 1.5-V and 3.3-V voltages.
Apply PCIR clamp voltage.
Apply a stable PCI Express reference clock.
To meet PCI Express specification requirements, PERST cannot be deasserted until the following two
delay requirements are satisfied:
– Wait a minimum of 100 µs after applying a stable PCI Express reference clock. The 100-µs limit
satisfies the requirement for stable device clocks by the deassertion of PERST.
– Wait a minimum of 100 ms after applying power. The 100-ms limit satisfies the requirement for
stable power by the deassertion of PERST.
See the power-up sequencing diagram in Figure 3-2.
VDD_15 and
VDDA_15
VDD_33 and
VDDA_33
PCIR
REFCLK
PERST
100 ms
100 ms
Figure 3-2. Power-Up Sequence
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Feature/Protocol Descriptions
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XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
3.1.2
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Power-Down Sequence
1.
2.
3.
4.
Assert PERST to the device.
Remove the reference clock.
Remove PCIR clamp voltage.
Remove 3.3-V and 1.5-V voltages.
See the power-down sequencing diagram in Figure 3-3. If the VDD_33_AUX terminal is to remain powered
after a system shutdown, then the bridge power-down sequence is exactly the same as shown in
Figure 3-3.
VDD_15 and
VDDA_15
VDD_33 and
VDDA_33
PCIR
REFCLK
PERST
Figure 3-3. Power-Down Sequence
3.2
Bridge Reset Features
There are five bridge reset options that include internally-generated power-on reset, resets generated by
asserting input terminals, and software-initiated resets that are controlled by sending a PCI Express hot
reset or setting a configuration register bit. Table 3-1 identifies these reset sources and describes how the
bridge responds to each reset.
Table 3-1. XIO2001 Reset Options
RESET
OPTION
XIO2001 FEATURE
RESET RESPONSE
Bridge
internallygenerated
power-on reset
During a power-on cycle, the bridge asserts an internal reset
and monitors the VDD_15_COMB terminal. When this terminal
reaches 90% of the nominal input voltage specification,
power is considered stable. After stable power, the bridge
monitors the PCI Express reference clock (REFCLK) and
waits 10 µs after active clocks are detected. Then, internal
power-on reset is deasserted.
When the internal power-on reset is asserted, all control
registers, state machines, sticky register bits, and power
management state machines are initialized to their default
state.
In addition, the XIO2001 asserts the internal PCI bus reset.
When GRST is asserted low, an internal power-on reset
occurs. This reset is asynchronous and functions during
both normal power states and VAUX power states.
When GRST is asserted low, all control registers, state
machines, sticky register bits, and power management
state machines are initialized to their default state. In
addition, the bridge asserts PCI bus reset (PRST). When
the rising edge of GRST occurs, the bridge samples the
state of all static control inputs and latches the information
internally. If an external serial EEPROM is detected, then a
download cycle is initiated. Also, the process to configure
and initialize the PCI Express link is started. The bridge
starts link training within 80 ms after GRST is deasserted.
Global reset
input
GRST
30
Feature/Protocol Descriptions
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Table 3-1. XIO2001 Reset Options (continued)
RESET
OPTION
PCI Express
reset input
PERST
XIO2001 FEATURE
This XIO2001 input terminal is used by an upstream PCI
Express device to generate a PCI Express reset and to
signal a system power good condition.
When PERST is asserted low, the XIO2001 generates an
internal PCI Express reset as defined in the PCI Express
specification.
PCI Express
training control
hot reset
RESET RESPONSE
When PERST is asserted low, all control register bits that
are not sticky are reset. Within the configuration register
maps, the sticky bits are indicated by the I symbol. Also, all
state machines that are not associated with sticky
functionality are reset.
When PERST transitions from low to high, a system power
good condition is assumed by the XIO2001.
In addition, the XIO2001 asserts the internal PCI bus reset.
Note: The system must assert PERST before power is
removed, before REFCLK is removed or before REFCLK
becomes unstable.
When the rising edge of PERST occurs, the XIO2001
samples the state of all static control inputs and latches
the information internally. If an external serial EEPROM is
detected, then a download cycle is initiated. Also, the
process to configure and initialize the PCI Express link is
started. The XIO2001 starts link training within 80 ms after
PERST is deasserted.
The XIO2001 responds to a training control hot reset
received on the PCI Express interface. After a training
control hot reset, the PCI Express interface enters the
DL_DOWN state.
In the DL_DOWN state, all remaining configuration register
bits and state machines are reset. All remaining bits
exclude sticky bits and EEPROM loadable bits. All
remaining state machines exclude sticky functionality and
EEPROM functionality.
Within the configuration register maps, the sticky bits are
indicated by the I symbol and the EEPROM loadable bits
are indicated by the † symbol.
In addition, the XIO2001 asserts the internal PCI bus reset.
PCI bus reset
PRST
3.3
3.3.1
System software has the ability to assert and deassert the
PRST terminal on the secondary PCI bus interface. This
terminal is the PCI bus reset.
When bit 6 (SRST) in the bridge control register at offset
3Eh (see Section 4.29) is asserted, the bridge asserts the
PRST terminal. A 0 in the SRST bit deasserts the PRST
terminal.
PCI Express Interface
External Reference Clock
The bridge requires either a differential, 100-MHz common clock reference or a single-ended, 125-MHz
clock reference. The selected clock reference must meet all PCI Express Electrical Specification
requirements for frequency tolerance, spread spectrum clocking, and signal electrical characteristics.
Spread Spectrum is an optional feature of the PCI Express Electrical Specification that is supported by
this bridge.
If the REFCLK125_SEL input is connected to VSS, then a differential, 100-MHz common clock reference is
expected by the XIO2001. If the REFCLK125_SEL terminal is connected to VDD_33, then a single-ended,
125-MHz clock reference is expected by the bridge
When the single-ended, 125-MHz clock reference option is enabled, the single-ended clock signal is
connected to the REFCLK+ terminal. The REFCLK– terminal is connected to one side of an external
capacitor with the other side of the capacitor connected to VSS.
When using a single-ended reference clock, care must be taken to ensure interoperability from a system
jitter standpoint. The PCI Express Base Specification does not ensure interoperability when using a
differential reference clock commonly used in PC applications along with a single-ended clock in a
non-common clock architecture. System jitter budgets will have to be verified to ensure interoperability.
See the PCI Express Jitter and BER White Paper from the PCI-SIG.
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Beacon
The bridge supports the PCI Express in-band beacon feature. Beacon is driven on the upstream PCI
Express link by the bridge to request the reapplication of main power when in the L2 link state. To enable
the beacon feature, bit 10 (BEACON_ENABLE) in the general control register at offset D4h is asserted.
See Section 4.65, General Control Register, for details.
If the bridge is in the L2 link state and beacon is enabled, when a secondary PCI bus device asserts PME,
then the bridge outputs the beacon signal on the upstream PCI Express link. The beacon signal frequency
is approximately 500 kHz ± 50% with a differential peak-to-peak amplitude of 500 mV and no
de-emphasis. Once the beacon is activated, the bridge continues to send the beacon signal until main
power is restored as indicated by PERST going inactive. At this time, the beacon signal is deactivated.
3.3.3
Wake
The bridge supports the PCI Express sideband WAKE feature. WAKE is an active low signal driven by the
bridge to request the reapplication of main power when in the L2 link state. Since WAKE is an
open-collector output, a system-side pullup resistor is required to prevent the signal from floating.
When the bridge is in the L2 link state and PME is received from a device on the secondary PCI bus, the
WAKE signal is asserted low as a wakeup mechanism. Once WAKE is asserted, the bridge drives the
signal low until main power is restored as indicated by PERST going inactive. At this time, WAKE is
deasserted.
3.3.4
Initial Flow Control Credits
The bridge flow control credits are initialized using the rules defined in the PCI Express Base
Specification. Table 3-2 identifies the initial flow control credit advertisement for the bridge.
Table 3-2. Initial Flow Control Credit Advertisements
CREDIT TYPE
3.3.5
INITIAL ADVERTISEMENT
Posted request headers (PH)
8
Posted request data (PD)
128
Non-posted header (NPH)
4
Non-posted data (NPD)
4
Completion header (CPLH)
0 (infinite)
Completion data (CPLD)
0 (infinite)
PCI Express Message Transactions
PCI Express messages are both initiated and received by the bridge. Table 3-3 outlines message support
within the bridge.
Table 3-3. Messages Supported by the Bridge
MESSAGE
SUPPORTED
BRIDGE ACTION
Assert_INTx
Yes
Transmitted upstream
Deassert_INTx
Yes
Transmitted upstream
PM_Active_State_Nak
Yes
Received and processed
PM_PME
Yes
Transmitted upstream
PME_Turn_Off
Yes
Received and processed
PME_TO_Ack
Yes
Transmitted upstream
ERR_COR
Yes
Transmitted upstream
ERR_NONFATAL
Yes
Transmitted upstream
ERR_FATAL
Yes
Transmitted upstream
Set_Slot_Power_Limit
Yes
Received and processed
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Table 3-3. Messages Supported by the Bridge (continued)
SUPPORTED
BRIDGE ACTION
Unlock
MESSAGE
No
Discarded
Hot plug messages
No
Discarded
Advanced switching messages
No
Discarded
Vendor defined type 0
No
Unsupported request
Vendor defined type 1
No
Discarded
All supported message transactions are processed per the PCI Express Base Specification.
3.4
3.4.1
PCI Bus Interface
I/O Characteristics
Figure 3-4 shows a 3-state bi-directional buffer that represents the I/O cell design for the PCI bus.
Section 7.7, Electrical Characteristics over Recommended Operating Conditions, provides the electrical
characteristics of the PCI bus I/O cell.
NOTE
The PCI bus interface on the bridge meets the ac specifications of the PCI Local Bus
Specification. Additionally, PCI bus terminals (input or I/O) must be held high or low to
prevent them from floating.
PCIR
Figure 3-4. 3-State Bidirectional Buffer
3.4.2
Clamping Voltage
In the bridge, the PCI bus I/O drivers are powered from the VDD_33 power rail. Plus, the I/O driver cell is
tolerant to input signals with 5-V peak-to-peak amplitudes.
For PCI bus interfaces operating at 50MHz or 66 MHz, all devices are required to output only 3.3-V
peak-to-peak signal amplitudes. For PCI bus interfaces operating at 25-MHz or 33-MHz, devices may
output either 3.3-V or 5-V peak-to-peak signal amplitudes. The bridge accommodates both signal
amplitudes.
Each PCI bus I/O driver cell has a clamping diode connected to the internal VCCP voltage rail that protects
the cell from excessive input voltage. The internal VCCP rail is connected to two PCIR terminals. If the PCI
signaling is 3.3-V, then PCIR terminals are connected to a 3.3-V power supply via a 1kΩ resistor. If the
PCI signaling is 5-V, then the PCIR terminals are connected to a 5-V power supply via a 1kΩ resistor.
The PCI bus signals attached to the VCCP clamping voltage are identified as follows
• Table 2-8, PCI System Terminals, all terminal names except for PME
• Table 2-10, Miscellaneous Terminals, the terminal name SERIRQ.
3.4.3
PCI Bus Clock Run
The bridge supports the clock run protocol as specified in the PCI Mobile Design Guide. When the clock
run protocol is enabled, the bridge assumes the role of the central resource master.
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To enable the clock run function, terminal CLKRUN_EN is asserted high. Then, terminal GPIO0 is enabled
as the CLKRUN signal. An external pullup resistor must be provided to prevent the CLKRUN signal from
floating To verify the operational status of the PCI bus clocks, bit 0 (SEC_CLK_STATUS) in the clock run
status register at offset DAh (see Section 4.68) is read.
Since the bridge has several unique features associated with the PCI bus interface, the system designer
must consider the following interdependencies between these features and the CLKRUN feature:
1. If the system designer chooses to generate the PCI bus clock externally, then the CLKRUN mode of
the bridge must be disabled. The central resource function within the bridge only operates as a
CLKRUN master and does not support the CLKRUN slave mode.
2. If the central resource function has stopped the PCI bus clocks, then the bridge still detects INTx state
changes and will generate and send PCI Express messages upstream.
3. If the serial IRQ interface is enabled and the central resource function has stopped the PCI bus clocks,
then any PCI bus device that needs to report an IRQ interrupt asserts CLKRUN to start the bus clocks.
4. When a PCI bus device asserts CLKRUN, the central resource function turns on PCI bus clocks for a
minimum of 512 cycles.
5. If the serial IRQ function detects an IRQ interrupt, then the central resource function keeps the PCI bus
clocks running until the IRQ interrupt is cleared by software.
6. If the central resource function has stopped the PCI bus clocks and the bridge receives a downstream
transaction that is forwarded to the PCI bus interface, then the bridge asserts CLKRUN to start the bus
clocks.
7. The central resource function is reset by PCI bus reset (PRST) assuring that clocks are present during
PCI bus resets.
3.4.4
PCI Bus External Arbiter
The bridge supports an external arbiter for the PCI bus. Terminal (EXT_ARB_EN), when asserted high,
enables the use of an external arbiter.
When an external arbiter is enabled, GNT0 is connected to the external arbiter as the REQ for the bridge.
Likewise, REQ0 is connected to the external arbiter as the GNT for the bridge.
3.4.5
MSI Messages Generated from the Serial IRQ Interface
When properly configured, the bridge converts PCI bus serial IRQ interrupts into PCI Express message
signaled interrupts (MSI). classic PCI configuration register space is provided to enable this feature. The
following list identifies the involved configuration registers:
1. Command register at offset 04h, bit 2 (MASTER_ENB) is asserted (see Table 4-2).
2. MSI message control register at offset 52h, bits 0 (MSI_EN) and 6:4 (MM_EN) enable single and
multiple MSI messages, respectively (see Section 4.42).
3. MSI message address register at offsets 54h and 58h specifies the message memory address. A
nonzero address value in offset 58h initiates 64-bit addressing (see Section 4.37 and Section 4.44).
4. MSI message data register at offset 5Ch specifies the system interrupt message (see Section 4.45).
5. Serial IRQ mode control register at offset E0h specifies the serial IRQ bus format (see Section 4.72).
6. Serial IRQ edge control register at offset E2h selects either level or edge mode interrupts (see
Section 4.73).
7. Serial IRQ status register at offset E4h reports level mode interrupt status (see Section 4.74).
A PCI Express MSI is generated based on the settings in the serial IRQ edge control register. If the
system is configured for edge mode, then an MSI message is sent when the corresponding serial IRQ
interface sample phase transitions from low to high. If the system is configured for level mode, then an
MSI message is sent when the corresponding IRQ status bit in the serial IRQ status register changes from
low to high.
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The bridge has a dedicated SERIRQ terminal for all PCI bus devices that support serialized interrupts.
This SERIRQ interface is synchronous to the PCI bus clock input (CLK) frequency. The bridge always
generates a 17-phase serial IRQ stream. Internally, the bridge detects only 16 IRQ interrupts, IRQ0 frame
through IRQ15 frame. The IOCHCK frame is not monitored by the serial IRQ state machine and never
generates an IRQ interrupt or MSI message.
The multiple message enable (MM_EN) field determines the number of unique MSI messages that are
sent upstream on the PCI Express link. From 1 message to 16 messages, in powers of 2, are selectable.
If fewer than 16 messages are selected, then the mapping from IRQ interrupts to MSI messages is
aliased. Table 3-4 illustrates the IRQ interrupt to MSI message mapping based on the number of enabling
messages.
Table 3-4. IRQ Interrupt to MSI Message Mapping
IRQ
INTERRUPT
1 MESSAGE
ENABLED
2 MESSAGES
ENABLED
4 MESSAGES
ENABLED
8 MESSAGES ENABLED
16 MESSAGES
ENABLED
IRQ0
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #0
IRQ1
MSI MSG #0
MSI MSG #1
MSI MSG #1
MSI MSG #1
MSI MSG #1
IRQ2
MSI MSG #0
MSI MSG #0
MSI MSG #2
MSI MSG #2
MSI MSG #2
IRQ3
MSI MSG #0
MSI MSG #1
MSI MSG #3
MSI MSG #3
MSI MSG #3
IRQ4
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #4
MSI MSG #4
IRQ5
MSI MSG #0
MSI MSG #1
MSI MSG #1
MSI MSG #5
MSI MSG #5
IRQ6
MSI MSG #0
MSI MSG #0
MSI MSG #2
MSI MSG #6
MSI MSG #6
IRQ7
MSI MSG #0
MSI MSG #1
MSI MSG #3
MSI MSG #7
MSI MSG #7
IRQ8
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #8
IRQ9
MSI MSG #0
MSI MSG #1
MSI MSG #1
MSI MSG #1
MSI MSG #9
IRQ10
MSI MSG #0
MSI MSG #0
MSI MSG #2
MSI MSG #2
MSI MSG #10
IRQ11
MSI MSG #0
MSI MSG #1
MSI MSG #3
MSI MSG #3
MSI MSG #11
IRQ12
MSI MSG #0
MSI MSG #0
MSI MSG #0
MSI MSG #4
MSI MSG #12
IRQ13
MSI MSG #0
MSI MSG #1
MSI MSG #1
MSI MSG #5
MSI MSG #13
IRQ14
MSI MSG #0
MSI MSG #0
MSI MSG #2
MSI MSG #6
MSI MSG #14
IRQ15
MSI MSG #0
MSI MSG #1
MSI MSG #3
MSI MSG #7
MSI MSG #15
The MSI message format is compatible with the PCI Express request header format for 32-bit and 64-bit
memory write transactions. The system message and message number fields are included in bytes 0 and
1 of the data payload.
3.4.6
PCI Bus Clocks
The bridge has seven PCI bus clock outputs and one PCI bus clock input. Up to six PCI bus devices are
supported by the bridge.
Terminal PCLK66_SEL selects the default operating frequency. This signal works in conjunction with
terminal M66EN to determine the final output frequency. When PCLK66_SEL is asserted high then the
clock frequency will be either 66-MHz or 33-MHz depending on the state of M66EN. When M66EN is
asserted high then the clock frequency will be 66-MHz, when M66EN is de-asserted the clock frequency
will be 33-MHz. When PCLK66_SEL is de-asserted then the clock frequency will be either 50-MHz or
25-MHz. When M66EN is asserted high then the clock frequency will be 50-MHz, when M66EN is
de-asserted the clock frequency will be 25-MHz. The clock control register at offset D8h provides 7 control
bits to individually enable or disable each PCI bus clock output (see Section 4.66). The register default is
enabled for all 7 outputs.
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The PCI bus clock (CLK) input provides the clock to the internal PCI bus core and serial IRQ core. When
the internal PCI bus clock source is selected, PCI bus clock output 6 (CLKOUT6) is connected to the PCI
bus clock input (CLK). When an external PCI bus clock source is selected, the external clock source is
connected to the PCI bus clock input (CLK). For external clock mode, all seven CLKOUT6:0 terminals
must be disabled using the clock control register at offset D8h (see Section 4.66).
3.5
PCI Port Arbitration
The internal PCI port arbitration logic supports up to six external PCI bus devices plus the bridge. This
bridge supports a classic PCI arbiter.
3.5.1
Classic PCI Arbiter
The classic PCI arbiter is configured through the classic PCI configuration space at offset DCh. Table 3-5
identifies and describes the registers associated with classic PCI arbitration mode.
Table 3-5. Classic PCI Arbiter Registers
PCI OFFSET
REGISTER NAME
Classic PCI configuration
register DCh
Arbiter control
(see Section 4.69)
DESCRIPTION
Contains a two-tier priority scheme for the bridge and six PCI bus devices. The
bridge defaults to the high priority tier. The six PCI bus devices default to the low
priority tier. A bus parking control bit (bit 7, PARK) is provided.
Classic PCI configuration
register DDh
Arbiter request mask
(see Section 4.70)
Six mask bits provide individual control to block each PCI Bus REQ input. Bit 7
(ARB_TIMEOUT) in the arbiter request mask register enables generating timeout
status if a PCI device does not respond within 16 PCI bus clocks. Bit 6
(AUTO_MASK) in the arbiter request mask register automatically masks a PCI bus
REQ if the device does not respond after GNT is issued. The AUTO_MASK bit is
cleared to disable any automatically generated mask.
Classic PCI configuration
register DEh
Arbiter time-out status
(see Section 4.71)
When bit 7 (ARB_TIMEOUT) in the arbiter request mask register is asserted,
timeout status for each PCI bus device is reported in this register.
3.6
Configuration Register Translation
PCI Express configuration register transactions received by the bridge are decoded based on the
transaction’s destination ID. These configuration transactions can be broken into three subcategories: type
0 transactions, type 1 transactions that target the secondary bus, and type 1 transactions that target a
downstream bus other than the secondary bus.
PCI Express type 0 configuration register transactions always target the configuration space and are never
passed on to the secondary interface.
Type 1 configuration register transactions that target a device on the secondary bus are converted to type
0 configuration register transactions on the PCI bus. Figure 3-5 shows the address phase of a type 0
configuration transaction on the PCI bus as defined by the PCI specification.
Figure 3-5. Type 0 Configuration Transaction Address Phase Encoding
In addition, the bridge converts the destination ID device number to one of the AD[31:16] lines as the
IDSEL signal. The implemented IDSEL signal mapping is shown in Table 3-6.
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Table 3-6. Type 0 Configuration Transaction
IDSEL Mapping
DEVICE
NUMBER
AD[31:16]
00000
0000 0000 0000 0001
00001
0000 0000 0000 0010
00010
0000 0000 0000 0100
00011
0000 0000 0000 1000
00100
0000 0000 0001 0000
00101
0000 0000 0010 0000
00110
0000 0000 0100 0000
00111
0000 0000 1000 0000
01000
0000 0001 0000 0000
01001
0000 0010 0000 0000
01010
0000 0100 0000 0000
01011
0000 1000 0000 0000
01100
0001 0000 0000 0000
01101
0010 0000 0000 0000
01110
0100 0000 0000 0000
01111
1000 0000 0000 0000
1xxxx
0000 0000 0000 0000
Type 1 configuration registers transactions that target a downstream bus other then the secondary bus are
output on the PCI bus as type 1 PCI configuration transactions. Figure 3-6 shows the address phase of a
type 1 configuration transaction on the PCI bus as defined by the PCI specification.
Figure 3-6. Type 1 Configuration Transaction Address Phase Encoding
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PCI Interrupt Conversion to PCI Express Messages
The bridge converts interrupts from the PCI bus sideband interrupt signals to PCI Express interrupt
messages.
Table 3-7, Figure 3-7, and Figure 3-8 illustrate the format for both the assert and deassert INTx
messages.
Table 3-7. Interrupt
Mapping In The Code Field
INTERRUPT
CODE FIELD
INTA
00
INTB
01
INTC
10
INTD
11
Figure 3-7. PCI Express ASSERT_INTX Message
Figure 3-8. PCI Express DEASSERT_INTX Message
3.8
PME Conversion to PCI Express Messages
When the PCI bus PME input transitions low, the bridge generates and sends a PCI Express PME
message upstream. The requester ID portion of the PME message uses the stored value in the secondary
bus number register as the bus number, 0 as the device number, and 0 as the function number. The Tag
field for each PME message is 00h. A PME message is sent periodically until the PME signal transitions
high.
Figure 3-9 illustrates the format for a PCI Express PME message.
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Figure 3-9. PCI Express PME Message
3.9
PCI Express to PCI Bus Lock Conversion
The bus-locking protocol defined in the PCI Express Base Specification and PCI Local Bus Specification is
provided on the bridge as an additional compatibility feature. The PCI bus LOCK signal is a dedicated
output that is enabled by setting bit 12 in the general control register at offset D4h. See Section 4.65,
General Control Register, for details.
NOTE
The use of LOCK is only supported by PCI-Express to PCI Bridges in the downstream
direction (away from the root complex).
PCI Express locked-memory read request transactions are treated the same as PCI Express memory read
transactions except that the bridge returns a completion for a locked-memory read. Also, the bridge uses
the PCI LOCK protocol when initiating the memory read transaction on the PCI bus.
When a PCI Express locked-memory read request transaction is received and the bridge is not already
locked, the bridge arbitrates for use of the LOCK terminal by asserting REQ. If the bridge receives GNT
and the LOCK terminal is high, then the bridge drives the LOCK terminal low after the address phase of
the first locked-memory read transaction to take ownership of LOCK. The bridge continues to assert
LOCK except during the address phase of locked transactions. If the bridge receives GNT and the LOCK
terminal is low, then the bridge deasserts its REQ and waits until LOCK is high and the bus is idle before
re-arbitrating for the use of LOCK.
CLK
FRAME
LOCK
AD
Address
Data
IRDY
TRDY
DEVSEL
Figure 3-10. Starting a Locked Sequence
Once the bridge has ownership of LOCK, the bridge initiates the lock read as a memory read transaction
on the PCI bus. When the target of the locked-memory read returns data, the bridge is considered locked
and all transactions not associated with the locked sequence are blocked by the bridge.
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Figure 3-11. Continuing a Locked Sequence
Because PCI Express does not have a unique locked-memory write request packet, all PCI Express
memory write requests that are received while the bridge is locked are considered part of the locked
sequence and are transmitted to PCI as locked-memory write transactions.
The bridge terminates the locked sequence when an unlock message is received from PCI Express and
all previous locked transactions have been completed.
CLK
FRAME
LOCK
IRDY
Figure 3-12. Terminating a Locked Sequence
In the erroneous case that a normal downstream memory read request is received during a locked
sequence, the bridge responds with an unsupported request completion status. Note that this condition
must never occur, because the PCI Express Specification requires the root complex to block normal
memory read requests at the source. All locked sequences that end successfully or with an error condition
must be immediately followed by an unlock message. This unlock message is required to return the bridge
to a known unlocked state.
3.10 Two-Wire Serial-Bus Interface
The bridge provides a two-wire serial-bus interface to load subsystem identification information and
specific register defaults from an external EEPROM. The serial-bus interface signals (SDA and SCL) are
shared with two of the GPIO terminals (3 and 4). If the serial bus interface is enabled, then the GPIO3 and
GPIO4 terminals are disabled. If the serial bus interface is disabled, then the GPIO terminals operate as
described in Section 3.13.
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3.10.1 Serial-Bus Interface Implementation
To enable the serial-bus interface, a pullup resistor must be implemented on the SCL signal. At the rising
edge of PERST or GRST, whichever occurs later in time, the SCL terminal is checked for a pullup resistor.
If one is detected, then bit 3 (SBDETECT) in the serial-bus control and status register (see Section 4.58)
is set. Software may disable the serial-bus interface at any time by writing a 0b to the SBDETECT bit. If
no external EEPROM is required, then the serial-bus interface is permanently disabled by attaching a
pulldown resistor to the SCL signal.
The bridge implements a two-terminal serial interface with one clock signal (SCL) and one data signal
(SDA). The SCL signal is a unidirectional output from the bridge and the SDA signal is bidirectional. Both
are open-drain signals and require pullup resistors. The bridge is a bus master device and drives SCL at
approximately 60 kHz during data transfers and places SCL in a high-impedance state (0 frequency)
during bus idle states. The serial EEPROM is a bus slave device and must acknowledge a slave address
equal to A0h. Figure 3-13 illustrates an example application implementing the two-wire serial bus.
VDD_33
Serial
EEPROM
XIO2001
A0
A1
SCL
GPIO4 // SCL
A2
SDA
GPIO3 // SDA
Figure 3-13. Serial EEPROM Application
3.10.2 Serial-Bus Interface Protocol
All data transfers are initiated by the serial-bus master. The beginning of a data transfer is indicated by a
start condition, which is signaled when the SDA line transitions to the low state while SCL is in the high
state, as illustrated in Figure 3-14. The end of a requested data transfer is indicated by a stop condition,
which is signaled by a low-to-high transition of SDA while SCL is in the high state, as shown in
Figure 3-14. Data on SDA must remain stable during the high state of the SCL signal, as changes on the
SDA signal during the high state of SCL are interpreted as control signals, that is, a start or stop condition.
Figure 3-14. Serial-Bus Start/Stop Conditions and Bit Transfers
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Data is transferred serially in 8-bit bytes. During a data transfer operation, the exact number of bytes that
are transmitted is unlimited. However, each byte must be followed by an acknowledge bit to continue the
data transfer operation. An acknowledge (ACK) is indicated by the data byte receiver pulling the SDA
signal low, so that it remains low during the high state of the SCL signal. Figure 3-15 illustrates the
acknowledge protocol.
SCL From
Master
1
2
3
7
8
9
SDA Output
By Transmitter
SDA Output
By Receiver
Figure 3-15. Serial-Bus Protocol Acknowledge
The bridge performs three basic serial-bus operations: single byte reads, single byte writes, and multibyte
reads. The single byte operations occur under software control. The multibyte read operations are
performed by the serial EEPROM initialization circuitry immediately after a PCI Express reset. See
Section 3.10.3, Serial-Bus EEPROM Application, for details on how the bridge automatically loads the
subsystem identification and other register defaults from the serial-bus EEPROM.
Figure 3-16 illustrates a single byte write. The bridge issues a start condition and sends the 7-bit slave
device address and the R/W command bit is equal to 0b. A 0b in the R/W command bit indicates that the
data transfer is a write. The slave device acknowledges if it recognizes the slave address. If no
acknowledgment is received by the bridge, then bit 1 (SB_ERR) is set in the serial-bus control and status
register (PCI offset B3h, see Section 4.58). Next, the EEPROM word address is sent by the bridge, and
another slave acknowledgment is expected. Then the bridge delivers the data byte MSB first and expects
a final acknowledgment before issuing the stop condition.
Figure 3-16. Serial-Bus Protocol – Byte Write
Figure 3-17 illustrates a single byte read. The bridge issues a start condition and sends the 7-bit slave
device address and the R/W command bit is equal to 0b (write). The slave device acknowledges if it
recognizes the slave address. Next, the EEPROM word address is sent by the bridge, and another slave
acknowledgment is expected. Then, the bridge issues a restart condition followed by the 7-bit slave
address and the R/W command bit is equal to 1b (read). Once again, the slave device responds with an
acknowledge. Next, the slave device sends the 8-bit data byte, MSB first. Since this is a 1-byte read, the
bridge responds with no acknowledge (logic high) indicating the last data byte. Finally, the bridge issues a
stop condition.
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Figure 3-17. Serial-Bus Protocol – Byte Read
Figure 3-18 illustrates the serial interface protocol during a multi-byte serial EEPROM download. The
serial-bus protocol starts exactly the same as a 1-byte read. The only difference is that multiple data bytes
are transferred. The number of transferred data bytes is controlled by the bridge master. After each data
byte, the bridge master issues acknowledge (logic low) if more data bytes are requested. The transfer
ends after a bridge master no acknowledge (logic high) followed by a stop condition.
Figure 3-18. Serial-Bus Protocol – Multibyte Read
Bit 7 (PROT_SEL) in the serial-bus control and status register changes the serial-bus protocol. Each of
the three previous serial-bus protocol figures illustrates the PROT_SEL bit default (logic low). When this
control bit is asserted, the word address and corresponding acknowledge are removed from the serial-bus
protocol. This feature allows the system designer a second serial-bus protocol option when selecting
external EEPROM devices.
3.10.3 Serial-Bus EEPROM Application
The registers and corresponding bits that are loaded through the EEPROM are provided in Table 3-8.
Table 3-8. EEPROM Register Loading Map
SERIAL EEPROM WORD
ADDRESS
BYTE DESCRIPTION
00h
PCI-Express to PCI bridge function indicator (00h)
01h
Number of bytes to download (25h)
02h
PCI 44h, subsystem vendor ID, byte 0
03h
PCI 45h, subsystem vendor ID, byte 1
04h
PCI 46h, subsystem ID, byte 0s
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05h
PCI 47h, subsystem ID, byte 1s
06h
PCI D4h, general control, byte 0
07h
PCI D5h, general control, byte 1
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Table 3-8. EEPROM Register Loading Map (continued)
SERIAL EEPROM WORD
ADDRESS
BYTE DESCRIPTION
08h
PCI D6h, general control, byte 2
09h
PCI D7h, general control, byte 3
0Ah
PCI D8h, clock control
0Bh
PCI D9h, clock mask
0Ch
Reserved—no bits loaded
0Dh
PCI DCh, arbiter control
0Eh
PCI DDh, arbiter request mask
0Fh
PCI C0h, control and diagnostic register, byte 0
10h
PCI C1h, control and diagnostic register, byte 1
11h
PCI C2h, control and diagnostic register, byte 2
12h
PCI C3h, control and diagnostic register, byte 3
13h
PCI C4h, control and diagnostic register, byte 0
14h
PCI C5h, control and diagnostic register, byte 1
15h
PCI C6h, control and diagnostic register, byte 2
15h
PCI C6h, control and diagnostic register, byte 2
16h
PCI C7h, control and diagnostic register, byte 3
17h
PCI C8h, control and diagnostic register, byte 0
18h
PCI C9h, control and diagnostic register, byte 1
19h
PCI CAh, control and diagnostic register, byte 2
1Ah
PCI CBh, control and diagnostic register, byte 3
1Bh
Reserved—no bits loaded
1Ch
Reserved—no bits loaded
1Dh
PCI E0h, serial IRQ mode control
1Eh
PCI E2h, serial IRQ edge control, byte 0
1Fh
PCI E3h, serial IRQ edge control, byte 1
20h
PCI E8h, PFA_REQ_LENGTH_LIMIT
21h
PCI E9h, PFA_REQ_CNT_LIMIT
22h
PCI EAh, CACHE_TMR_XFR_LIMIT
23h
PCI ECh, CACHE_TIMER_LOWER_LIMIT, Byte 0
24h
PCI EDh, CACHE_TIMER_LOWER_LIMIT, Byte 1
25h
PCI EEh, CACHE_TIMER_UPPER_LIMIT, Byte 0
26h
PCI EFh, CACHE_TIMER_UPPER_LIMIT, Byte 1
27h
End-of-list indicator (80h)
This format must be explicitly followed for the bridge to correctly load initialization values from a serial
EEPROM. All byte locations must be considered when programming the EEPROM.
The serial EEPROM is addressed by the bridge at slave address 1010 000b. This slave address is
internally hardwired and cannot be changed by the system designer. Therefore, all three hardware
address bits for the EEPROM are tied to VSS to achieve this address. The serial EEPROM in the sample
application circuit (Figure 3-13) assumes the 1010b high-address nibble. The lower three address bits are
terminal inputs to the chip, and the sample application shows these terminal inputs tied to VSS.
During an EEPROM download operation, bit 4 (ROMBUSY) in the serial-bus control and status register is
asserted. After the download is finished, bit 0 (ROM_ERR) in the serial-bus control and status register
may be monitored to verify a successful download.
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3.10.4 Accessing Serial-Bus Devices Through Software
The bridge provides a programming mechanism to control serial-bus devices through system software.
The programming is accomplished through a doubleword of PCI configuration space at offset B0h.
Table 3-9 lists the registers that program a serial-bus device through software.
Table 3-9. Registers Used To Program Serial-Bus Devices
PCI OFFSET
REGISTER NAME
DESCRIPTION
B0h
Serial-bus data (see
Section 4.55)
Contains the data byte to send on write commands or the received data byte on read
commands.
B1h
Serial-bus word address
(see Section 4.56)
The content of this register is sent as the word address on byte writes or reads. This register is
not used in the quick command protocol. Bit 7 (PROT_SEL) in the serial-bus control and status
register (offset B3h, see Section 4.58) is set to 1b to enable the slave address to be sent.
B2h
Serial-bus slave address
(see Section 4.57)
Write transactions to this register initiate a serial-bus transaction. The slave device address and
the R/W command selector are programmed through this register.
B3h
Serial-bus control and
status (see Section 4.58)
Serial interface enable, busy, and error status are communicated through this register. In
addition, the protocol-select bit (PROT_SEL) and serial-bus test bit (SBTEST) are programmed
through this register.
To access the serial EEPROM through the software interface, the following steps are performed:
1. The control and status byte is read to verify the EEPROM interface is enabled (SBDETECT asserted)
and not busy (REQBUSY and ROMBUSY deasserted).
2. The serial-bus word address is loaded. If the access is a write, then the data byte is also loaded.
3. The serial-bus slave address and R/W command selector byte is written.
4. REQBUSY is monitored until this bit is deasserted.
5. SB_ERR is checked to verify that the serial-bus operation completed without error. If the operation is a
read, then the serial-bus data byte is now valid.
3.11 Advanced Error Reporting Registers
In the extended PCI Express configuration space, the bridge supports the advanced error reporting
capabilities structure. For the PCI Express interface, both correctable and uncorrectable error statuses are
provided. For the PCI bus interface, secondary uncorrectable error status is provided. All uncorrectable
status bits have corresponding mask and severity control bits. For correctable status bits, only mask bits
are provided.
Both the primary and secondary interfaces include first error pointer and header log registers. When the
first error is detected, the corresponding bit position within the uncorrectable status register is loaded into
the first error pointer register. Likewise, the header information associated with the first failing transaction
is loaded into the header log. To reset this first error control logic, the corresponding status bit in the
uncorrectable status register is cleared by a writeback of 1b.
For systems that require high data reliability, ECRC is fully supported on the PCI Express interface. The
primary side advanced error capabilities and control register has both ECRC generation and checking
enable control bits. When the checking bit is asserted, all received TLPs are checked for a valid ECRC
field. If the generation bit is asserted, then all transmitted TLPs contain a valid ECRC field.
3.12 Data Error Forwarding Capability
The bridge supports the transfer of data errors in both directions.
If a downstream PCI Express transaction with a data payload is received that targets the internal PCI bus
and the EP bit is set indicating poisoned data, then the bridge must ensure that this information is
transferred to the PCI bus. To do this, the bridge forces a parity error on each PCI bus data phase by
inverting the parity bit calculated for each double-word of data.
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If the bridge is the target of a PCI transaction that is forwarded to the PCI Express interface and a data
parity error is detected, then this information is passed to the PCI Express interface. To do this, the bridge
sets the EP bit in the upstream PCI Express header.
3.13 General-Purpose I/O Interface
Up to five general-purpose input/output (GPIO) terminals are provided for system customization. These
GPIO terminals are 3.3-V tolerant.
The exact number of GPIO terminals varies based on implementing the clock run, power override, and
serial EEPROM interface features. These features share four of the five GPIO terminals. When any of the
three shared functions are enabled, the associated GPIO terminal is disabled.
All five GPIO terminals are individually configurable as either inputs or outputs by writing the
corresponding bit in the GPIO control register at offset B4h (See Section 4.59). A GPIO data register at
offset B6h exists to either read the logic state of each GPIO input or to set the logic state of each GPIO
output. The power-up default state for the GPIO control register is input mode.
3.14 Set Slot Power Limit Functionality
The PCI Express Specification provides a method for devices to limit internal functionality and save power
based on the value programmed into the captured slot power limit scale (CSPLS) and capture slot power
limit value (CSPLV) fields of the PCI Express device capabilities register at offset 74h. See Section 4.49,
Device Capabilities Register, for details. The bridge writes these fields when a set slot power limit
message is received on the PCI Express interface.
After the deassertion of PERST, the XIO2001 compares the information within the CSPLS and CSPLV
fields of the device capabilities register to the minimum power scale (MIN_POWER_SCALE) and minimum
power value (MIN_POWER_VALUE) fields in the general control register at offset D4h. See Section 4.65,
General Control Register, for details. If the CSPLS and CSPLV fields are less than the
MIN_POWER_SCALE and MIN_POWER_VALUE fields, respectively, then the bridge takes the
appropriate action that is defined below.
The power usage action is programmable within the bridge. The general control register includes a 3-bit
POWER_OVRD field. This field is programmable to the following options:
1. Ignore slot power limit fields.
2. Assert the PWR_OVRD terminal.
3. Disable secondary clocks as specified by the clock mask register at offset D9h (see Section 4.67).
4. Disable secondary clocks as specified by the clock mask register and assert the PWR_OVRD terminal.
5. Respond with unsupported request to all transactions except type 0/1 configuration transactions and
set slot power limit messages
3.15 PCI Express and PCI Bus Power Management
The bridge supports both software-directed power management and active state power management
through standard PCI configuration space. Software-directed registers are located in the power
management capabilities structure located at offset 48h (see Section 4.31). Active state power
management control registers are located in the PCI Express capabilities structure located at offset 70h
(see Section 4.41).
During software-directed power management state changes, the bridge initiates link state transitions to L1
or L2/L3 after a configuration write transaction places the device in a low power state. The power
management state machine is also responsible for gating internal clocks based on the power state.
Table 3-10 identifies the relationship between the D-states and bridge clock operation.
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Table 3-10. Clocking In Low Power States
D0/L0
D1/L1
D2/L1
D3/L2/L3
PCI express reference clock input (REFCLK)
CLOCK SOURCE
On
On
On
On/Off
Internal PCI bus clock to bridge function
On
Off
Off
Off
The link power management (LPM) state machine manages active state power by monitoring the PCI
Express transaction activity. If no transactions are pending and the transmitter has been idle for at least
the minimum time required by the PCI Express Specification, then the LPM state machine transitions the
link to either the L0s or L1 state. By reading the bridge’s L0s and L1 exit latency in the link capabilities
register, the system software may make an informed decision relating to system performance versus
power savings. The ASLPMC field in the link control register provides an L0s only option, L1 only option,
or both L0s and L1 option.
3.16 Auto Pre-Fetch Agent
The auto pre-fetch agent is an internal logic module that will generate speculative read requests on behalf
of a PCI master to improve upstream memory read performance.
The auto pre-fetch agent will generate a read thread on the PCI-express bus when it receives an
upstream prefetchable memory read request on the PCI bus. A read thread is a sequence of one or more
read requests with contiguous read addresses. The first read of thread will be started by a master on the
PCI bus requesting a read that is forwarded to the root complex by the bridge. Each subsequent read in
the thread will be initiated by the auto pre-fetch agent. Each subsequent read will use the address that
immediately follows the last address of data in the previous read of the thread. Each read request in the
thread will be assigned to an upstream request processor. The pre-fetch agent can issue reads for two
threads at one time, alternating between the threads.
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Classic PCI Configuration Space
The programming model of the XIO2001 PCI-Express to PCI bridge is compliant to the classic PCI-to-PCI
bridge programming model. The PCI configuration map uses the type 1 PCI bridge header.
All bits marked with a are sticky bits and are reset by a global reset (GRST) or the internally-generated
power-on reset. All bits marked with a I are reset by a PCI Express reset (PERST), a GRST, or the
internally-generated power-on reset. The remaining register bits are reset by a PCI Express hot reset,
PERST, GRST, or the internally-generated power-on reset.
Table 4-1. Classic PCI Configuration Register Map
REGISTER NAME
OFFSET
Device ID
Vendor ID
000h
Status
Command
004h
Class code
BIST
Header type
Latency timer
Revision ID
008h
Cache line size
00Ch
Device control base address
010h
Reserved
Secondary latency timer
Subordinate bus number
014h
Secondary bus number
Primary bus number
018h
I/O limit
I/O base
01Ch
Secondary status
Memory limit
Prefetchable memory limit
Memory base
020h
Prefetchable memory base
024h
Prefetchable base upper 32 bits
028h
Prefetchable limit upper 32 bits
02Ch
I/O limit upper 16 bits
I/O base upper 16 bits
Reserved
030h
Capabilities pointer
Expansion ROM base address
038h
Bridge control
Interrupt pin
Interrupt line
03Ch
Reserved
Next item pointer
SSID/SSVID CAP ID
040h
Subsystem ID (1)
Subsystem vendor ID (1)
Power management capabilities
PM Data
Next item pointer
PMCSR_BSE
044h
PM CAP ID
Power management CSR
MSI message control
Next item pointer
MSI CAP ID
MSI message address
04Ch
050h
058h
MSI message data
05Ch
MSI Mask Bits Register
060h
MSI Pending Bits Register
064h
Reserved
068h–06Ch
PCI Express capabilities register
Next item pointer
PCI Express capability ID
Device Capabilities
Device status
Device control
Link status
070h
074h
Link Capabilities
078h
07Ch
Link control
Slot Capabilities
48
048h
054h
MSI upper message address
Reserved
(1)
034h
080h
084h
Slot Status
Slot Control
088h
Root Capabilities
Root Control
08Ch
Root Status
090h
Device Capabilities 2
094h
One or more bits in this register are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Registers highlighted in gray are reserved or not implemented.
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Table 4-1. Classic PCI Configuration Register Map (continued)
REGISTER NAME
OFFSET
Device Status 2
Device Control 2
098h
Link Capabilities 2
09Ch
Link Status 2
Link Control 2
0A0h
Slot Capabilities 2
0A4h
Slot Status 2
Slot Control 2
0A8h
Reserved
Serial-bus slave address (1)
Serial-bus control and
status (1)
0ACh
Serial-bus word address (1)
GPIO data (1)
Serial-bus data (1)
0B0h
GPIO control (1)
0B4h
Reserved
0B8h–0BCh
TL Control and diagnostic register 0 (1)
0C0h
DLL Control and diagnostic register 1 (1)
0C4h
PHY Control and diagnostic register 2
(1)
0C8h
Reserved
0CCh
Subsystem access (1)
General control
0D0h
(1)
0D4h
Reserved
Clock run status (1)
Clock mask
Clock control
0D8h
Reserved
Arbiter time-out status
Arbiter request mask (1)
Arbiter control (1)
0DCh
Reserved
Serial IRQ mode control (1)
0E0h
Serial IRQ edge control (1)
Reserved
Serial IRQ status
Cache Timer Transfer Limit
PFA Request Limit
0E4h
0E8h
Cache Timer Upper Limit
Cache Timer Lower Limit
0ECh
Reserved
4.1
0F0h–0FCh
Vendor ID Register
This 16-bit read-only register contains the value 104Ch, which is the vendor ID assigned to Texas
Instruments.
PCI register offset:
00h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
4.2
15
0
104Ch
14
0
13
0
12
1
11
0
10
0
9
0
8
0
7
0
6
1
5
0
4
0
3
1
2
1
1
0
0
0
Device ID Register
This 16-bit read-only register contains the value 8231h, which is the device ID assigned by TI for the
bridge.
PCI register offset:
02h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
15
1
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8240h
14
0
13
0
12
0
11
0
10
0
9
1
8
0
7
0
6
1
5
0
4
0
3
0
2
0
1
0
Classic PCI Configuration Space
0
0
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Command Register
The command register controls how the bridge behaves on the PCI Express interface. See Table 4-2 for a
complete description of the register contents.
PCI register offset:
04h
Register type:
Read-only, Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-2. Command Register Description
BIT
15:11
FIELD NAME
ACCESS
DESCRIPTION
RSVD
R
Reserved. Returns 00000b when read.
10
INT_DISABLE
R
INTx disable. This bit enables device specific interrupts. Since the bridge does not
generate any internal interrupts, this bit is read-only 0b.
9
FBB_ENB
R
Fast back-to-back enable. The bridge does not generate fast back-to-back transactions;
therefore, this bit returns 0b when read.
8
SERR_ENB
RW
7
STEP_ENB
R
6
PERR_ENB
RW
SERR enable bit. When this bit is set, the bridge can signal fatal and nonfatal errors on the
PCI Express interface on behalf of SERR assertions detected on the PCI bus.
0 = Disable the reporting of nonfatal errors and fatal errors (default)
1 = Enable the reporting of nonfatal errors and fatal errors
Address/data stepping control. The bridge does not support address/data stepping, and
this bit is hardwired to 0b.
Controls the setting of bit 8 (DATAPAR) in the status register (offset 06h, see Section 4.4)
in response to a received poisoned TLP from PCI Express. A received poisoned TLP is
forwarded with bad parity to conventional PCI regardless of the setting of this bit.
0 = Disables the setting of the master data parity error bit (default)
1 = Enables the setting of the master data parity error bit
5
4
VGA_ENB
MWI_ENB
R
RW
VGA palette snoop enable. The bridge does not support VGA palette snooping; therefore,
this bit returns 0b when read.
Memory write and invalidate enable. When this bit is set, the bridge translates PCI
Express memory write requests into memory write and invalidate transactions on the PCI
interface.
0 = Disable the promotion to memory write and invalidate (default)
1 = Enable the promotion to memory write and invalidate
3
SPECIAL
R
Special cycle enable. The bridge does not respond to special cycle transactions; therefore,
this bit returns 0b when read.
Bus master enable. When this bit is set, the bridge is enabled to initiate transactions on
the PCI Express interface.
2
MASTER_ENB
RW
0 = PCI Express interface cannot initiate transactions. The bridge must disable the
response to memory and I/O transactions on the PCI interface (default).
1 = PCI Express interface can initiate transactions. The bridge can forward memory
and I/O transactions from PCI secondary interface to the PCI Express interface.
Memory space enable. Setting this bit enables the bridge to respond to memory
transactions on the PCI Express interface.
1
MEMORY_ENB
RW
0 = PCI Express receiver cannot process downstream memory transactions and must
respond with an unsupported request (default)
1 = PCI Express receiver can process downstream memory transactions. The bridge
can forward memory transactions to the PCI interface.
I/O space enable. Setting this bit enables the bridge to respond to I/O transactions on the
PCI Express interface.
0
IO_ENB
RW
0 = PCI Express receiver cannot process downstream I/O transactions and must
respond with an unsupported request (default)
1 = PCI Express receiver can process downstream I/O transactions. The bridge can
forward I/O transactions to the PCI interface.
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Status Register
The status register provides information about the PCI Express interface to the system. See Table 4-3 for
a complete description of the register contents.
PCI register offset:
06h
Register type:
Read-only, Read/Clear
Default value:
0010h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
1
3
0
2
0
1
0
0
0
Table 4-3. Status Register Description
BIT
15
FIELD NAME
PAR_ERR
ACCESS
RCU
DESCRIPTION
Detected parity error. This bit is set when the PCI Express interface receives a poisoned
TLP. This bit is set regardless of the state of bit 6 (PERR_ENB) in the command register
(offset 04h, see Section 4.3).
0 = No parity error detected
1 = Parity error detected
14
SYS_ERR
RCU
Signaled system error. This bit is set when the bridge sends an ERR_FATAL or
ERR_NONFATAL message and bit 8 (SERR_ENB) in the command register (offset 04h,
see Section 4.3) is set.
0 = No error signaled
1 = ERR_FATAL or ERR_NONFATAL signaled
Received master abort. This bit is set when the PCI Express interface of the bridge
receives a completion-with-unsupported-request status.
13
MABORT
RCU
0 = Unsupported request not received on the PCI Express interface
1 = Unsupported request received on the PCI Express interface
Received target abort. This bit is set when the PCI Express interface of the bridge receives
a completion-with-completer-abort status.
12
TABORT_REC
RCUT
0 = Completer abort not received on the PCI Express interface
1 = Completer abort received on the PCI Express interface
Signaled target abort. This bit is set when the PCI Express interface completes a request
with completer abort status.
11
TABORT_SIG
RCUT
0 = Completer abort not signaled on the PCI Express interface
1 = Completer abort signaled on the PCI Express interface
10:9
8
PCI_SPEED
DATAPAR
R
DEVSEL timing. These bits are read-only 00b, because they do not apply to PCI Express.
RCU
Master data parity error. This bit is set if bit 6 (PERR_ENB) in the command register (offset
04h, see Section 4.3) is set and the bridge receives a completion with data marked as
poisoned on the PCI Express interface or poisons a write request received on the PCI
Express interface.
0 = No uncorrectable data error detected on the primary interface
1 = Uncorrectable data error detected on the primary interface
7
FBB_CAP
R
Fast back-to-back capable. This bit does not have a meaningful context for a PCI Express
device and is hardwired to 0b.
6
RSVD
R
Reserved. Returns 0b when read.
5
66MHZ
R
66-MHz capable. This bit does not have a meaningful context for a PCI Express device and
is hardwired to 0b.
4
CAPLIST
R
Capabilities list. This bit returns 1b when read, indicating that the bridge supports additional
PCI capabilities.
3
INT_STATUS
R
Interrupt status. This bit reflects the interrupt status of the function. This bit is read-only 0b
since the bridge does not generate any interrupts internally.
RSVD
R
Reserved. Returns 000b when read.
2:0
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Class Code and Revision ID Register
This read-only register categorizes the base class, subclass, and programming interface of the bridge. The
base class is 06h, identifying the device as a bridge. The subclass is 04h, identifying the function as a
PCI-to-PCI bridge, and the programming interface is 00h. Furthermore, the TI device revision is indicated
in the lower byte (03h). See Table 4-4 for a complete description of the register contents.
PCI register offset:
08h
Register type:
Read-only
Default value:
0604 0000
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
1
25
1
24
0
23
0
22
0
21
0
20
0
19
0
18
1
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-4. Class Code and Revision ID Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
31:24
BASECLASS
R
Base class. This field returns 06h when read, which classifies the function as a bridge device.
23:16
SUBCLASS
R
Subclass. This field returns 04h when read, which classifies the function as a PCI-to-PCI bridge.
15:8
PGMIF
R
Programming interface. This field returns 00h when read.
7:0
CHIPREV
R
Silicon revision. This field returns the silicon revision of the function.
4.6
Cache Line Size Register
This register is used to determine when a downstream write is memory write (MW) or memory write
invalidate (MWI).
A posted write TLP will normally be sent as a MW on the PCI bus. It will be sent as a MWI when the
following conditions are met:
• Cacheline size register has a value that is a power of two (1, 2, 4, 8, 16, 32, 64, or 128)
• The write starts on a cacheline boundary
• The write is one or more cachelines in length
• First and last bytes have all lanes enabled
• Memory write invalidates are enabled
PCI register offset:
0Ch
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
52
7
0
00h
6
0
Classic PCI Configuration Space
5
0
4
0
3
0
2
0
1
0
0
0
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4.7
SCPS212B – MAY 2009 – REVISED JULY 2009
Primary Latency Timer Register
This read-only register has no meaningful context for a PCI Express device and returns 00h when read.
PCI register offset:
0Dh
Register type:
Read only
Default value:
00h
BIT NUMBER
RESET STATE
4.8
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Header Type Register
This read-only register indicates that this function has a type one PCI header. Bit 7 of this register is 0b
indicating that the bridge is a single-function device.
PCI register offset:
0Eh
Register type:
Read only
Default value:
01h
BIT NUMBER
RESET STATE
4.9
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
BIST Register
Since the bridge does not support a built-in self test (BIST), this read-only register returns the value of 00h
when read.
PCI register offset:
0Fh
Register type:
Read only
Default value:
BIT NUMBER
RESET STATE
00h
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.10 Device Control Base Address Register
This register programs the memory base address that accesses the device control registers. By default,
this register is read only. If bit 5 of the Control and Diagnostic Register 2 (see Section 4.63) is set, then
the bits 31:12 of this register become read/write. See Table 4-5 for a complete description of the register
contents.
PCI register offset:
10h
Register type:
Read-only, Read/Write
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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Table 4-5. Device Control Base Address Register Description
BIT
FIELD NAME
31:12
ADDRESS
11:4
ACCESS
R or RW
DESCRIPTION
Memory Address. The memory address field for XIO2001 uses 20 read/write bits indicating
that 4096 bytes of memory space are required. While less than this is actually used, typical
systems will allocate this space on a 4K boundary. If the BAR0_EN bit (bit 5 at C8h) is ‘0’,
then these bits are read-only and return zeros when read. If the BAR0_EN bit is ‘1’, then
these bits are read/write.
RSVD
R
Reserved. These bits are read-only and return 00h when read.
3
PRE_FETCH
R
Prefetchable. This bit is read-only 0b indicating that this memory window is not prefetchable.
2:1
MEM_TYPE
R
Memory type. This field is read-only 00b indicating that this window can be located anywhere
in the 32-bit address space.
MEM_IND
R
Memory space indicator. This field returns 0b indicating that memory space is used.
0
4.11 Primary Bus Number Register
This read/write register specifies the bus number of the PCI bus segment that the PCI Express interface is
connected to.
PCI register offset:
18h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
7
0
00h
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.12 Secondary Bus Number Register
This read/write register specifies the bus number of the PCI bus segment that the PCI interface is
connected to. The bridge uses this register to determine how to respond to a type 1 configuration
transaction.
PCI register offset:
19h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
7
0
00h
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.13 Subordinate Bus Number Register
This read/write register specifies the bus number of the highest number PCI bus segment that is
downstream of the bridge. The bridge uses this register to determine how to respond to a type 1
configuration transaction.
PCI register offset:
1Ah
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
54
7
0
6
0
Classic PCI Configuration Space
5
0
4
0
3
0
2
0
1
0
0
0
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4.14 Secondary Latency Timer Register
This read/write register specifies the secondary bus latency timer for the bridge, in units of PCI clock
cycles.
PCI register offset:
1Bh
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.15 I/O Base Register
This read/write register specifies the lower limit of the I/O addresses that the bridge forwards downstream.
See Table 4-6 for a complete description of the register contents.
PCI register offset:
1Ch
Register type:
Read-only, Read/Write
Default value:
01h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
Table 4-6. I/O Base Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
I/O base. Defines the bottom address of the I/O address range that determines when to forward I/O
transactions from one interface to the other. These bits correspond to address bits [15:12] in the I/O
address. The lower 12 bits are assumed to be 000h. The 16 bits corresponding to address bits
[31:16] of the I/O address are defined in the I/O base upper 16 bits register (offset 30h, see
Section 4.24).
7:4
IOBASE
RW
3:0
IOTYPE
R
I/O type. This field is read-only 1h indicating that the bridge supports 32-bit I/O addressing.
4.16 I/O Limit Register
This read/write register specifies the upper limit of the I/O addresses that the bridge forwards downstream.
See Table 4-7 for a complete description of the register contents.
PCI register offset:
1Dh
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
7
0
01h
6
0
5
0
4
0
3
0
2
0
1
0
0
1
Table 4-7. I/O Limit Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
I/O limit. Defines the top address of the I/O address range that determines when to forward I/O
transactions from one interface to the other. These bits correspond to address bits [15:12] in the I/O
address. The lower 12 bits are assumed to be FFFh. The 16 bits corresponding to address bits
[31:16] of the I/O address are defined in the I/O limit upper 16 bits register (offset 32h, see
Section 4.25).
7:4
IOLIMIT
RW
3:0
IOTYPE
R
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I/O type. This field is read-only 1h indicating that the bridge supports 32-bit I/O addressing.
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4.17 Secondary Status Register
The secondary status register provides information about the PCI bus interface. See Table 4-8 for a
complete description of the register contents.
PCI register offset:
1Eh
Register type:
Read-only, Read/Clear
Default value:
02X0h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
1
8
0
7
1
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-8. Secondary Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
Detected parity error. This bit reports the detection of an uncorrectable address, attribute, or data
error by the bridge on its internal PCI bus secondary interface. This bit must be set when any of the
following three conditions are true:
• The bridge detects an uncorrectable address or attribute error as a potential target.
• The bridge detects an uncorrectable data error when it is the target of a write transaction.
15
PAR_ERR
• The bridge detects an uncorrectable data error when it is the master of a read transaction
(immediate read data).
RCU
The bit is set irrespective of the state of bit 0 (PERR_EN) in the bridge control register at offset 3Eh
(see Section 4.29).
0 = Uncorrectable address, attribute, or data error not detected on secondary interface
1 = Uncorrectable address, attribute, or data error detected on secondary interface
Received system error. This bit is set when the bridge detects an SERR assertion.
14
13
SYS_ERR
MABORT
RCU
RCU
0 = No error asserted on the PCI interface
1 = SERR asserted on the PCI interface
Received master abort. This bit is set when the PCI interface of the bridge reports the detection of a
master abort termination by the bridge when it is the master of a transaction on its secondary
interface.
0 = Master abort not received on the PCI interface
1 = Master abort received on the PCI interface
Received target abort. This bit is set when the PCI interface of the bridge receives a target abort.
12
11
TABORT_REC
TABORT_SIG
10:9 PCI_SPEED
8
DATAPAR
RCU
RCU
R
RCU
0 = Target abort not received on the PCI interface
1 = Target abort received on the PCI interface
Signaled target abort. This bit reports the signaling of a target abort termination by the bridge when it
responds as the target of a transaction on its secondary interface.
0 = Target abort not signaled on the PCI interface
1 = Target abort signaled on the PCI interface
DEVSEL timing. These bits are 01b indicating that this is a medium speed decoding device.
Master data parity error. This bit is set if the bridge is the bus master of the transaction on the PCI
bus, bit 0 (PERR_EN) in the bridge control register (offset 3Eh see Section 4.29) is set, and the
bridge either asserts PERR on a read transaction or detects PERR asserted on a write transaction.
0 = No data parity error detected on the PCI interface
1 = Data parity error detected on the PCI Interface
7
FBB_CAP
R
Fast back-to-back capable. This bit returns a 1b when read indicating that the secondary PCI
interface of bridge supports fast back-to-back transactions.
6
RSVD
R
Reserved. Returns 0b when read.
5
66MHZ
R
66-MHz capable. The bridge operates at a PCI bus CLK frequency of 66 MHz; therefore, this bit
always returns a 1b.
4:0
RSVD
R
Reserved. Returns 00000b when read.
56
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4.18 Memory Base Register
This read/write register specifies the lower limit of the memory addresses that the bridge forwards
downstream. See Table 4-9 for a complete description of the register contents.
PCI register offset:
20h
Register type:
Read-only, Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-9. Memory Base Register Description
BIT
FIELD NAME
15:4
MEMBASE
3:0
RSVD
ACCESS
DESCRIPTION
RW
Memory base. Defines the lowest address of the memory address range that determines when to
forward memory transactions from one interface to the other. These bits correspond to address bits
[31:20] in the memory address. The lower 20 bits are assumed to be 00000h.
R
Reserved. Returns 0h when read.
4.19 Memory Limit Register
This read/write register specifies the upper limit of the memory addresses that the bridge forwards
downstream. See Table 4-10 for a complete description of the register contents.
PCI register offset:
22h
Register type:
Read-only, Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-10. Memory Limit Register Description
BIT
FIELD NAME
15:4
MEMLIMIT
3:0
RSVD
ACCESS
DESCRIPTION
RW
Memory limit. Defines the highest address of the memory address range that determines when to
forward memory transactions from one interface to the other. These bits correspond to address bits
[31:20] in the memory address. The lower 20 bits are assumed to be FFFFFh.
R
Reserved. Returns 0h when read.
4.20 Prefetchable Memory Base Register
This read/write register specifies the lower limit of the prefetchable memory addresses that the bridge
forwards downstream. See Table 4-11 for a complete description of the register contents.
PCI register offset:
24h
Register type:
Read-only, Read/Write
Default value:
0001h
BIT NUMBER
RESET STATE
15
0
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14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
Classic PCI Configuration Space
0
1
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Table 4-11. Prefetchable Memory Base Register Description
BIT
FIELD NAME
15:4
PREBASE
3:0
64BIT
ACCESS
DESCRIPTION
RW
Prefetchable memory base. Defines the lowest address of the prefetchable memory address range
that determines when to forward memory transactions from one interface to the other. These bits
correspond to address bits [31:20] in the memory address. The lower 20 bits are assumed to be
00000h. The prefetchable base upper 32 bits register (offset 28h, see Section 4.22) specifies the bit
[63:32] of the 64-bit prefetchable memory address.
64-bit memory indicator. These read-only bits indicate that 64-bit addressing is supported for this
memory window.
R
4.21 Prefetchable Memory Limit Register
This read/write register specifies the upper limit of the prefetchable memory addresses that the bridge
forwards downstream. See Table 4-12 for a complete description of the register contents.
PCI register offset:
26h
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0001h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
Table 4-12. Prefetchable Memory Limit Register Description
BIT
FIELD NAME
15:4
PRELIMIT
3:0
64BIT
ACCESS
DESCRIPTION
RW
Prefetchable memory limit. Defines the highest address of the prefetchable memory address range
that determines when to forward memory transactions from one interface to the other. These bits
correspond to address bits [31:20] in the memory address. The lower 20 bits are assumed to be
FFFFFh. The prefetchable limit upper 32 bits register (offset 2Ch, see Section 4.23) specifies the bit
[63:32] of the 64-bit prefetchable memory address.
64-bit memory indicator. These read-only bits indicate that 64-bit addressing is supported for this
memory window.
R
4.22 Prefetchable Base Upper 32-Bit Register
This read/write register specifies the upper 32 bits of the prefetchable memory base register. See
Table 4-13 for a complete description of the register contents.
PCI register offset:
28h
Register type:
Read/Write
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-13. Prefetchable Base Upper 32-Bit Register Description
BIT
31:0
58
FIELD NAME
PREBASE
ACCESS
RW
DESCRIPTION
Prefetchable memory base upper 32 bits. Defines the upper 32 bits of the lowest address of the
prefetchable memory address range that determines when to forward memory transactions
downstream.
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4.23 Prefetchable Limit Upper 32-Bit Register
This read/write register specifies the upper 32 bits of the prefetchable memory limit register. See
Table 4-14 for a complete description of the register contents.
PCI register offset:
2Ch
Register type:
Read/Write
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-14. Prefetchable Limit Upper 32-Bit Register Description
BIT
31:0
FIELD NAME
ACCESS
PRELIMIT
DESCRIPTION
Prefetchable memory limit upper 32 bits. Defines the upper 32 bits of the highest address of the
prefetchable memory address range that determines when to forward memory transactions
downstream.
RW
4.24 I/O Base Upper 16-Bit Register
This read/write register specifies the upper 16 bits of the I/O base register. See Table 4-15 for a complete
description of the register contents.
PCI register offset:
30h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-15. I/O Base Upper 16-Bit Register Description
BIT
15:0
FIELD NAME
ACCESS
IOBASE
DESCRIPTION
I/O base upper 16 bits. Defines the upper 16 bits of the lowest address of the I/O address range
that determines when to forward I/O transactions downstream. These bits correspond to address
bits [31:20] in the I/O address. The lower 20 bits are assumed to be 00000h.
RW
4.25 I/O Limit Upper 16-Bit Register
This read/write register specifies the upper 16 bits of the I/O limit register. See Table 4-16 for a complete
description of the register contents.
PCI register offset:
32h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
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0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
Classic PCI Configuration Space
0
0
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XIO2001 PCI Express™ to PCI Bus Translation Bridge
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Table 4-16. I/O Limit Upper 16-Bit Register Description
BIT
FIELD NAME
15:0
IOLIMIT
ACCESS
DESCRIPTION
I/O limit upper 16 bits. Defines the upper 16 bits of the top address of the I/O address range that
determines when to forward I/O transactions downstream. These bits correspond to address bits
[31:20] in the I/O address. The lower 20 bits are assumed to be FFFFFh.
RW
4.26 Capabilities Pointer Register
This read-only register provides a pointer into the PCI configuration header where the PCI power
management block resides. Since the PCI power management registers begin at 40h, this register is
hardwired to 40h.
PCI register offset:
34h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
7
0
40h
6
1
5
0
4
0
3
0
2
0
1
0
0
0
4.27 Interrupt Line Register
This read/write register is programmed by the system and indicates to the software which interrupt line the
bridge has assigned to it. The default value of this register is FFh, indicating that an interrupt line has not
yet been assigned to the function. Since the bridge does not generate interrupts internally, this register is
a scratch pad register.
PCI register offset:
3Ch
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
7
1
FFh
6
1
5
1
4
1
3
1
2
1
1
1
0
1
4.28 Interrupt Pin Register
The interrupt pin register is read-only 00h indicating that the bridge does not generate internal interrupts.
While the bridge does not generate internal interrupts, it does forward interrupts from the secondary
interface to the primary interface.
PCI register offset:
3Dh
Register type:
Read-only
Default value:
00h
BIT NUMBER
RESET STATE
60
7
0
6
0
Classic PCI Configuration Space
5
0
4
0
3
0
2
0
1
0
0
0
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4.29
SCPS212B – MAY 2009 – REVISED JULY 2009
Bridge Control Register
The bridge control register provides extensions to the command register that are specific to a bridge. See
Table 4-17 for a complete description of the register contents.
PCI register offset:
3Eh
Register type:
Read-only, Read/Write, Read/Clear
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-17. Bridge Control Register Description
BIT
15:12
11
FIELD NAME
RSVD
DTSERR
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 0h when read.
Discard timer SERR enable. Applies only in conventional PCI mode. This bit enables the
bridge to generate either an ERR_NONFATAL (by default) or ERR_FATAL transaction on
the primary interface when the secondary discard timer expires and a delayed transaction
is discarded from a queue in the bridge. The severity is selectable only if advanced error
reporting is supported.
0 = Do not generate ERR_NONFATAL or ERR_FATAL on the primary interface as a
result of the expiration of the secondary discard timer. Note that an error message
can still be sent if advanced error reporting is supported and bit 10
(DISCARD_TIMER_MASK) in the secondary uncorrectable error mask register
(offset 130h, see Section 5.11) is clear (default).
1 = Generate ERR_NONFATAL or ERR_FATAL on the primary interface if the
secondary discard timer expires and a delayed transaction is discarded from a
queue in the bridges.
10
DTSTATUS
RCU
Discard timer status. This bit indicates if a discard timer expires and a delayed transaction
is discarded.
0 = No discard timer error
1 = Discard timer error
9
SEC_DT
RW
Selects the number of PCI clocks that the bridge waits for a master on the secondary
interface to repeat a delayed transaction request. The counter starts once the delayed
completion (the completion of the delayed transaction on the primary interface) has
reached the head of the downstream queue of the bridge (i.e., all ordering requirements
have been satisfied and the bridge is ready to complete the delayed transaction with the
initiating master on the secondary bus). If the master does not repeat the transaction
before the counter expires, then the bridge deletes the delayed transaction from its queue
and sets the discard timer status bit.
0 = The secondary discard timer counts 215 PCI clock cycles (default)
1 = The secondary discard timer counts 210 PCI clock cycles
8
PRI_DEC
R
7
FBB_EN
RW
Primary discard timer. This bit has no meaning in PCI Express and is hardwired to 0b.
Fast back-to-back enable. This bit allows software to enable fast back-to-back
transactions on the secondary PCI interface.
0 = Fast back-to-back transactions are disabled (default)
1 = Secondary interface fast back-to-back transactions are enabled
6
SRST
RW
Secondary bus reset. This bit is set when software wishes to reset all devices
downstream of the bridge. Setting this bit causes the PRST signal on the secondary
interface to be asserted.
0 = Secondary interface is not in reset state (default)
1 = Secondary interface is in the reset state
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Table 4-17. Bridge Control Register Description (continued)
BIT
5
FIELD NAME
MAM
ACCESS
RW
DESCRIPTION
Master abort mode. This bit controls the behavior of the bridge when it receives a master
abort or an unsupported request.
0 = Do not report master aborts. Returns FFFF FFFFh on reads and discard data on
writes (default)
1 = Respond with an unsupported request on PCI Express when a master abort is
received on PCI. Respond with target abort on PCI when an unsupported request
completion on PCI Express is received. This bit also enables error signaling on
master abort conditions on posted writes.
4
VGA16
RW
VGA 16-bit decode. This bit enables the bridge to provide full 16-bit decoding for VGA I/O
addresses. This bit only has meaning if the VGA enable bit is set.
0 = Ignore address bits [15:10] when decoding VGA I/O addresses (default)
1 = Decode address bits [15:10] when decoding VGA I/O addresses
3
VGA
RW
VGA enable. This bit modifies the response by the bridge to VGA compatible addresses.
If this bit is set, then the bridge decodes and forwards the following accesses on the
primary interface to the secondary interface (and, conversely, block the forwarding of
these addresses from the secondary to primary interface):
• Memory accesses in the range 000A 0000h to 000B FFFFh
• I/O addresses in the first 64 KB of the I/O address space (address bits [31:16] are
0000h) and where address bits [9:0] are in the range of 3B0h to 3BBh or 3C0h to
3DFh (inclusive of ISA address aliases – address bits [15:10] may possess any
value and are not used in the decoding)
If this bit is set, then forwarding of VGA addresses is independent of the value of bit 2
(ISA), the I/O address and memory address ranges defined by the I/O base and limit
registers, the memory base and limit registers, and the prefetchable memory base and
limit registers of the bridge. The forwarding of VGA addresses is qualified by bits 0
(IO_ENB) and 1 (MEMORY_ENB) in the command register (offset 04h, see Section 4.3).
0 = Do not forward VGA compatible memory and I/O addresses from the primary to
secondary interface (addresses defined above) unless they are enabled for
forwarding by the defined I/O and memory address ranges (default).
1 = Forward VGA compatible memory and I/O addresses (addresses defined above)
from the primary interface to the secondary interface (if the I/O enable and memory
enable bits are set) independent of the I/O and memory address ranges and
independent of the ISA enable bit.
2
ISA
RW
ISA enable. This bit modifies the response by the bridge to ISA I/O addresses. This
applies only to I/O addresses that are enabled by the I/O base and I/O limit registers and
are in the first 64 KB of PCI I/O address space (0000 0000h to 0000 FFFFh). If this bit is
set, then the bridge blocks any forwarding from primary to secondary of I/O transactions
addressing the last 768 bytes in each 1-KB block. In the opposite direction (secondary to
primary), I/O transactions are forwarded if they address the last 768 bytes in each 1K
block.
0 = Forward downstream all I/O addresses in the address range defined by the I/O
base and I/O limit registers (default)
1 = Forward upstream ISA I/O addresses in the address range defined by the I/O base
and I/O limit registers that are in the first 64 KB of PCI I/O address space (top 768
bytes of each 1-KB block)
1
SERR_EN
RW
SERR enable. This bit controls forwarding of system error events from the secondary
interface to the primary interface. The bridge forwards system error events when:
• This bit is set
• Bit 8 (SERR_ENB) in the command register (offset 04h, see Section 4.3) is set
• SERR is asserted on the secondary interface
0 = Disable the forwarding of system error events (default)
1 = Enable the forwarding of system error events
62
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Table 4-17. Bridge Control Register Description (continued)
BIT
0
FIELD NAME
ACCESS
DESCRIPTION
RW
Parity error response enable. Controls the bridge's response to data, uncorrectable
address, and attribute errors on the secondary interface. Also, the bridge always forwards
data with poisoning, from conventional PCI to PCI Express on an uncorrectable
conventional PCI data error, regardless of the setting of this bit.
PERR_EN
0 = Ignore uncorrectable address, attribute, and data errors on the secondary interface
(default)
1 = Enable uncorrectable address, attribute, and data error detection and reporting on
the secondary interface
4.30 Capability ID Register
This read-only register identifies the linked list item as the register for Subsystem ID and Subsystem
Vendor ID capabilities. The register returns 0Dh when read.
PCI register offset:
40h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
7
0
0Dh
6
0
5
0
4
0
3
1
2
1
1
0
0
1
4.31 Next Item Pointer Register
The contents of this read-only register indicate the next item in the linked list of capabilities for the bridge.
This register reads 48h pointing to the PCI Power Management Capabilities registers.
PCI register offset:
41h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
7
0
48h
6
1
5
0
4
0
3
1
2
0
1
0
0
0
4.32 Subsystem Vendor ID Register
This register, used for system and option card identification purposes, may be required for certain
operating systems. This read-only register is initialized through the EEPROM and can be written through
the subsystem alias register. This register is reset by a PCI Express reset (PERST), a GRST, or the
internally-generated power-on reset.
PCI register offset:
44h
Register type:
Read-only
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
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14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
Classic PCI Configuration Space
0
0
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4.33 Subsystem ID Register
This register, used for system and option card identification purposes, may be required for certain
operating systems. This read-only register is initialized through the EEPROM and can be written through
the subsystem alias register. This register is reset by a PCI Express reset (PERST), a GRST, or the
internally-generated power-on reset.
PCI register offset:
46h
Register type:
Read-only
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.34 Capability ID Register
This read-only register identifies the linked list item as the register for PCI Power Management ID
Capabilities. The register returns 01h when read.
PCI register offset:
48h
Register type:
Read-only
Default value:
01h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
4.35 Next Item Pointer Register
The contents of this read-only register indicate the next item in the linked list of capabilities for the bridge.
This register reads 50h pointing to the MSI Capabilities registers.
PCI register offset:
49h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
7
0
50h
6
1
5
0
4
1
3
0
2
0
1
0
0
0
4.36 Power Management Capabilities Register
This read-only register indicates the capabilities of the bridge related to PCI power management. See
Table 4-18 for a complete description of the register contents.
PCI register offset:
4Ah
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
64
15
0
0603h
14
0
Classic PCI Configuration Space
13
0
12
0
11
0
10
1
9
1
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
1
0
1
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Table 4-18. Power Management Capabilities Register Description
BIT
FIELD NAME
ACCESS
15:11
PME_SUPPORT
R
PME support. This 5-bit field indicates the power states from which the bridge may assert
PME. Because the bridge never generates a PME except on a behalf of a secondary
device, this field is read-only and returns 00000b.
10
D2_SUPPORT
R
This bit returns a 1b when read, indicating that the function supports the D2 device power
state.
9
D1_SUPPORT
R
This bit returns a 1b when read, indicating that the function supports the D1 device power
state.
AUX_CURRENT
R
3.3 VAUX auxiliary current requirements. This field returns 000b since the bridge does not
generate PME from D3cold.
5
DSI
R
Device specific initialization. This bit returns 0b when read, indicating that the bridge does
not require special initialization beyond the standard PCI configuration header before a
generic class driver is able to use it.
4
RSVD
R
Reserved. Returns 0b when read.
3
PME_CLK
R
PME clock. This bit returns 0b indicating that the PCI clock is not needed to generate PME.
PM_VERSION
R
Power management version. If bit 26 (PCI_PM_VERSION_CTRL) in the general control
register (offset D4h, see Section 4.65) is 0b, then this field returns 010b indicating revision
1.1 compatibility. If PCI_PM_VERSION_CTRL is 1b, then this field returns 011b indicating
revision 1.2 compatibility.
8:6
2:0
DESCRIPTION
4.37 Power Management Control/Status Register
This register determines and changes the current power state of the bridge. No internal reset is generated
when transitioning from the D3hot state to the D0 state. See Table 4-19 for a complete description of the
register contents.
PCI register offset:
4Ch
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0008h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
1
2
0
1
0
0
0
Table 4-19. Power Management Control/Status Register Description
BIT
15
FIELD NAME
ACCESS
DESCRIPTION
PME_STAT
R
PME status. This bit is read-only and returns 0b when read.
14:13
DATA_SCALE
R
Data scale. This 2-bit field returns 00b when read since the bridge does not use the data
register.
12:9
DATA_SEL
R
Data select. This 4-bit field returns 0h when read since the bridge does not use the data
register.
8
7:4
PME_EN
RW
PME enable. This bit has no function and acts as scratchpad space. The default value for
this bit is 0b.
RSVD
R
Reserved. Returns 0h when read.
3
NO_SOFT_RESET
R
No soft reset. If bit 26 (PCI_PM_VERSION_CTRL) in the general control register (offset
D4h, see Section 4.65) is 0b, then this bit returns 0b for compatibility with version 1.1 of the
PCI Power Management Specification. If PCI_PM_VERSION_CTRL is 1b, then this bit
returns 1b indicating that no internal reset is generated and the device retains its
configuration context when transitioning from the D3hot state to the D0 state.
2
RSVD
R
Reserved. Returns 0b when read.
1:0
PWR_STATE
RW
Power state. This 2-bit field determines the current power state of the function and sets the
function into a new power state. This field is encoded as follows:
00 = D0 (default)
01 = D1
10 = D2
11 = D3hot
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4.38 Power Management Bridge Support Extension Register
This read-only register indicates to host software what the state of the secondary bus will be when the
bridge is placed in D3. See Table 4-20 for a complete description of the register contents.
PCI register offset:
4Eh
Register type:
Read-only
Default value:
40h
BIT NUMBER
RESET STATE
7
0
6
1
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-20. PM Bridge Support Extension Register Description
BIT
7
FIELD NAME
ACCESS
DESCRIPTION
R
Bus power/clock control enable. This bit indicates to the host software if the bus secondary
clocks are stopped when the bridge is placed in D3. The state of the BPCC bit is
controlled by bit 11 (BPCC_E) in the general control register (offset D4h, see
Section 4.65).
BPCC
0 = The secondary bus clocks are not stopped in D3
1 = The secondary bus clocks are stopped in D3
6
5:0
BSTATE
R
B2/B3 support. This bit is read-only 1b indicating that the bus state in D3 is B2.
RSVD
R
Reserved. Returns 00 0000b when read.
4.39 Power Management Data Register
The read-only register is not applicable to the bridge and returns 00h when read.
PCI register offset:
4Fh
Register type:
Read-only
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.40 MSI Capability ID Register
This read-only register identifies the linked list item as the register for message signaled interrupts
capabilities. The register returns 05h when read.
PCI register offset:
50h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
66
7
0
05h
6
0
Classic PCI Configuration Space
5
0
4
0
3
0
2
1
1
0
0
1
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4.41 Next Item Pointer Register
The contents of this read-only register indicate the next item in the linked list of capabilities for the bridge.
This register reads 70h pointing to the subsystem ID capabilities registers.
PCI register offset:
51h
Register type:
Read-only
Default value:
70h
BIT NUMBER
RESET STATE
7
0
6
1
5
1
4
1
3
0
2
0
1
0
0
0
4.42 MSI Message Control Register
This register controls the sending of MSI messages. See Table 4-21 for a complete description of the
register contents.
PCI register offset:
52h
Register type:
Read-only, Read/Write
Default value:
0088h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
1
6
0
5
0
4
0
3
1
2
0
1
0
0
0
Table 4-21. MSI Message Control Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
15:8
RSVD
R
Reserved. Returns 00h when read.
7
64CAP
R
64-bit message capability. This bit is read-only 1b indicating that the bridge supports 64-bit
MSI message addressing.
6:4
MM_EN
RW
Multiple message enable. This bit indicates the number of distinct messages that the
bridge is allowed to generate.
000
001
010
011
100
101
110
111
3:1
MM_CAP
R
0
MSI_EN
RW
= 1 message (default)
= 2 messages
= 4 messages
= 8 messages
= 16 messages
= Reserved
= Reserved
= Reserved
Multiple message capabilities. This field indicates the number of distinct messages that
bridge is capable of generating. This field is read-only 100b indicating that the bridge can
signal 1 interrupt for each IRQ supported on the serial IRQ stream up to a maximum of 16
unique interrupts.
MSI enable. This bit enables MSI interrupt signaling. MSI signaling must be enabled by
software for the bridge to signal that a serial IRQ has been detected.
0 = MSI signaling is prohibited (default)
1 = MSI signaling is enabled
4.43 MSI Message Lower Address Register
This register contains the lower 32 bits of the address that a MSI message writes to when a serial IRQ is
detected. See Table 4-22 for a complete description of the register contents.
PCI register offset:
54h
Register type:
Read-only, Read/Write
Default value:
0000 0000h
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BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-22. MSI Message Lower Address Register Description
BIT
FIELD NAME
31:2
ADDRESS
1:0
RSVD
ACCESS
DESCRIPTION
RW
System specified message address
R
Reserved. Returns 00b when read.
4.44 MSI Message Upper Address Register
This register contains the upper 32 bits of the address that a MSI message writes to when a serial IRQ is
detected. If this register contains 0000 0000h, then 32-bit addressing is used; otherwise, 64-bit addressing
is used.
PCI register offset:
58h
Register type:
Read/Write
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4.45 MSI Message Data Register
This register contains the data that software programmed the bridge to send when it send a MSI message.
See Table 4-23 for a complete description of the register contents.
PCI register offset:
5Ch
Register type:
Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-23. MSI Message Data Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
15:4
MSG
RW
System specific message. This field contains the portion of the message that the bridge
forwards unmodified.
3:0
MSG_NUM
RW
Message number. This portion of the message field may be modified to contain the
message number is multiple messages are enable. The number of bits that are modifiable
depends on the number of messages enabled in the message control register.
1 message = No message data bits can be modified (default)
2 messages = Bit 0 can be modified
4 messages = Bits 1:0 can be modified
8 messages = Bits 2:0 can be modified
16 messages = Bits 3:0 can be modified
68
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4.46
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PCI Express Capability ID Register
This read-only register identifies the linked list item as the register for subsystem ID and subsystem
vendor ID capabilities. The register returns 10h when read.
PCI register offset:
70h
Register type:
Read-only
Default value:
10h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
1
3
0
2
0
1
0
0
0
4.47 Next Item Pointer Register
The contents of this read-only register indicate the next item in the linked list of capabilities for the bridge.
This register reads 00h, indicating no additional capabilities are supported.
PCI register offset:
71h
Register type:
Read-only
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.48 PCI Express Capabilities Register
This read-only register indicates the capabilities of the bridge related to PCI Express. See Table 4-24 for a
complete description of the register contents.
PCI register offset:
72h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
15
0
0072h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
1
5
1
4
1
3
0
2
0
1
0
0
1
Table 4-24. PCI Express Capabilities Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
15:14
RSVD
R
Reserved. Returns 00b when read.
13:9
INT_NUM
R
Interrupt message number. This field is used for MSI support and is implemented as
read-only 00000b in the bridge.
SLOT
R
Slot implemented. This bit is not valid for the bridge and is read-only 0b.
7:4
8
DEV_TYPE
R
Device/port type. This read-only field returns 0111b indicating that the device is a PCI
Express-to-PCI bridge.
3:0
VERSION
R
Capability version. This field returns 2h indicating revision 2 of the PCI Express capability.
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4.49 Device Capabilities Register
The device capabilities register indicates the device specific capabilities of the bridge. See Table 4-25 for
a complete description of the register contents.
PCI register offset:
74h
Register type:
Read-only
Default value:
0000 8D82
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
1
0
0
0
1
1
0
1
1
0
0
0
0
0
1
0
Table 4-25. Device Capabilities Register Description
BIT
FIELD NAME
ACCESS
31:28
RSVD
R
27:26
CSPLS
RU
DESCRIPTION
Reserved. Returns 0h when read.
Captured slot power limit scale. The value in this field is programmed by the host by issuing a
Set_Slot_Power_Limit message. When a Set_Slot_Power_Limit message is received, bits 9:8
are written to this field. The value in this field specifies the scale used for the slot power limit.
00 =
01 =
10 =
11 =
25:18
CSPLV
RU
17:16
RSVD
R
Reserved. Return 00b when read.
15
RBER
R
Role based error reporting. This bit is hardwired to 1 indicating that this bridge supports Role
Based Error Reporting.
14
PIP
R
Power indicator present. This bit is hardwired to 0b indicating that a power indicator is not
implemented.
13
AIP
R
Attention indicator present. This bit is hardwired to 0b indicating that an attention indicator is not
implemented.
12
ABP
R
Attention button present. This bit is hardwired to 0b indicating that an attention button is not
implemented.
Captured slot power limit value. The value in this field is programmed by the host by issuing a
Set_Slot_Power_Limit message. When a Set_Slot_Power_Limit message is received, bits 7:0
are written to this field. The value in this field in combination with the slot power limit scale value
(bits 27:26) specifies the upper limit of power supplied to the slot. The power limit is calculated
by multiplying the value in this field by the value in the slot power limit scale field.
11:9
EP_L1_LAT
RU
Endpoint L1 acceptable latency. This field indicates the maximum acceptable latency for a
transition from L1 to L0 state. This field can be programmed by writing to the L1_LATENCY
field (bits 15:13) in the general control register (offset D4h, see Section 4.65). The default value
for this field is 110b which indicates a range from 32µs to 64µs. This field cannot be
programmed to be less than the latency for the PHY to exit the L1 state.
8:6
EP_L0S_LAT
RU
Endpoint L0s acceptable latency. This field indicates the maximum acceptable latency for a
transition from L0s to L0 state. This field can be programmed by writing to the L0s_LATENCY
field (bits 18:16) in the general control register (offset D4h, see Section 4.65). The default value
for this field is 110b which indicates a range from 2µs to 4µs. This field cannot be programmed
to be less than the latency for the PHY to exit the L0s state.
5
70
1.0x
0.1x
0.01x
0.001x
ETFS
R
Extended tag field supported. This field indicates the size of the tag field not supported.
4:3
PFS
R
Phantom functions supported. This field is read-only 00b indicating that function numbers are
not used for phantom functions.
2:0
MPSS
R
Maximum payload size supported. This field indicates the maximum payload size that the
device can support for TLPs. This field is encoded as 010b indicating the maximum payload
size for a TLP is 512 bytes.
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4.50 Device Control Register
The device control register controls PCI Express device specific parameters. See Table 4-26 for a
complete description of the register contents.
PCI register offset:
78h
Register type:
Read-only, Read/Write
Default value:
2000h
BIT NUMBER
RESET STATE
15
0
14
0
13
1
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-26. Device Control Register Description
BIT
15
14:12
FIELD NAME
ACCESS
DESCRIPTION
CFG_RTRY_ENB
RW
Configuration retry status enable. When this read/write bit is set to 1b, the bridge returns a
completion with completion retry status on PCI Express if a configuration transaction
forwarded to the secondary interface did not complete within the implementation specific
time-out period. When this bit is set to 0b, the bridge does not generate completions with
completion retry status on behalf of configuration transactions. The default value of this bit is
0b.
MRRS
RW
Maximum read request size. This field is programmed by host software to set the maximum
size of a read request that the bridge can generate. The bridge uses this field to determine
how much data to fetch on a read request. This field is encoded as:
000
001
010
011
100
101
110
111
11
ENS
10
APPE
R
RW
= 128B
= 256B
= 512B (default)
= 1024B
= 2048B
= 4096B
= Reserved
= Reserved
Enable no snoop. This bit is hardwired to 0 since this device never sets the No Snoop attribute
in transactions that it initiates.
Auxiliary power PM enable. This bit has no effect in the bridge.
0 = AUX power is disabled (default)
1 = AUX power is enabled
9
PFE
R
Phantom function enable. Since the bridge does not support phantom functions, this bit is
read-only 0b.
8
ETFE
R
Extended tag field enable. Since the bridge does not support extended tags, this bit is
read-only 0b.
7:5
MPS
RW
Maximum payload size. This field is programmed by host software to set the maximum size of
posted writes or read completions that the bridge can initiate. This field is encoded as:
000
001
010
011
100
101
110
111
4
ERO
3
URRE
R
RW
= 128B (default)
= 256B
= 512B
= 1024B
= 2048B
= 4096B
= Reserved
= Reserved
Enable relaxed ordering. Since the bridge does not support relaxed ordering, this bit is
read-only 0b.
Unsupported request reporting enable. If this bit is set, then the bridge sends an
ERR_NONFATAL message to the root complex when an unsupported request is received.
0 = Do not report unsupported requests to the root complex (default)
1 = Report unsupported requests to the root complex
2
FERE
RW
Fatal error reporting enable. If this bit is set, then the bridge is enabled to send ERR_FATAL
messages to the root complex when a system error event occurs.
0 = Do not report fatal errors to the root complex (default)
1 = Report fatal errors to the root complex
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Table 4-26. Device Control Register Description (continued)
BIT
1
FIELD NAME
ACCESS
NFERE
RW
DESCRIPTION
Nonfatal error reporting enable. If this bit is set, then the bridge is enabled to send
ERR_NONFATAL messages to the root complex when a system error event occurs.
0 = Do not report nonfatal errors to the root complex (default)
1 = Report nonfatal errors to the root complex
0
CERE
RW
Correctable error reporting enable. If this bit is set, then the bridge is enabled to send
ERR_COR messages to the root complex when a system error event occurs.
0 = Do not report correctable errors to the root complex (default)
1 = Report correctable errors to the root complex
4.51 Device Status Register
The device status register provides PCI Express device specific information to the system. See Table 4-27
for a complete description of the register contents.
PCI register offset:
7Ah
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
15
0
0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-27. Device Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
15:6
RSVD
R
Reserved. Returns 00 0000 0000b when read.
5
PEND
RU
Transaction pending. This bit is set when the bridge has issued a non-posted transaction that
has not been completed.
4
APD
RU
AUX power detected. This bit indicates that AUX power is present.
0 = No AUX power detected
1 = AUX power detected
3
URD
RCU
Unsupported request detected. This bit is set by the bridge when an unsupported request is
received.
2
FED
RCU
Fatal error detected. This bit is set by the bridge when a fatal error is detected.
1
NFED
RCU
Nonfatal error detected. This bit is set by the bridge when a nonfatal error is detected.
0
CED
RCU
Correctable error detected. This bit is set by the bridge when a correctable error is detected.
4.52 Link Capabilities Register
The link capabilities register indicates the link specific capabilities of the bridge. See Table 4-28 for a
complete description of the register contents.
PCI register offset:
7Ch
Register type:
Read-only
Default value:
72
000Y XC11h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
1
17
y
16
y
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
y
x
x
x
1
1
0
0
0
0
0
1
0
0
0
1
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Table 4-28. Link Capabilities Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
31:24
PORT_NUM
R
Port number. This field indicates port number for the PCI Express link. This field is read-only
00h indicating that the link is associated with port 0.
23:22
RSVD
R
Reserved. Return 00b when read.
21
LBN_CAP
R
Link bandwidth notification. This bit is hardwired to 0b since this field is not applicable to a
bridge.
20
DLLLAR_CAP
R
DLL link active reporting capable. This bit is hardwired to 0b since the bridge does not support
this capability.
19
SDER_CAP
R
Surprise down error reporting capable. This bit is hardwired to 0b since the bridge does not
support this capability.
18
CLK_PM
R
Clock Power Management. This bit is hardwired to 1 to indicate that XIO2001 supports Clock
Power Management through CLKREQ protocol.
L1_LATENCY
R
L1 exit latency. This field indicates the time that it takes to transition from the L1 state to the L0
state. Bit 6 (CCC) in the link control register (offset 80h, see Section 4.53) equals 1b for a
common clock and equals 0b for an asynchronous clock.
17:15
For a common reference clock, the value of this field is determined by bits 20:18
(L1_EXIT_LAT_ASYNC) of the control and diagnostic register 1 (offset C4h, see Section 4.62).
For an asynchronous reference clock, the value of this field is determined by bits 17:15
(L1_EXIT_LAT_COMMON) of the control and diagnostic register 1 (offset C4h, see
Section 4.62).
14:12
L0S_LATENCY
R
L0s exit latency. This field indicates the time that it takes to transition from the L0s state to the
L0 state. Bit 6 (CCC) in the link control register (offset 80h, see Section 4.53) equals 1b for a
common clock and equals 0b for an asynchronous clock.
For a common reference clock, the value of 011b indicates that the L1 exit latency falls between
256 ns to less than 512 ns.
For an asynchronous reference clock, the value of 100b indicates that the L1 exit latency falls
between 512 ns to less than 1 µs.
11:10
ASLPMS
R
Active state link PM support. This field indicates the level of active state power management
that the bridge supports. The value 11b indicates support for both L0s and L1 through active
state power management.
9:4
MLW
R
Maximum link width. This field is encoded 00 0001b to indicate that the bridge only supports a
x1 PCI Express link.
3:0
MLS
R
Maximum link speed. This field is encoded 1h to indicate that the bridge supports a maximum
link speed of 2.5 Gb/s.
4.53 Link Control Register
The link control register controls link specific behavior. See Table 4-29 for a complete description of the
register contents.
PCI register offset:
80h
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0Y0Xh
14
0
13
0
12
0
11
0
10
0
9
0
8
y
7
0
6
0
5
0
4
0
3
0
2
0
1
x
0
x
Table 4-29. Link Control Register Description
BIT
15:12
FIELD NAME
ACCESS
DESCRIPTION
RSVD
R
Reserved. Returns 0h when read.
11
LABW_IEN
R
Link autonomous bandwidth interrupt enable. This bit is hardwired to 0b since this field is
not applicable to a bridge.
10
LBWN_IEN
R
Link bandwidth management interrupt enable. This bit is hardwired to 0b since this field is
not applicable to a bridge.
9
HWAW_DIS
R
Hardware autonomous width disable. This bit is hardwired to 0b since this field is not
supported by this bridge.
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Table 4-29. Link Control Register Description (continued)
BIT
8
FIELD NAME
ACCESS
CPM_EN
RW
DESCRIPTION
Clock Power Management Enable. This bit is used to enable the bridge to use CLKREQ
for clock power management
0 = Clock Power Management is disabled. CLKREQ is held low.
1 = Clock Power Management is enabled and the bridge is permitted to use the
CLKREQ signal to allow the REFCLK input to be stopped
The default value for this is bit is determined by bit 23 (CPM_EN_DEF_OVRD) in
the general control register (offset D4h, see Section 4.65).
7
ES
RW
Extended synch. This bit forces the bridge to extend the transmission of FTS ordered sets
and an extra TS2 when exiting from L1 prior to entering to L0.
0 = Normal synch (default)
1 = Extended synch
6
CCC
RW
Common clock configuration. When this bit is set, it indicates that the bridge and the
device at the opposite end of the link are operating with a common clock source. A value
of 0b indicates that the bridge and the device at the opposite end of the link are operating
with separate reference clock sources. The bridge uses this common clock configuration
information to report the L0s and L1 exit latencies.
0 = Reference clock is asynchronous (default)
1 = Reference clock is common
5
RL
R
Retrain link. This bit has no function and is read-only 0b.
4
LD
R
Link disable. This bit has no function and is read-only 0b.
3
RCB
RW
Read completion boundary. This bit is an indication of the RCB of the root complex. The
state of this bit has no affect on the bridge, since the RCB of the bridge is fixed at 128
bytes.
0 = 64 bytes (default)
1 = 128 bytes
2
1:0
RSVD
R
ASLPMC
Reserved. Returns 0b when read.
RW
Active state link PM control. This field enables and disables the active state PM. The
default value for this is bit is determined by bits 29:28 (ASPM_CTRL_DEF_OVRD) in the
general control register (offset D4h, see Section 4.65).
00
01
10
11
=
=
=
=
Active state PM disabled (default)
L0s entry enabled
L1 entry enabled
L0s and L1 entry enabled
4.54 Link Status Register
The link status register indicates the current state of the PCI Express link. See Table 4-30 for a complete
description of the register contents.
PCI register offset:
82h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
15
0
X011h
14
0
13
0
12
x
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
1
3
0
2
0
1
0
0
1
Table 4-30. Link Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
15
LABW
R
Link autonomous bandwidth status. This bit has no function and is read-only 0b.
14
LBWM
R
Link bandwidth management status. This bit has no function and is read-only 0b.
13
DLLLA
R
Data link layer link active. This bit has no function and is read-only 0b.
12
SCC
R
Slot clock configuration. This bit indicates that the bridge uses the same physical reference
clock that the platform provides on the connector. If the bridge uses an independent clock
irrespective of the presence of a reference on the connector, then this bit must be cleared.
0 = Independent 125-MHz reference clock is used
1 = Common 100-MHz reference clock is used
74
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Table 4-30. Link Status Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
11
LT
R
Link training. This bit has no function and is read-only 0b.
10
TE
R
Retrain link. This bit has no function and is read-only 0b.
9:4
NLW
R
Negotiated link width. This field is read-only 00 0001b indicating the lane width is x1.
3:0
LS
R
Link speed. This field is read-only 1h indicating the link speed is 2.5 Gb/s.
4.55 Serial-Bus Data Register
The serial-bus data register reads and writes data on the serial-bus interface. Write data is loaded into this
register prior to writing the serial-bus slave address register (offset B2h, see Section 4.57) that initiates the
bus cycle. When reading data from the serial bus, this register contains the data read after bit 5
(REQBUSY) of the serial-bus control and status register (offset B3h, see Section 4.58) is cleared. This
register is reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
PCI register offset:
B0h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
7
0
00h
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.56 Serial-Bus Word Address Register
The value written to the serial-bus word address register represents the word address of the byte being
read from or written to the serial-bus device. The word address is loaded into this register prior to writing
the serial-bus slave address register (offset B2h, see Section 4.57) that initiates the bus cycle. This
register is reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
PCI register offset:
B1h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
4.57 Serial-Bus Slave Address Register
The serial-bus slave address register indicates the slave address of the device being targeted by the
serial-bus cycle. This register also indicates if the cycle is a read or a write cycle. Writing to this register
initiates the cycle on the serial interface. See Table 4-31 for a complete description of the register
contents.
PCI register offset:
B2h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
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0
5
0
4
0
3
0
2
0
1
0
0
0
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Table 4-31. Serial-Bus Slave Address Register Descriptions
BIT
7:1 (1)
0 (1)
ACCESS
DESCRIPTION
SLAVE_ADDR
FIELD NAME
RW
Serial-bus slave address. This 7-bit field is the slave address for a serial-bus read or write
transaction. The default value for this field is 000 0000b.
RW_CMD
RW
Read/write command. This bit determines if the serial-bus cycle is a read or a write cycle.
0 = A single byte write is requested (default).
1 = A single byte read is requested.
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.58 Serial-Bus Control and Status Register
The serial-bus control and status register controls the behavior of the serial-bus interface. This register
also provides status information about the state of the serial bus. See Table 4-32 for a complete
description of the register contents.
PCI register offset:
B3h
Register type:
Read-only, Read/Write, Read/Clear
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-32. Serial-Bus Control and Status Register Description
BIT
7 (1)
FIELD NAME
PROT_SEL
ACCESS
RW
DESCRIPTION
Protocol select. This bit selects the serial-bus address mode used.
0 = Slave address and word address are sent on the serial-bus (default)
1 = Only the slave address is sent on the serial-bus
6
5 (1)
RSVD
REQBUSY
R
RU
Reserved. Returns 0b when read.
Requested serial-bus access busy. This bit is set when a software-initiated serial-bus cycle
is in progress.
0 = No serial-bus cycle
1 = Serial-bus cycle in progress
4 (1)
ROMBUSY
RU
Serial EEPROM access busy. This bit is set when the serial EEPROM circuitry in the bridge
is downloading register defaults from a serial EEPROM.
0 = No EEPROM activity
1 = EEPROM download in progress
3 (1)
SBDETECT
RWU
Serial EEPROM access busy. This bit is set when the serial EEPROM circuitry in the bridge
is downloading register defaults from a serial EEPROM.
Note: A serial EEPROM is only detected once following PERST.
0 = No EEPROM present, EEPROM load process does not happen. GPIO4//SCL and
GPIO3//SDA terminals are configured as GPIO signals.
1 = EEPROM present, EEPROM load process takes place. GPIO4//SCL and
GPIO3//SDA terminals are configured as serial-bus signals.
2 (1)
SBTEST
RW
Serial-bus test. This bit is used for internal test purposes. This bit controls the clock source
for the serial interface clock.
0 = Serial-bus clock at normal operating frequency ~ 60 kHz (default)
1 = Serial-bus clock frequency increased for test purposes ~ 4 MHz
1 (1)
SB_ERR
RCU
Serial-bus error. This bit is set when an error occurs during a software-initiated serial-bus
cycle.
0 = No error
1 = Serial-bus error
(1)
76
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-32. Serial-Bus Control and Status Register Description (continued)
BIT
0 (1)
FIELD NAME
ACCESS
DESCRIPTION
RCU
Serial EEPROM load error. This bit is set when an error occurs while downloading registers
from serial EEPROM.
ROM_ERR
0 = No error
1 = EEPROM load error
4.59 GPIO Control Register
This register controls the direction of the five GPIO terminals. This register has no effect on the behavior
of GPIO terminals that are enabled to perform secondary functions. The secondary functions share GPIO0
(CLKRUN), GPIO1 (PWR_OVRD), GPIO3 (SDA), and GPIO4 (SCL). See Table 4-33 for a complete
description of the register contents.
PCI register offset:
B4h
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-33. GPIO Control Register Description
BIT
15:5
4
(1)
FIELD NAME
ACCESS
RSVD
GPIO4_DIR
R
RW
DESCRIPTION
Reserved. Return 000h when read.
GPIO 4 data direction. This bit selects whether GPIO4 is in input or output mode.
0 = Input (default)
1 = Output
3 (1)
GPIO3_DIR
RW
GPIO 3 data direction. This bit selects whether GPIO3 is in input or output mode.
0 = Input (default)
1 = Output
2 (1)
GPIO2_DIR
RW
GPIO 2 data direction. This bit selects whether GPIO2 is in input or output mode.
0 = Input (default)
1 = Output
(1)
GPIO1_DIR
RW
GPIO 1 data direction. This bit selects whether GPIO1 is in input or output mode.
0 = Input (default)
1 = Output
0 (1)
GPIO0_DIR
RW
GPIO 0 data direction. This bit selects whether GPIO0 is in input or output mode.
0 = Input (default)
1 = Output
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.60 GPIO Data Register
This register reads the state of the input mode GPIO terminals and changes the state of the output mode
GPIO terminals. Writing to a bit that is in input mode or is enabled for a secondary function is ignored. The
secondary functions share GPIO0 (CLKRUN), GPIO1 (PWR_OVRD), GPIO3 (SDA), and GPIO4 (SCL).
The default value at power up depends on the state of the GPIO terminals as they default to
general-purpose inputs. See Table 4-34 for a complete description of the register contents.
PCI register offset:
B6h
Register type:
Read-only, Read/Write
Default value:
00XXh
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BIT NUMBER
RESET STATE
15
0
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14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
x
3
x
2
x
1
x
0
x
Table 4-34. GPIO Data Register Description
BIT
(1)
FIELD NAME
ACCESS
DESCRIPTION
15:5
RSVD
R
Reserved. Returns 000h when read.
4 (1)
GPIO4_DATA
RW
GPIO 4 data. This bit reads the state of GPIO4 when in input mode or changes the state of
GPIO4 when in output mode.
3 (1)
GPIO3_DATA
RW
GPIO 3 data. This bit reads the state of GPIO3 when in input mode or changes the state of
GPIO3 when in output mode.
2 (1)
GPIO2_DATA
RW
GPIO 2 data. This bit reads the state of GPIO2 when in input mode or changes the state of
GPIO2 when in output mode.
1 (1)
GPIO1_DATA
RW
GPIO 1 data. This bit reads the state of GPIO1 when in input mode or changes the state of
GPIO1 when in output mode.
0 (1)
GPIO0_DATA
RW
GPIO 0 data. This bit reads the state of GPIO0 when in input mode or changes the state of
GPIO0 when in output mode.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.61 TL Control and Diagnostic Register 0
The contents of this register are used for monitoring status and controlling behavior of the bridge. See
Table 4-35 for a complete description of the register contents. It is recommended that all values within this
register be left at the default value. Improperly programming fields in this register may cause
interoperability or other problems.
PCI register offset:
C0h
Register type:
Read/Write
Default value:
0000 0001h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
Table 4-35. Control and Diagnostic Register 0 Description
BIT
31:24
FIELD NAME
(1)
ACCES
S
DESCRIPTION
PRI_BUS_NUM
R
This field contains the captured primary bus number.
23:19 (1)
PRI_DEVICE_ NUM
R
This field contains the captured primary device number.
18
ALT_ERROR_REP
RW
Alternate Error Reporting. This bit controls the method that the XIO2001 uses for error
reporting.
0 = Advisory Non-Fatal Error reporting supported (default)
1 = Advisory Non-Fatal Error reporting not supported
17:16
15:14
(1)
RSVD
R
RSVD
RW
13:12
RSVD
R
11:7 (1)
RSVD
RW
(1)
78
R
Reserved. Returns 00b when read.
Reserved. Bits 15:14 default to 00b. If this register is programmed via EEPROM or another
mechanism, the value written into this field must be 00b.
Reserved. Returns 00b when read.
Reserved. Bits 11:7 default to 00000b. If this register is programmed via EEPROM or
another mechanism, the value written into this field must be 00000b.
6:3
RSVD
2 (1)
CFG_ACCESS
_MEM_REG
RW
Reserved. Returns 0h when read.
Configuration access to memory-mapped registers. When this bit is set, the bridge allows
configuration access to memory-mapped configuration registers.
1 (1)
RSVD
RW
Reserved. Bit 1 defaults to 0b. If this register is programmed via EEPROM or another
mechanism, the value written into this field must be 0b.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-35. Control and Diagnostic Register 0 Description (continued)
BIT
ACCES
S
FIELD NAME
0 (1)
FORCE_CLKREQ
RW
DESCRIPTION
Force CLKREQ. When this bit is set, the bridge will force the CLKREQ output to always be
asserted. The default setting for this bit is 1b.
4.62 Control and Diagnostic Register 1
The contents of this register are used for monitoring status and controlling behavior of the bridge. See
Table 4-36 for a complete description of the register contents. It is recommended that all values within this
register be left at the default value. Improperly programming fields in this register may cause
interoperability or other problems.
PCI register offset:
C4h
Register type:
Read/Write
Default value:
0012 0108h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
1
19
0
18
0
17
1
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
Table 4-36. Control and Diagnostic Register 1 Description
BIT
FIELD NAME
32:21
ACCESS
RSVD
R
DESCRIPTION
Reserved. Returns 000h when read.
20:18 (1)
L1_EXIT_LAT_A
SYNC
RW
L1 exit latency for asynchronous clock. When bit 6 (CCC) of the link control register (offset
80h, see Section 4.53) is set, the value in this field is mirrored in bits 17:15 (L1_LATENCY)
field in the link capabilities register (offset 7Ch, see Section 4.52). This field defaults to 100b.
17:15 (1)
L1_EXIT_LAT_C
OMMON
RW
L1 exit latency for common clock. When bit 6 (CCC) of the link control register (offset 80h, see
Section 4.53) is clear, the value in this field is mirrored in bits 17:15 (L1_LATENCY) field in the
link capabilities register (offset 7Ch, see Section 4.52). This field defaults to 100b.
14:11 (1)
RSVD
RW
Reserved. Bits 14:11 default to 0000b. If this register is programmed via EEPROM or another
mechanism, the value written into this field must be 0000b.
10 (1)
SBUS_RESET_M
ASK
RW
Secondary bus reset bit mask. When this bit is set, the bridge masks the reset caused by bit 6
(SRST) of the bridge control register (offset 3Eh, see Section 4.29). This bit defaults to 0b.
9:6 (1)
L1ASPM_TIMER
RW
L1ASPM entry timer. This field specifies the value (in 512-ns ticks) of the L1ASPM entry timer.
This field defaults to 0100b.
5:2 (1)
L0s_TIMER
RW
L0s entry timer. This field specifies the value (in 62.5-MHz clock ticks) of the L0s entry timer.
This field defaults to 0010b.
1:0 (1)
RSVD
RW
Reserved. Bits 1:0 default to 00b. If this register is programmed via EEPROM or another
mechanism, then the value written into this field must be 00b.
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.63 Control and Diagnostic Register 2
The contents of this register are used for monitoring status and controlling behavior of the bridge. See
Table 4-37 for a complete description of the register contents. It is recommended that all values within this
register be left at the default value. Improperly programming fields in this register may cause
interoperability or other problems.
PCI register offset:
C8h
Register type:
Read/Write
Default value:
3214 2000h
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BIT NUMBER
RESET STATE
31
0
30
0
29
1
28
1
27
0
26
0
25
1
24
0
23
0
22
0
21
0
20
1
19
0
18
1
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-37. Control and Diagnostic Register 2 Description
BIT
31:24
FIELD NAME
(1)
ACCESS
N_FTS_
ASYNC_CLK
23:16 (1) N_FTS_
COMMON_
CLK
DESCRIPTION
RW
N_FTS for asynchronous clock. When bit 6 (CCC) of the link control register (offset A0h, see
Section 4.53) is clear, the value in this field is the number of FTS that are sent on a transition from
L0s to L0. This field shall default to 32h.
RW
N_FTS for common clock. When bit 6 (CCC) of the link control register (offset A0h, see Section 4.53)
is set, the value in this field is the number of FTS that are sent on a transition from L0s to L0. This
field defaults to 14h.
15:13
PHY_REV
R
12:8 (1)
LINK_NUM
RW
Link number
EN_L2_PWR_
SAVE
RW
Enable L2 Power Savings
7
(1)
6
0= Power savings not enabled when in L2
1= Power savings enabled when in L2.
RSVD
5 (1)
PHY revision number
R
BAR0_EN
Reserved. Returns 0b when read.
RW
BAR 0 Enable.
0 = BAR at offset 10h is disabled (default)
1 = BAR at offset 10h is enabled
4:0 (1)
(1)
RSVD
RW
Reserved. Bits 4:0 default to 00000b. If this register is programmed via EEPROM or another
mechanism, then the value written into this field must be 00000b.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.64 Subsystem Access Register
The contents of this read/write register are aliased to the subsystem vendor ID and subsystem ID registers
at PCI offsets 84h and 86h. See Table 4-38 for a complete description of the register contents.
PCI register offset:
D0h
Register type:
Read/Write
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 4-38. Subsystem Access Register Description
ACCESS
DESCRIPTION
31:16 (1)
BIT
SubsystemID
RW
Subsystem ID. The value written to this field is aliased to the subsystem ID register at PCI
offset 46h (see Section 4.33).
15:0 (1)
SubsystemVendorID
RW
Subsystem vendor ID. The value written to this field is aliased to the subsystem vendor ID
register at PCI offset 44h (see Section 4.32).
(1)
80
FIELD NAME
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.65 General Control Register
This read/write register controls various functions of the bridge. See Table 4-39 for a complete description
of the register contents.
PCI register offset:
D4h
Register type:
Read-only, Read/Write
Default value:
8600 025Fh
BIT NUMBER
RESET STATE
31
1
30
0
29
0
28
0
27
0
26
1
25
1
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
1
0
0
1
0
1
1
1
1
1
Table 4-39. General Control Register Description
BIT
31:30
(1)
FIELD NAME
ACCESS
CFG_RETRY_CN
TR
RW
DESCRIPTION
Configuration retry counter. Configures the amount of time that a configuration request must be
retried on the secondary PCI bus before it may be completed with configuration retry status on
the PCI Express side.
00 =
01 =
10 =
11 =
29:28 (1)
ASPM_CTRL_DE
F_OVRD
RW
25 µs
1 ms
25 ms (default)
50 ms
Active State Power Management Control Default Override. These bits are used to determine the
power up default for bits 1:0 of the Link Control Register in the PCI Express Capability Structure.
00 =
01 =
10 =
11 =
Power on default
(default)
Power on default
(01b)
Power on default
(10b)
Power on default
and L1s (11b)
indicates that the active state power management is disable (00b)
indicates that the active state power management is enabled for L0s
indicates that the active state power management is enabled for L1s
indicates that the active state power management is enabled for L0s
27 (1)
LOW_POWER_E
N
RW
Low-power enable. When this bit is set, the half-amplitude, no pre-emphasis mode for the PCI
Express TX drivers is enabled. The default for this bit is 0b.
26 (1)
PCI_PM_VERSIO
N_CTRL
RW
PCI power management version control. This bit controls the value reported in bits 2:0
(PM_VERSION) in the power management capabilities register (offset 4Ah, see Section 4.36). It
also controls the value of bit 3 (NO_SOFT_RESET) in the power management control/status
register (offset 4Ch, see Section 4.37).
0 = Version fields reports 010b and NO_SOFT_RESET reports 0b for Power
Management 1.1 compliance
1 = Version fields reports 011b and NO_SOFT_RESET reports 1b for Power
Management 1.2 compliance (default)
25 (1)
RSVD
RW
24
RSVD
R
23
(1)
CPM_EN_DEF_O
VRD
RW
Reserved. Bit 25 defaults to 0b. If this register is programmed via EEPROM or another
mechanism, then the value written into this field must be 0b.
Reserved. Returns 0b when read.
Clock power management enable default override. This bit determines the power-up default for
bits 1:0 (CPM_EN) of the link control register (offset 80h, see Section 4.53) in the PCI Express
Capability structure.
0 = Power-on default indicates that clock power management is disabled (00b) (default)
1 = Power-on default indicates that clock power management is enabled for L0s and L1
(11b)
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-39. General Control Register Description (continued)
BIT
FIELD NAME
22:20 (1)
POWER_OVRD
ACCESS
RW
DESCRIPTION
Power override. This bit field determines how the bridge responds when the slot power limit is
less than the amount of power required by the bridge and the devices behind the bridge.
000 = Ignore slot power limit (default).
001 = Assert the PWR_OVRD terminal.
010 = Disable secondary clocks selected by the clock mask register.
011 = Disable secondary clocks selected by the clock mask register and assert the
PWR_OVRD terminal.
100 = Respond with unsupported request to all transactions except for configuration
transactions (type 0 or type 1) and set slot power limit messages.
101,110, Reserved
111 =
19 (1)
READ_PREFETC
H_DIS
RW
Read Prefetch Disable. This bit is used to control the pre-fetch functionality on PCI memory read
transactions.
0 = Memory read, memory read line, and memory read multiple will be treated as
prefetchable reads (default)
1 = Memory read line, and memory read multiple will be treated as pre-fetchable reads.
Memory read will not be prefetchable. No auto-prefetch reads will be made for these
requests.
18:16 (1)
L0s_LATENCY
RW
L0s maximum exit latency. This field programs the maximum acceptable latency when exiting the
L0s state. This sets bits 8:6 (EP_L0S_LAT) in the device capabilities register (offset 74h, see
Section 4.49).
000 =
001 =
010 =
011 =
100 =
101 =
110 =
111 =
15:13 (1)
L1_LATENCY
RW
L1 maximum exit latency. This field programs the maximum acceptable latency when exiting the
L1 state. This sets bits 11:9 (EP_L1_LAT) in the device capabilities register (offset 74h, see
Section 4.49).
000 =
001 =
010 =
011 =
100 =
101 =
110 =
111 =
12 (1)
VC_CAP_EN
11 (2)
BPCC_E
Less than 64 ns (default)
64 ns up to less than 128 ns
128 ns up to less than 256 ns
256 ns up to less than 512 ns
512 ns up to less than 1 µs
1 µs up to less than 2 µs
2 µs to 4 µs
More than 4 µs
Less than 1 µs (default)
1 µs up to less than 2 µs
2 µs up to less than 4 µs
4 µs up to less than 8 µs
8 µs up to less than 16 µs
6 µs up to less than 32 µs
32 µs to 64 µs
More than 64 µs
R
VC Capability Structure Enable. This bit is hardwired to 0b indicating that the VC Capability
structure is permanently disabled.
RW
Bus power clock control enable. This bit controls whether the secondary bus PCI clocks are
stopped when the XIO2001 is placed in the D3 state. It is assumed that if the secondary bus
clocks are required to be active, that a reference clock continues to be provided on the PCI
Express interface.
0 = Secondary bus clocks are not stopped in D3 (default)
1 = Secondary bus clocks are stopped on D3
10 (2)
BEACON_ENABL
E
RW
Beacon enable. This bit controls the mechanism for waking up the physical PCI Express link
when in L2.
0 = WAKE mechanism is used exclusively. Beacon is not used (default)
1 = Beacon and WAKE mechanisms are used
(2)
82
These bits are sticky and must retain their value when the bridge is powered by VAUX.
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Table 4-39. General Control Register Description (continued)
BIT
9:8 (1)
FIELD NAME
ACCESS
MIN_POWER_S
CALE
RW
DESCRIPTION
Minimum power scale. This value is programmed to indicate the scale of bits 7:0
(MIN_POWER_VALUE).
00 =
01 =
10 =
11 =
7:0 (1)
MIN_POWER_VA
LUE
RW
1.0x
0.1x
0.01x (default)
0.001x
Minimum power value. This value is programmed to indicate the minimum power requirements.
This value is multiplied by the minimum power scale field (bits 9:8) to determine the minimum
power requirements for the bridge. The default is 5Fh, indicating that the bridge requires 0.95 W
of power. This field can be reprogrammed through an EEPROM or the system BIOS.
4.66 Clock Control Register
This register enables and disables the PCI clock outputs (CLKOUT). See Table 4-40 for a complete
description of the register contents.
PCI register offset:
D8h
Register type:
Read-only, Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-40. Clock Control Register Description
BIT
7
(1)
FIELD NAME
RSVD
ACCESS
R
6 (1)
DESCRIPTION
Reserved. Returns 0b when read.
Clock output 6 disable. This bit disables secondary CLKOUT6.
CLOCK6_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
5 (1)
Clock output 5 disable. This bit disables secondary CLKOUT5.
CLOCK5_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
4
(1)
Clock output 4 disable. This bit disables secondary CLKOUT4.
CLOCK4_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
3 (1)
Clock output 3 disable. This bit disables secondary CLKOUT3.
CLOCK3_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
2 (1)
Clock output 2 disable. This bit disables secondary CLKOUT2.
CLOCK2_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
1 (1)
Clock output 1 disable. This bit disables secondary CLKOUT1.
CLOCK1_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
0 (1)
Clock output 0 disable. This bit disables secondary CLKOUT0.
CLOCK0_DISABLE
RW
0 = Clock enabled (default)
1 = Clock disabled
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.67
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Clock Mask Register
This register selects which PCI bus clocks are disabled when bits 22:20 (POWER_OVRD) in the general
control register (offset D4h, see Section 4.65) are set to 010h or 011h. This register has no effect on the
clock outputs if the POWER_OVRD bits are not set to 010h or 011h or if the slot power limit is greater
than the power required. See Table 4-41 for a complete description of the register contents.
PCI register offset:
D9h
Register type:
Read-only, Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-41. Clock Mask Register Description
BIT
7
6
FIELD NAME
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 0b when read.
Clock output 6 mask. This bit disables CLKOUT6 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
(1)
CLOCK6_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
5 (1)
Clock output 5 mask. This bit disables CLKOUT5 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK5_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
4 (1)
Clock output 4 mask. This bit disables CLKOUT4 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK4_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
3 (1)
Clock output 3 mask. This bit disables CLKOUT3 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK3_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
2 (1)
Clock output 2 mask. This bit disables CLKOUT2 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK2_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
1 (1)
Clock output 1 mask. This bit disables CLKOUT1 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK1_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
0 (1)
Clock output 0 mask. This bit disables CLKOUT0 when the POWER_OVRD bits are set to
010b or 011b and the slot power limit is exceeded.
CLOCK0_MASK
RW
0 = Clock enabled (default)
1 = Clock disabled
(1)
84
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Clock Run Status Register
The clock run status register indicates the state of the PCI clock-run features in the bridge. See
Table 4-42 for a complete description of the register contents.
PCI register offset:
DAh
Register type:
Read-only
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-42. Clock Run Status Register Description
BIT
7:1
0
FIELD NAME
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 000 0000b when read.
(1)
Secondary clock status. This bit indicates the status of the PCI bus secondary clock
outputs.
SEC_CLK_STATUS
RU
0 = Secondary clock running
1 = Secondary clock stopped
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.69 Arbiter Control Register
The arbiter control register controls the bridge internal arbiter. The arbitration scheme used is a two-tier
rotational arbitration. The bridge is the only secondary bus master that defaults to the higher priority
arbitration tier. See Table 4-43 for a complete description of the register contents.
PCI register offset:
DCh
Register type:
Read/Write
Default value:
40h
BIT NUMBER
RESET STATE
7
0
6
1
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-43. Clock Control Register Description
BIT
7
FIELD NAME
ACCESS
DESCRIPTION
RW
Bus parking mode. This bit determines where the internal arbiter parks the secondary bus.
When this bit is set, the arbiter parks the secondary bus on the bridge. When this bit is
cleared, the arbiter parks the bus on the last device mastering the secondary bus.
(1)
PARK
0 = Park the secondary bus on the last secondary bus master (default)
1 = Park the secondary bus on the bridge
6 (1)
Bridge tier select. This bit determines in which tier the bridge is placed in the arbitration
scheme.
BRIDGE_TIER_SEL
RW
0 = Lowest priority tier
1 = Highest priority tier (default)
5 (1)
GNT5 tier select. This bit determines in which tier GNT5 is placed in the arbitration
scheme.
TIER_SEL5
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
4 (1)
GNT4 tier select. This bit determines in which tier GNT4 is placed in the arbitration
scheme.
TIER_SEL4
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
3 (1)
GNT3 tier select. This bit determines in which tier GNT3 is placed in the arbitration
scheme.
TIER_SEL3
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
2 (1)
GNT2 tier select. This bit determines in which tier GNT2 is placed in the arbitration
scheme.
TIER_SEL2
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
1
(1)
GNT1 tier select. This bit determines in which tier GNT1 is placed in the arbitration
scheme.
TIER_SEL1
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
0 (1)
GNT0 tier select. This bit determines in which tier GNT0 is placed in the arbitration
scheme.
TIER_SEL0
RW
0 = Lowest priority tier (default)
1 = Highest priority tier
(1)
86
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.70 Arbiter Request Mask Register
The arbiter request mask register enables and disables support for requests from specific masters on the
secondary bus. The arbiter request mask register also controls if a request input is automatically masked
on an arbiter time-out. See Table 4-44 for a complete description of the register contents.
PCI register offset:
DDh
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-44. Arbiter Request Mask Register Description
BIT
7
(1)
FIELD NAME
ARB_TIMEOUT
ACCESS
DESCRIPTION
RW
Arbiter time-out. This bit enables the arbiter time-out feature. The arbiter time-out is
defined as the number of PCI clocks after the PCI bus has gone idle for a device to assert
FRAME before the arbiter assumes the device will not respond.
0 = Arbiter time disabled (default)
1 = Arbiter time-out set to 16 PCI clocks
6 (1)
AUTO_MASK
RW
Automatic request mask. This bit enables automatic request masking when an arbiter
time-out occurs.
0 = Automatic request masking disabled (default)
1 = Automatic request masking enabled
5 (1)
REQ5_MASK
RW
Request 5 (REQ5) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 5 (default)
1 = Ignore request 5
4
(1)
REQ4_MASK
RW
Request 4 (REQ4) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 4 (default)
1 = Ignore request 4
3 (1)
REQ3_MASK
RW
Request 3 (REQ3) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 3 (default)
1 = Ignore request 3
2
(1)
REQ2_MASK
RW
Request 2 (REQ2) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 2 (default)
1 = Ignore request 2
1 (1)
REQ1_MASK
RW
Request 1 (REQ1) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 2 (default)
1 = Ignore request 2
0 (1)
REQ0_MASK
RW
Request 0 (REQ0) Mask. Setting this bit forces the internal arbiter to ignore requests
signal on request input 0.
0 = Use request 0 (default)
1 = Ignore request 0
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.71 Arbiter Time-Out Status Register
The arbiter time-out status register contains the status of each request (request 5–0) time-out. The
time-out status bit for the respective request is set if the device did not assert FRAME after the arbiter
time-out value. See Table 4-45 for a complete description of the register contents.
PCI register offset:
DEh
Register type:
Read/Clear
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-45. Arbiter Time-Out Status Register Description
BIT
7:6
5
FIELD NAME
ACCESS
RSVD
R
REQ5_TO
DESCRIPTION
Reserved. Returns 00b when read.
RCU
Request 5 Time Out Status
0 = No time-out
1 = Time-out has occurred
4
REQ4_TO
RCU
Request 4 Time Out Status
0 = No time-out
1 = Time-out has occurred
3
REQ3_TO
RCU
Request 3 Time Out Status
0 = No time-out
1 = Time-out has occurred
2
REQ2_TO
RCU
Request 2 Time Out Status
0 = No time-out
1 = Time-out has occurred
1
REQ1_TO
RCU
Request 1Time Out Status
0 = No time-out
1 = Time-out has occurred
0
REQ0_TO
RCU
Request 0 Time Out Status
0 = No time-out
1 = Time-out has occurred
4.72 Serial IRQ Mode Control Register
This register controls the behavior of the serial IRQ controller. See Table 4-46 for a complete description
of the register contents.
PCI register offset:
E0h
Register type:
Read-only, Read/Write
Default value:
BIT NUMBER
RESET STATE
88
7
0
00h
6
0
Classic PCI Configuration Space
5
0
4
0
3
0
2
0
1
0
0
0
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Table 4-46. Serial IRQ Mode Control Register Description
BIT
7:4
FIELD NAME
ACCESS
RSVD
R
DESCRIPTION
Reserved. Returns 0h when read.
Start frame pulse width. Sets the width of the start frame for a SERIRQ stream.
00 = 4 clocks (default)
3:2 (1)
START_WIDTH
RW
01 = 6 clocks
10 = 8 clocks
11 = Reserved
Poll mode. This bit selects between continuous and quiet mode.
1 (1)
POLLMODE
RW
0 = Continuous mode (default)
1 = Quiet mode
0 (1)
RW Drive mode. This bit selects the behavior of the serial IRQ controller during the
recovery cycle.
DRIVEMODE
RW
0 = Drive high (default)
1 = 3-state
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.73 Serial IRQ Edge Control Register
This register controls the edge mode or level mode for each IRQ in the serial IRQ stream. See Table 4-47
for a complete description of the register contents.
PCI register offset:
E2h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
15
0
0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-47. Serial IRQ Edge Control Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 15 edge mode
15 (1)
IRQ15_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 14 edge mode
14 (1)
IRQ14_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 13 edge mode
13 (1)
IRQ13_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 12 edge mode
12 (1)
IRQ12_MODE
RW
0 = Edge mode (default)
1 = Level mode
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-47. Serial IRQ Edge Control Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 11 edge mode
11 (1)
IRQ11_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 10 edge mode
10 (1)
IRQ10_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 9 edge mode
9 (1)
IRQ9_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 8 edge mode
8 (1)
IRQ8_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 7 edge mode
7 (1)
IRQ7_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 6 edge mode
6 (1)
IRQ6_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 5 edge mode
5 (1)
IRQ5_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 4 edge mode
4 (1)
IRQ4_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 3 edge mode
3 (1)
IRQ3_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 2 edge mode
2 (1)
IRQ2_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 1 edge mode
1 (1)
IRQ1_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 0 edge mode
0 (1)
IRQ0_MODE
RW
0 = Edge mode (default)
1 = Level mode
90
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4.74 Serial IRQ Status Register
This register indicates when a level mode IRQ is signaled on the serial IRQ stream. After a level mode
IRQ is signaled, a write-back of 1b to the asserted IRQ status bit re-arms the interrupt. IRQ interrupts that
are defined as edge mode in the serial IRQ edge control register are not reported in this status register.
See Table 4-48 for a complete description of the register contents.
PCI register offset:
E4h
Register type:
Read/Clear
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-48. Serial IRQ Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 15 asserted. This bit indicates that the IRQ15 has been asserted.
15 (1)
IRQ15
RCU
0 = Deasserted
1 = Asserted
IRQ 14 asserted. This bit indicates that the IRQ14 has been asserted.
14 (1)
IRQ14
RCU
0 = Deasserted
1 = Asserted
IRQ 13 asserted. This bit indicates that the IRQ13 has been asserted.
13 (1)
IRQ13
RCU
0 = Deasserted
1 = Asserted
IRQ 12 asserted. This bit indicates that the IRQ12 has been asserted.
12 (1)
IRQ12
RCU
0 = Deasserted
1 = Asserted
IRQ 11 asserted. This bit indicates that the IRQ11 has been asserted.
11 (1)
IRQ11
RCU
0 = Deasserted
1 = Asserted
IRQ 10 asserted. This bit indicates that the IRQ10 has been asserted.
10 (1)
IRQ10
RCU
0 = Deasserted
1 = Asserted
IRQ 9 asserted. This bit indicates that the IRQ9 has been asserted.
9 (1)
IRQ9
RCU
0 = Deasserted
1 = Asserted
IRQ 8 asserted. This bit indicates that the IRQ8 has been asserted.
8 (1)
IRQ8
RCU
0 = Deasserted
1 = Asserted
IRQ 7 asserted. This bit indicates that the IRQ7 has been asserted.
7 (1)
IRQ7
RCU
0 = Deasserted
1 = Asserted
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-48. Serial IRQ Status Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 6 asserted. This bit indicates that the IRQ6 has been asserted.
6 (1)
IRQ6
RCU
0 = Deasserted
1 = Asserted
IRQ 5 asserted. This bit indicates that the IRQ5 has been asserted.
5 (1)
IRQ5
RCU
0 = Deasserted
1 = Asserted
IRQ 4 asserted. This bit indicates that the IRQ4 has been asserted.
4 (1)
IRQ4
RCU
0 = Deasserted
1 = Asserted
IRQ 3 asserted. This bit indicates that the IRQ3 has been asserted.
3 (1)
IRQ3
RCU
0 = Deasserted
1 = Asserted
IRQ 2 asserted. This bit indicates that the IRQ2 has been asserted.
2 (1)
IRQ2
RCU
0 = Deasserted
1 = Asserted
IRQ 1 asserted. This bit indicates that the IRQ1 has been asserted.
1 (1)
IRQ1
RCU
0 = Deasserted
1 = Asserted
IRQ 0 asserted. This bit indicates that the IRQ0 has been asserted.
0 (1)
IRQ0
RCU
0 = Deasserted
1 = Asserted
4.75 Pre-Fetch Agent Request Limits Register
This register is used to set the Pre-Fetch Agent's limits on retrieving data using upstream reads. See
Table 4-49 for a complete description of the register contents.
PCI register offset:
E8h
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
0443h
14
0
13
0
12
0
11
0
10
1
9
0
8
0
7
0
6
1
5
0
4
0
3
0
2
0
1
1
0
1
Table 4-49. Pre-Fetch Agent Request Limits Register Description
BIT
FIELD NAME
15:12
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 0h when read.
Request count limit. Determines the number of Pre-Fetch reads that takes place in each
burst.
11:8 (1)
PFA_REQ_
CNT_LIMIT
RW
4'h0 = Auto-prefetch agent is disabled.
4'h1 = Thread is limited to one buffer. No auto-prefetch reads will be generated.
4'h2:F = Thread will be limited to initial read and (PFA_REQ_CNT_LIMIT – 1)
(1)
92
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 4-49. Pre-Fetch Agent Request Limits Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
Completion cache mode. Determines the rules for completing the caching process.
00 = No caching.
• Pre-fetching is disabled.
• All remaining read completion data will be discarded after any of the data has been
returned to the PCI master.
7:6
PFA_CPL_CACHE_
MODE
RW
01 = Light caching.
• Pre-fetching is enabled.
• All remaining read completion data will be discarded after data has been returned to
the PCI master and the PCI master terminated the transfer.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the bridge has terminated the transfer with RETRY.
10 = Full caching.
• Pre-fetching is enabled.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the PCI master terminated the transfer.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the bridge has terminated the transfer with RETRY.
11 = Reserved.
5:4
RSVD
R
Reserved. Returns 00b when read.
Request Length Limit. Determines the number of bytes in the thread that the pre-fetch
agent will read for that thread.
0000 = 64 bytes
0001 = 128 bytes
0010 = 256 bytes
3:0
PFA_REQ_LENGT
H_LIMIT
RW
0011 = 512 bytes
0100 = 1 Kbytes
0101 = 2 Kbytes
0110 = 4 Kbytes
0111 = 8 Kbytes
1000:1111 = Reserved
4.76 Cache Timer Transfer Limit Register
This register is used to set the number of PCI cycle starts that have to occur without a read hit on the
completion data buffer, before the cache data can be discarded. See Table 4-50 for a complete
description of the register contents.
PCI register offset:
EAh
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
0008h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
1
2
0
1
0
0
0
Table 4-50. Cache Timer Transfer Limit Register Description
BIT
(1)
FIELD NAME
15:8
RSVD
7:0 (1)
CACHE_TMR_XFR
_LIMIT
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 00h when read.
Number of PCI cycle starts that have to occur without a read hit on the completion data
buffer, before the cache data can be discarded.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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4.77 Cache Timer Lower Limit Register
Minimum number of clock cycles that must have passed without a read hit on the completion data buffer
before the "cache miss limit" check can be triggered. See Table 4-51 for a complete description of the
register contents.
PCI register offset:
ECh
Register type:
Read/Clear
Default value:
007Fh
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
1
5
1
4
1
3
1
2
1
1
1
0
1
Table 4-51. Cache Timer Lower Limit Register Description
BIT
FIELD NAME
15:12
11:0
(1)
ACCESS
RSVD
(1)
R
CACHE_TIMER
_LOWER_LIMIT
DESCRIPTION
Reserved. Returns 0h when read.
RW
Minimum number of clock cycles that must have passed without a read hit on the
completion data buffer before the "cache miss limit" check can be triggered.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
4.78 Cache Timer Upper Limit Register
Discard cached data after this number of clock cycles have passed without a read hit on the completion
data buffer. See Table 4-52 for a complete description of the register contents.
PCI register offset:
EEh
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
01C0h
14
0
13
0
12
0
11
0
10
0
9
0
8
1
7
1
6
1
5
0
4
0
3
0
2
0
1
0
0
0
Table 4-52. Cache Timer Upper Limit Register Description
BIT
FIELD NAME
15:12
RSVD
11:0 (1)
CACHE_TIMER
_UPPER_LIMIT
(1)
94
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 0h when read.
Discard cached data after this number of clock cycles have passed without a read hit on
the completion data buffer.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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PCI Express Extended Configuration Space
The programming model of the PCI Express extended configuration space is compliant to the PCI Express
Base Specification and the PCI Express to PCI/PCI-X Bridge Specification programming models. The PCI
Express extended configuration map uses the PCI Express advanced error reporting capability.
All bits marked with a I are sticky bits and are reset by a global reset (GRST) or the internally-generated
power-on reset. All bits marked with a I are reset by a PCI Express reset (PERST), a GRST, or the
internally-generated power-on reset. The remaining register bits are reset by a PCI Express hot reset,
PERST, GRST, or the internally-generated power-on reset.
Table 5-1. PCI Express Extended Configuration Register Map
REGISTER NAME
Next capability offset / capability version
OFFSET
PCI Express advanced error reporting capabilities ID
100h
Uncorrectable error status register (1)
Uncorrectable error mask register
10Ch
Correctable error status register (1)
110h
(1)
114h
Advanced error capabilities and control (1)
118h
Header log register (1)
11Ch
Header log register (1)
120h
(1)
124h
Header log register
Header log register (1)
128h
Secondary uncorrectable error status (1)
12Ch
Secondary uncorrectable error mask (1)
130h
Secondary uncorrectable error severity register (1)
134h
Secondary error capabilities and control register (1)
138h
(1)
13Ch
Secondary header log register (1)
140h
Secondary header log register (1)
144h
Secondary header log register (1)
148h
Reserved
14Ch–FFCh
Secondary header log register
5.1
108h
Uncorrectable error severity register (1)
Correctable error mask
(1)
104h
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Advanced Error Reporting Capability ID Register
This read-only register identifies the linked list item as the register for PCI Express advanced error
reporting capabilities. The register returns 0001h when read.
PCI Express extended register offset: 100h
Register type:
Read-only
Default value:
0001h
BIT NUMBER
RESET STATE
15
0
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14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
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0
1
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Next Capability Offset/Capability Version Register
This read-only register identifies the next location in the PCI Express extended capabilities link list. The
upper 12 bits in this register shall be 000h, indicating that the Advanced Error Reporting Capability is the
last capability in the linked list. The least significant four bits identify the revision of the current capability
block as 1h.
PCI Express extended register offset:
102h
Register type:
Read-only
Default value:
0001h
BIT NUMBER
RESET STATE
5.3
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
Uncorrectable Error Status Register
The uncorrectable error status register reports the status of individual errors as they occur on the primary
PCI Express interface. Software may only clear these bits by writing a 1b to the desired location. See
Table 5-2 for a complete description of the register contents.
PCI Express extended register offset:
104h
Register type:
Read-only, Read/Clear
Default value:
0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-2. Uncorrectable Error Status Register Description
BIT
31:22
21
20 (1)
19
(1)
DESCRIPTION
R
Reserved. Returns 000 0000 0000b when read.
R
ACS Violation. Not supported, ths bit returns 0b when read.
UR_ERROR
RCU
Unsupported request error. This bit is asserted when an unsupported request is received.
ECRC_ERROR
RCU
Extended CRC error. This bit is asserted when an extended CRC error is detected.
MAL_TLP
RCU
Malformed TLP. This bit is asserted when a malformed TLP is detected.
17 (1)
RX_OVERFLOW
RCU
Receiver overflow. This bit is asserted when the flow control logic detects that the
transmitting device has illegally exceeded the number of credits that were issued.
16 (1)
UNXP_CPL
RCU
Unexpected completion. This bit is asserted when a completion packet is received that
does not correspond to an issued request.
15 (1)
CPL_ABORT
RCU
Completer abort. This bit is asserted when the bridge signals a completer abort.
CPL_TIMEOUT
RCU
Completion time-out. This bit is asserted when no completion has been received for an
issued request before the time-out period.
13 (1)
FC_ERROR
RCU
Flow control error. This bit is asserted when a flow control protocol error is detected either
during initialization or during normal operation.
12 (1)
PSN_TLP
RCU
Poisoned TLP. This bit is asserted when a poisoned TLP is received.
11:6
RSVD
R
Reserved. Returns 00 0000b when read.
SD_ERROR
R
Surprise down error. Not supported, this bit returns 0b when read.
DLL_ERROR
RCU
(1)
5
4
(1)
3:0
96
ACS_VIOLATION
ACCESS
18 (1)
14
(1)
FIELD NAME
RSVD
RSVD
R
Data link protocol error. This bit is asserted if a data link layer protocol error is detected.
Reserved. Returns 0h when read.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Uncorrectable Error Mask Register
The uncorrectable error mask register controls the reporting of individual errors as they occur. When a
mask bit is set to 1b, the corresponding error status bit is not set, PCI Express error messages are
blocked, the header log is not loaded, and the first error pointer is not updated. See Table 5-3 for a
complete description of the register contents.
PCI Express extended register offset:
108h
Register type:
Read-only, Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-3. Uncorrectable Error Mask Register Description
BIT
31:22
21
20 (1)
FIELD NAME
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 000 0000 0000b when read.
ACS_VIOLATION_MASK
RW
ACS Violation mask. Not supported, this bit returns 0b when read.
UR_ERROR_MASK
RW
Unsupported request error mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
19 (1)
ECRC_ERROR_MASK
RW
Extended CRC error mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
18 (1)
MAL_TLP_MASK
RW
Malformed TLP mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
17 (1)
RX_OVERFLOW_MASK
RW
Receiver overflow mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
16 (1)
UNXP_CPL_MASK
RW
Unexpected completion mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
15 (1)
CPL_ABORT_MASK
RW
Completer abort mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
14 (1)
CPL_TIMEOUT_MASK
RW
Completion time-out mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
13 (1)
FC_ERROR_MASK
RW
Flow control error mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
12 (1)
PSN_TLP_MASK
RW
Poisoned TLP mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
11:6
RSVD
R
Reserved. Returns 000 0000b when read.
5
SD_ERROR_MASK
R
SD error mask. Not supported, returns 0b when read.
4 (1)
DLL_ERROR_MASK
RW
Data link protocol error mask
0 = Error condition is unmasked (default)
1 = Error condition is masked
3:0
(1)
RSVD
R
Reserved. Returns 0h when read.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Uncorrectable Error Severity Register
The uncorrectable error severity register controls the reporting of individual errors as ERR_FATAL or
ERR_NONFATAL. When a bit is set, the corresponding error condition is identified as fatal. When a bit is
cleared, the corresponding error condition is identified as nonfatal. See Table 5-4 for a complete
description of the register contents.
PCI Express extended register offset:
10Ch
Register type:
Read-only, Read/Write
Default value:
0006 2031h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
1
17
1
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
1
0
0
0
0
0
0
0
1
1
0
0
0
1
Table 5-4. Uncorrectable Error Severity Register Description
BIT
31:22
21
20 (1)
FIELD NAME
ACCESS
DESCRIPTION
RSVD
R
Reserved. Returns 000 0000 0000b when read.
ACS_VIOLATION_SEV
R
R
ACS violation severity. Not supported, returns 0b when read.
UR_ERROR_SEVRO
RW
Unsupported request error severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
19 (1)
ECRC_ERROR_SEVRR
RW
Extended CRC error severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
18 (1)
MAL_TLP_SEVR
RW
Malformed TLP severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
17 (1)
RX_OVERFLOW_SEVR
RW
Receiver overflow severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
16 (1)
UNXP_CPL_SEVRP
RW
Unexpected completion severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
15 (1)
CPL_ABORT_SEVR
RW
Completer abort severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
14 (1)
CPL_TIMEOUT_SEVR
RW
Completion time-out severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
13 (1)
FC_ERROR_SEVR
RW
Flow control error severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
12 (1)
PSN_TLP_SEVR
RW
Poisoned TLP severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
11:6
5
4
(1)
RSVD
R
Reserved. Returns 000 000b when read.
SD_ERROR_SEVR
R
SD error severity. Not supported, returns 1b when read.
DLL_ERROR_SEVR
RW
Data link protocol error severity
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL
(1)
98
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 5-4. Uncorrectable Error Severity Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
3:1
RSVD
R
Reserved. Retirms 000b wjem read/
0
RSVD
R
Reserved. Returns 1h when read.
5.6
Correctable Error Status Register
The correctable error status register reports the status of individual errors as they occur. Software may
only clear these bits by writing a 1b to the desired location. See Table 5-5 for a complete description of
the register contents.
PCI Express extended register offset:
110h
Register type:
Read-only, Read/Clear
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-5. Correctable Error Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
31:14
RSVD
R
13 (1)
ANFES
RCU
Advisory Non-Fatal Error Status. This bit is asserted when an Advisor Non-Fatal Error has
been reported.
REPLAY_TMOUT
RCU
Replay timer time-out. This bit is asserted when the replay timer expires for a pending request
or completion that has not been acknowledged.
12
(1)
11:9
(1)
RSVD
R
Reserved. Returns 000 0000 0000 0000 0000b when read.
Reserved. Returns 000b when read.
8 (1)
REPLAY_ROLL
RCU
REPLAY_NUM rollover. This bit is asserted when the replay counter rolls over after a pending
request or completion has not been acknowledged.
7 (1)
BAD_DLLP
RCU
Bad DLLP error. This bit is asserted when an 8b/10b error was detected by the PHY during
the reception of a DLLP.
6 (1)
BAD_TLP
RCU
Bad TLP error. This bit is asserted when an 8b/10b error was detected by the PHY during the
reception of a TLP.
5:1
RSVD
0 (1)
RX_ERROR
R
RCU
Reserved. Returns 00000b when read.
Receiver error. This bit is asserted when an 8b/10b error is detected by the PHY at any time.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Correctable Error Mask Register
The correctable error mask register controls the reporting of individual errors as they occur. When a mask
bit is set to 1b, the corresponding error status bit is not set, PCI Express error messages are blocked, the
header log is not loaded, and the first error pointer is not updated. See Table 5-6 for a complete
description of the register contents.
PCI Express extended register offset:
114h
Register type:
Read-only, Read/Write
Default value:
0000 2000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-6. Correctable Error Mask Register Description
BIT
FIELD NAME
31:14
RSVD
13 (1)
ANFEM
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 000 0000 0000 0000 0000b when read.
Advisory Non-Fatal Error Mask.
0 = Error condition is unmasked
1 = Error condition is masked (default)
12 (1)
REPLAY_TMOUT_MAS
K
11:9
RSVD
8 (1)
REPLAY_ROLL_MASK
RW
Replay timer time-out mask.
0 = Error condition is unmasked (default)
1 = Error condition is masked
R
RW
Reserved. Returns 000b when read.
REPLAY_NUM rollover mask.
0 = Error condition is unmasked (default)
1 = Error condition is masked
7 (1)
BAD_DLLP_MASK
RW
Bad DLLP error mask.
0 = Error condition is unmasked (default)
1 = Error condition is masked
6 (1)
BAD_TLP_MASK
RW
Bad TLP error mask.
0 = Error condition is unmasked (default)
1 = Error condition is masked
5:1
RSVD
0
RX_ERROR_MASK
(1)
R
RW
Reserved. Returns 00000b when read.
Receiver error mask.
0 = Error condition is unmasked (default)
1 = Error condition is masked
(1)
100
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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5.8
SCPS212B – MAY 2009 – REVISED JULY 2009
Advanced Error Capabilities and Control Register
The advanced error capabilities and control register allows the system to monitor and control the
advanced error reporting capabilities. See Table 5-7 for a complete description of the register contents.
PCI Express extended register
offset:
118h
Register type:
Read-only, Read/Write
Default value:
0000 00A0h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
Table 5-7. Advanced Error Capabilities and Control Register Description
BIT
FIELD NAME
31:9
RSVD
8 (1)
ECRC_CHK_EN
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 000 0000 0000 0000 0000 0000b when read.
Extended CRC check enable
0 = Extended CRC checking is disabled
1 = Extended CRC checking is enabled
7
ECRC_CHK_CAPABLE
6 (1)
R
ECRC_GEN_EN
RW
Extended CRC check capable. This read-only bit returns a value of 1b indicating that the
bridge is capable of checking extended CRC information.
Extended CRC generation enable
0 = Extended CRC generation is disabled
1 = Extended CRC generation is enabled
5
ECRC_GEN_CAPABLE
4:0 (1)
(1)
5.9
R
FIRST_ERR
RU
Extended CRC generation capable. This read-only bit returns a value of 1b indicating
that the bridge is capable of generating extended CRC information.
First error pointer. This 5-bit value reflects the bit position within the uncorrectable error
status register (offset 104h, see Section 5.3) corresponding to the class of the first error
condition that was detected.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Header Log Register
The header log register stores the TLP header for the packet that lead to the most recently detected error
condition. Offset 11Ch contains the first DWORD. Offset 128h contains the last DWORD (in the case of a
4DW TLP header). Each DWORD is stored with the least significant byte representing the earliest
transmitted. This register shall only be reset by a PCI Express reset (PERST), a GRST, or the
internally-generated power-on reset.
PCI Express extended register offset:
11Ch, 120h, 124h, and 128h
Register type:
Read-only
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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5.10 Secondary Uncorrectable Error Status Register
The secondary uncorrectable error status register reports the status of individual PCI bus errors as they
occur. Software may only clear these bits by writing a 1b to the desired location. See Table 5-8 for a
complete description of the register contents.
PCI Express extended register offset:
12Ch
Register type:
Read-only, Read/Clear
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-8. Secondary Uncorrectable Error Status Register Description
BIT
31:14
13
FIELD NAME
ACCESS
DESCRIPTION
RSVD
R
Reserved. Returns 000 0000 0000 0000 0000b when read.
INTERNAL_ERROR
R
Internal bridge error. This error bit is associated with a PCI-X error and returns 0b when
read.
12 (1)
SERR_DETECT
RCU
SERR assertion detected. This bit is asserted when the bridge detects the assertion of
SERR on the secondary bus.
11 (1)
PERR_DETECT
RCU
PERR assertion detected. This bit is asserted when the bridge detects the assertion of
PERR on the secondary bus.
10 (1)
DISCARD_TIMER
RCU
Delayed transaction discard timer expired. This bit is asserted when the discard timer
expires for a pending delayed transaction that was initiated on the secondary bus.
9 (1)
UNCOR_ADDR
RCU
Uncorrectable address error. This bit is asserted when the bridge detects a parity error
during the address phase of an upstream transaction.
8
7 (1)
(1)
102
UNCOR_ATTRIB
UNCOR_DATA
R
Uncorrectable attribute error. This error bit is associated with a PCI-X error and returns 0b
when read.
RCU
Uncorrectable data error. This bit is asserted when the bridge detects a parity error during
a data phase of an upstream write transaction, or when the bridge detects the assertion of
PERR when forwarding read completion data to a PCI device.
6
UNCOR_SPLTMSG
R
Uncorrectable split completion message data error. This error bit is associated with a
PCI-X error and returns 0b when read.
5
UNXPC_SPLTCMP
R
Unexpected split completion error. This error bit is associated with a PCI-X error and
returns 0b when read.
4
RSVD
R
Reserved. Returns 0b when read.
3 (1)
MASTER_ABORT
RCU
Received master abort. This bit is asserted when the bridge receives a master abort on
the PCI interface.
2 (1)
TARGET_ABORT
RCU
Received target abort. This bit is asserted when the bridge receives a target abort on the
PCI interface.
1
MABRT_SPLIT
R
Master abort on split completion. This error bit is associated with a PCI-X error and returns
0b when read.
0
TABRT_SPLIT
R
Target abort on split completion status. This error bit is associated with a PCI-X error and
returns 0b when read.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
PCI Express Extended Configuration Space
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5.11 Secondary Uncorrectable Error Mask Register
The secondary uncorrectable error mask register controls the reporting of individual errors as they occur.
When a mask bit is set to 1b, the corresponding error status bit is not set, PCI Express error messages
are blocked, the header log is not loaded, and the first error pointer is not updated. See Table 5-9 for a
complete description of the register contents.
PCI Express extended register offset:
130h
Register type:
Read-only, Read/Write
Default value:
0000 17A8h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
1
0
1
1
1
1
0
1
0
1
0
0
0
Table 5-9. Secondary Uncorrectable Error Mask Register Description
BIT
FIELD NAME
ACCESS
31:14
RSVD
13 (1)
INTERNAL_ERROR_MASK
RW
Internal bridge error. This mask bit is associated with a PCI-X error and has no effect
on the bridge.
12 (1)
SERR_DETECT_MASK
RW
SERR assertion detected
R
DESCRIPTION
Reserved. Returns 00 0000 0000 0000 0000b when read.
0 = Error condition is unmasked
1 = Error condition is masked (default)
11 (1)
PERR_DETECT_MASK
RW
PERR assertion detectedi
0 = Error condition is unmasked
1 = Error condition is masked (default)
10 (1)
DISCARD_TIMER_MASK
RW
Delayed transaction discard timer expired
0 = Error condition is unmasked
1 = Error condition is masked (default)
9 (1)
UNCOR_ADDR_MASK
RW
Uncorrectable address error
0 = Error condition is unmasked
1 = Error condition is masked (default)
8 (1)
UNCOR_ATTRIB_MASK
RW
Uncorrectable attribute error. This mask bit is associated with a PCI-X error and has
no effect on the bridge.
7 (1)
UNCOR_DATA_MASK
RW
Uncorrectable data error
0 = Error condition is unmasked
1 = Error condition is masked (default)
6 (1)
UNCOR_SPLTMSG_MASK
RW
Uncorrectable split completion message data error. This mask bit is associated with a
PCI-X error and has no effect on the bridge.
5 (1)
SC_ERROR_MASK
RW
Unexpected split completion error. This mask bit is associated with a PCI-X error and
has no effect on the bridge.
4
3
(1)
RSVD
MASTER_ABORT_MASK
R
RW
Reserved. Returns 0b when read.
Received master abort
0 = Error condition is unmasked
1 = Error condition is masked (default)
2 (1)
TARGET_ABORT_MASK
RW
Received target abort
0 = Error condition is unmasked
1 = Error condition is masked (default)
(1)
1 (1)
MABRT_SPLIT_MASK
RW
Master abort on split completion. This mask bit is associated with a PCI-X error and
has no effect on the bridge.
0
TABRT_SPLIT_MASK
R
Target abort on split completion. This mask bit is associated with a PCI-X error and
has no effect on the bridge.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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5.12 Secondary Uncorrectable Error Severity
The uncorrectable error severity register controls the reporting of individual errors as ERR_FATAL or
ERR_NONFATAL. When a bit is set, the corresponding error condition is identified as fatal. When a bit is
cleared, the corresponding error condition is identified as nonfatal. See Table 5-10 for a complete
description of the register contents.
PCI Express extended register offset: 134h
Register type:
Read-only, Read/Write
Default value:
0000 1340h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
1
0
0
1
1
0
1
0
0
0
0
0
0
Table 5-10. Secondary Uncorrectable Error Severity Register Description
BIT
FIELD NAME
ACCESS
31:14
RSVD
13 (1)
INTERNAL_ERROR_SEVR
RW
Internal bridge error. This severity bit is associated with a PCI-X error and has no effect
on the bridge.
12 (1)
SERR_DETECT_SEVR
RW
SERR assertion detected
R
DESCRIPTION
Reserved. Returns 00 0000 0000 0000 0000b when read.
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL (default)
11 (1)
PERR_DETECT_SEVR
RW
PERR assertion detected
0 = Error condition is signaled using ERR_NONFATAL (default)
1 = Error condition is signaled using ERR_FATAL
10 (1)
DISCARD_TIMER_SEVR
RW
Delayed transaction discard timer expired
0 = Error condition is signaled using ERR_NONFATAL (default)
1 = Error condition is signaled using ERR_FATAL
9 (1)
UNCOR_ADDR_SEVR
RW
Uncorrectable address error
0 = Error condition is signaled using ERR_NONFATAL
1 = Error condition is signaled using ERR_FATAL (default)
8 (1)
UNCOR_ATTRIB_SEVR
RW
Uncorrectable attribute error. This severity bit is associated with a PCI-X error and has
no effect on the bridge.
7 (1)
UNCOR_DATA_SEVR
RW
Uncorrectable data error
0 = Error condition is signaled using ERR_NONFATAL (default)
1 = Error condition is signaled using ERR_FATAL
6 (1)
UNCOR_SPLTMSG_SEVR
RW
Uncorrectable split completion message data error. This severity bit is associated with
a PCI-X error and has no effect on the bridge.
5 (1)
UNCOR_SPLTCMP_SEVR
RW
Unexpected split completion error. This severity bit is associated with a PCI-X error and
has no effect on the bridge.
4
3
(1)
RSVD
MASTER_ABORT_SEVR
R
RW
Reserved. Returns 0b when read.
Received master abort
0 = Error condition is signaled using ERR_NONFATAL (default)
1 = Error condition is signaled using ERR_FATAL
2 (1)
TARGET_ABORT_SEVR
RW
Received target aborta
0 = Error condition is signaled using ERR_NONFATAL (default)
1 = Error condition is signaled using ERR_FATAL
1 (1)
MABRT_SPLIT_SEVR
RW
Master abort on split completion. This severity bit is associated with a PCI-X error and
has no effect on the bridge.
0
TABRT_SPLIT_SEVR
R
Target abort on split completion. This severity bit is associated with a PCI-X error and
has no effect on the bridge.
(1)
104
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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5.13 Secondary Error Capabilities and Control Register
The secondary error capabilities and control register allows the system to monitor and control the
secondary advanced error reporting capabilities. See Table 5-11 for a complete description of the register
contents.
PCI Express extended register offset: 138h
Register type:
Read-only
Default value:
0000 0000h
BIT NUMBER
RESET STATE
31
0
30
0
29
0
28
0
27
0
26
0
25
0
24
0
23
0
22
0
21
0
20
0
19
0
18
0
17
0
16
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-11. Secondary Error Capabilities and Control Register Description
BIT
(1)
FIELD NAME
31:5
RSVD
4:0 (1)
SEC_FIRST_ERR
ACCESS
R
RU
DESCRIPTION
Reserved. Return 000 0000 0000 0000 0000 0000 0000b when read.
First error pointer. This 5-bit value reflects the bit position within the secondary
uncorrectable error status register (offset 12Ch, see Section 5.10) corresponding to the
class of the first error condition that was detected.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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5.14 Secondary Header Log Register
The secondary header log register stores the transaction address and command for the PCI bus cycle that
led to the most recently detected error condition. Offset 13Ch accesses register bits 31:0. Offset 140h
accesses register bits 63:32. Offset 144h accesses register bits 95:64. Offset 148h accesses register bits
127:96. See Table 5-12 for a complete description of the register contents.
PCI Express extended register offset:
13Ch, 140h, 144h, and 148h
Register type:
Read-only
Default value:
0000 0000h
BIT NUMBER
RESET STATE
127
0
126
0
125
0
124
0
123
0
122
0
121
0
120
0
119
0
118
0
117
0
116
0
115
0
114
0
113
0
112
0
BIT NUMBER
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 5-12. Secondary Header Log Register Description
BIT
FIELD NAME
127:64 (1) ADDRESS
63:44
RSVD
ACCESS
DESCRIPTION
RU
Transaction address. The 64-bit value transferred on AD[31:0] during the first and second
address phases. The first address phase is logged to 95:64 and the second address phase
is logged to 127:96. In the case of a 32-bit address, bits 127:96 are set to 0.
R
Reserved. Returns 0 0000h when read.
43:40 (1)
UPPER_CMD
RU
Transaction command upper. Contains the status of the C/BE terminals during the second
address phase of the PCI transaction that generated the error if using a dual-address cycle.
39:36 (1)
LOWER_CMD
RU
Transaction command lower. Contains the status of the C/BE terminals during the first
address phase of the PCI transaction that generated the error.
35:0
(1)
106
TRANS_ATTRIBU
TE
R
Transaction attribute. Because the bridge does not support the PCI-X attribute transaction
phase, these bits have no function, and return 0 0000 0000h when read.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
PCI Express Extended Configuration Space
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Memory-Mapped TI Proprietary Register Space
The programming model of the memory-mapped TI proprietary register space is unique to this device.
All bits marked with a I are sticky bits and are reset by a global reset (GRST) or the internally-generated
power-on reset. All bits marked with a (2) are reset by a PCI Express reset (PERST), a GRST or the
internally-generated power-on reset. The remaining register bits are reset by a PCI Express hot reset,
PERST, GRST, or the internally-generated power-on reset.
(2)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Table 6-1. Device Control Memory Window Register Map
REGISTER NAME
OFFSET
Reserved
Revision ID
Device control map ID
Reserved
004h–03Ch
GPIO data (1)
Serial-bus control and status (1)
GPIO control (1)
Serial-bus slave address (1)
Serial IRQ edge control
040h
Serial-bus word address (1)
Serial-bus data (1)
044h
Reserved
Serial IRQ mode
control (1)
048h
(1)
Reserved
Serial IRQ status (1)
Cache Timer Transfer Limit (1)
PFA Request Limit (1)
Cache Timer Upper Limit
(1)
Cache Timer Lower Limit
04Ch
050h
(1)
Reserved
(1)
6.1
000h
054h
058h–FFFh
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Device Control Map ID Register
The device control map ID register identifies the TI proprietary layout for this device control map. The
value 04h identifies this as a PCI Express-to-PCI bridge.
Device control memory window register offset:
00h
Register type:
Read-only
Default value:
BIT NUMBER
RESET STATE
7
0
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6
0
5
0
4
0
3
0
2
1
1
0
0
0
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Revision ID Register
The revision ID register identifies the revision of the TI proprietary layout for this device control map. The
value 00h identifies the revision as the initial layout.
Device control memory window register offset:
01h
Register type:
Read-only
Default value:
00h
BIT NUMBER
RESET STATE
6.3
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
GPIO Control Register
This register controls the direction of the five GPIO terminals. This register has no effect on the behavior
of GPIO terminals that are enabled to perform secondary functions. The secondary functions share GPIO0
(CLKRUN), GPIO1 (PWR_OVRD), GPIO3 (SDA), and GPIO4 (SCL). This register is an alias of the GPIO
control register in the classic PCI configuration space(offset B4h, see Section 4.59). See Table 6-2 for a
complete description of the register contents.
Device control memory window register offset:
40h
Register type:
Read-only, Read/Write
Default value:
0000h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-2. GPIO Control Register Description
BIT
15:5
4
(1)
FIELD NAME
RSVD
GPIO4_DIR
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 0000 0000 000b when read.
GPIO 4 data direction. This bit selects whether GPIO4 is in input or output mode.
0 = Input (default)
1 = Output
3 (1)
GPIO3_DIR
RW
GPIO 3 data direction. This bit selects whether GPIO3 is in input or output mode.
0 = Input (default)
1 = Output
2 (1)
GPIO2_DIR
RW
GPIO 2 data direction. This bit selects whether GPIO2 is in input or output mode.
0 = Input (default)
1 = Output
1 (1)
GPIO1_DIR
RW
GPIO 1 data direction. This bit selects whether GPIO1 is in input or output mode.
0 = Input (default)
1 = Output
0 (1)
GPIO0_DIR
RW
GPIO 0 data direction. This bit selects whether GPIO0 is in input or output mode.
0 = Input (default)
1 = Output
(1)
108
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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GPIO Data Register
This register reads the state of the input mode GPIO terminals and changes the state of the output mode
GPIO terminals. Writing to a bit that is in input mode or is enabled for a secondary function is ignored. The
secondary functions share GPIO0 (CLKRUN), GPIO1 (PWR_OVRD), GPIO3 (SDA), and GPIO4 (SCL).
The default value at power up depends on the state of the GPIO terminals as they default to
general-purpose inputs. This register is an alias of the GPIO data register in the classic PCI configuration
space (offset B6h, see Section 4.60). See Table 6-3 for a complete description of the register contents.
Device control memory window register offset:
42h
Register type:
Read-only, Read/Write
Default value:
00XXh
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
x
3
x
2
x
1
x
0
x
Table 6-3. GPIO Data Register Description
BIT
15:5
4
(1)
FIELD NAME
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 000 0000 0000b when read.
GPIO4_Data
RW
GPIO 4 data. This bit reads the state of GPIO4 when in input mode or changes the state
of GPIO4 when in output mode.
3 (1)
GPIO3_Data
RW
GPIO 3 data. This bit reads the state of GPIO3 when in input mode or changes the state
of GPIO3 when in output mode.
2 (1)
GPIO2_Data
RW
GPIO 2 data. This bit reads the state of GPIO2 when in input mode or changes the state
of GPIO2 when in output mode.
1 (1)
GPIO1_Data
RW
GPIO 1 data. This bit reads the state of GPIO1 when in input mode or changes the state
of GPIO1 when in output mode.
0 (1)
GPIO0_Data
RW
GPIO 0 data. This bit reads the state of GPIO0 when in input mode or changes the state
of GPIO0 when in output mode.
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Serial-Bus Data Register
The serial-bus data register reads and writes data on the serial-bus interface. Write data is loaded into this
register prior to writing the serial-bus slave address register that initiates the bus cycle. When reading data
from the serial bus, this register contains the data read after bit 5 (REQBUSY) in the serial-bus control and
status register (offset 47h, see Section 6.8) is cleared. This register is an alias for the serial-bus data
register in the PCI header (offset B0h, see Section 4.55). This register is reset by a PCI Express reset
(PERST), a GRST, or the internally-generated power-on reset.
Device control memory window register offset:
44h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
6.6
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
1
Serial-Bus Word Address Register
The value written to the serial-bus word address register represents the word address of the byte being
read from or written to on the serial-bus interface. The word address is loaded into this register prior to
writing the serial-bus slave address register that initiates the bus cycle. This register is an alias for the
serial-bus word address register in the PCI header (offset B1h, see Section 4.56). This register is reset by
a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Device control memory window register offset:
45h
Register type:
Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
6.7
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Serial-Bus Slave Address Register
The serial-bus slave address register indicates the address of the device being targeted by the serial-bus
cycle. This register also indicates if the cycle will be a read or a write cycle. Writing to this register initiates
the cycle on the serial interface. This register is an alias for the serial-bus slave address register in the
PCI header (offset B2h, see Section 4.57). See Table 6-4 for a complete description of the register
contents.
Device control memory window register offset:
46h
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
7
0
00h
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-4. Serial-Bus Slave Address Register Descriptions
BIT
7:1 (1)
0 (1)
FIELD NAME
ACCESS
DESCRIPTION
SLAVE_ADDR
RW
Serial-bus slave address. This 7-bit field is the slave address for a serial-bus read or write
transaction. The default value for this field is 000 0000b.
RW_CMD
RW
Read/write command. This bit determines if the serial-bus cycle is a read or a write cycle.
0 = A single byte write is requested (default)
1 = A single byte read is requested
(1)
110
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Memory-Mapped TI Proprietary Register Space
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Serial-Bus Control and Status Register
The serial-bus control and status register controls the behavior of the serial-bus interface. This register
also provides status information about the state of the serial-bus. This register is an alias for the serial-bus
control and status register in the PCI header (offset B3h, see Section 4.58). See Table 6-5 for a complete
description of the register contents.
Device control memory window register offset:
47h
Register type:
Read-only, Read/Write, Read/Clear
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-5. Serial-Bus Control and Status Register Description
BIT
7
(1)
FIELD NAME
PROT_SEL
ACCESS
RW
DESCRIPTION
Protocol select. This bit selects the serial-bus address mode used.
0 = Slave address and word address are sent on the serial-bus (default)
1 = Only the slave address is sent on the serial-bus
6
5 (1)
RSVD
REQBUSY
R
RU
Reserved. Returns 0b when read.
Requested serial-bus access busy. This bit is set when a software-initiated serial-bus cycle
is in progress.
0 = No serial-bus cycle
1 = Serial-bus cycle in progresss
4 (1)
ROMBUSY
RU
Serial EEPROM access busy. This bit is set when the serial EEPROM circuitry in the
bridge is downloading register defaults from a serial EEPROM.
0 = No EEPROM activity
1 = EEPROM download in progress
3 (1)
SBDETECT
RWU
Serial EEPROM detected. This bit enables the serial-bus interface. The value of this bit
controls whether the GPIO3//SDA and GPIO4//SCL terminals are configured as GPIO
signals or as serial-bus signals. This bit is automatically set to 1b when a serial EEPROM
is detected.
Note: A serial EEPROM is only detected once following PERST.
0 = No EEPROM present, EEPROM load process does not happen. GPIO3//SDA and
GPIO4//SCL terminals are configured as GPIO signals.
1 = EEPROM present, EEPROM load process takes place. GPIO3//SDA and
GPIO4//SCL terminals are configured as serial-bus signals.
2 (1)
SBTEST
RW
Serial-bus test. This bit is used for internal test purposes. This bit controls the clock source
for the serial interface clock.
0 = Serial-bus clock at normal operating frequency ~ 60 kHz (default)
1 = Serial-bus clock frequency increased for test purposes ~ 4 MHz
1
(1)
SB_ERR
RCU
Serial-bus error. This bit is set when an error occurs during a software-initiated serial-bus
cycle.
0 = No error
1 = Serial-bus error
0 (1)
ROM_ERR
RCU
Serial EEPROM load error. This bit is set when an error occurs while downloading
registers from a serial EEPROM.
0 = No error
1 = EEPROM load error
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Serial IRQ Mode Control Register
This register controls the behavior of the serial IRQ controller. This register is an alias for the serial IRQ
mode control register in the classic PCI configuration space (offset E0h, see Section 4.72). See
Table 4-46 for a complete description of the register contents.
Device control memory window register
offset:
48h
Register type:
Read-only, Read/Write
Default value:
00h
BIT NUMBER
RESET STATE
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-6. Serial IRQ Mode Control Register Description
BIT
7:4
FIELD NAME
ACCESS
RSVD
R
DESCRIPTION
Reserved. Returns 0h when read.
Start frame pulse width. Sets the width of the start frame for a SERIRQ stream.
00 = 4 clocks (default)
3:2 (1)
START_WIDTH
RW
01 = 6 clocks
10 = 8 clocks
11 = Reserved
Poll mode. This bit selects between continuous and quiet mode.
1 (1)
POLLMODE
RW
0 = Continuous mode (default)
1 = Quiet mode
0 (1)
RW Drive mode. This bit selects the behavior of the serial IRQ controller during the
recovery cycle.
DRIVEMODE
RW
0 = Drive high (default)
1 = 3-state
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
6.10 Serial IRQ Edge Control Register
This register controls the edge mode or level mode for each IRQ in the serial IRQ stream. This register is
an alias for the serial IRQ edge control register in the classic PCI configuration space (offset E2h, see
Section 4.73). See Table 6-7 for a complete description of the register contents.
Device control memory window register 4Ah
offset:
Register type:
Read/Write
Default value:
BIT NUMBER
RESET STATE
112
15
0
0000h
14
0
13
0
12
0
Memory-Mapped TI Proprietary Register Space
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
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Table 6-7. Serial IRQ Edge Control Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 15 edge mode
15 (1)
IRQ15_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 14 edge mode
14 (1)
IRQ14_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 13 edge mode
13 (1)
IRQ13_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 12 edge mode
12 (1)
IRQ12_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 11 edge mode
11 (1)
IRQ11_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 10 edge mode
10 (1)
IRQ10_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 9 edge mode
9 (1)
IRQ9_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 8 edge mode
8 (1)
IRQ8_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 7 edge mode
7 (1)
IRQ7_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 6 edge mode
6 (1)
IRQ6_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 5 edge mode
5 (1)
IRQ5_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 4 edge mode
4 (1)
IRQ4_MODE
RW
0 = Edge mode (default)
1 = Level mode
(1)
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 6-7. Serial IRQ Edge Control Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 3 edge mode
3 (1)
IRQ3_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 2 edge mode
2 (1)
IRQ2_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 1 edge mode
1 (1)
IRQ1_MODE
RW
0 = Edge mode (default)
1 = Level mode
IRQ 0 edge mode
0 (1)
IRQ0_MODE
RW
0 = Edge mode (default)
1 = Level mode
6.11 Serial IRQ Status Register
This register indicates when a level mode IRQ is signaled on the serial IRQ stream. After a level mode
IRQ is signaled, a write-back of 1b to the asserted IRQ status bit re-arms the interrupt. IRQ interrupts that
are defined as edge mode in the serial IRQ edge control register are not reported in this status register.
This register is an alias for the serial IRQ status register in the classic PCI configuration space (offset E4h,
see Section 4.74). See Table 4-48 for a complete description of the register contents.
Device control memory window register
offset:
4Ch
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
0000h
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-8. Serial IRQ Status Register Description
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 15 asserted. This bit indicates that the IRQ15 has been asserted.
15 (1)
IRQ15
RCU
0 = Deasserted
1 = Asserted
IRQ 14 asserted. This bit indicates that the IRQ14 has been asserted.
14 (1)
IRQ14
RCU
0 = Deasserted
1 = Asserted
IRQ 13 asserted. This bit indicates that the IRQ13 has been asserted.
13 (1)
IRQ13
RCU
0 = Deasserted
1 = Asserted
(1)
114
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 6-8. Serial IRQ Status Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 12 asserted. This bit indicates that the IRQ12 has been asserted.
12 (1)
IRQ12
RCU
0 = Deasserted
1 = Asserted
IRQ 11 asserted. This bit indicates that the IRQ11 has been asserted.
11 (1)
IRQ11
RCU
0 = Deasserted
1 = Asserted
IRQ 10 asserted. This bit indicates that the IRQ10 has been asserted.
10 (1)
IRQ10
RCU
0 = Deasserted
1 = Asserted
IRQ 9 asserted. This bit indicates that the IRQ9 has been asserted.
9 (1)
IRQ9
RCU
0 = Deasserted
1 = Asserted
IRQ 8 asserted. This bit indicates that the IRQ8 has been asserted.
8 (1)
IRQ8
RCU
0 = Deasserted
1 = Asserted
IRQ 7 asserted. This bit indicates that the IRQ7 has been asserted.
7 (1)
IRQ7
RCU
0 = Deasserted
1 = Asserted
IRQ 6 asserted. This bit indicates that the IRQ6 has been asserted.
6 (1)
IRQ6
RCU
0 = Deasserted
1 = Asserted
IRQ 5 asserted. This bit indicates that the IRQ5 has been asserted.
5 (1)
IRQ5
RCU
0 = Deasserted
1 = Asserted
IRQ 4 asserted. This bit indicates that the IRQ4 has been asserted.
4 (1)
IRQ4
RCU
0 = Deasserted
1 = Asserted
IRQ 3 asserted. This bit indicates that the IRQ3 has been asserted.
3 (1)
IRQ3
RCU
0 = Deasserted
1 = Asserted
IRQ 2 asserted. This bit indicates that the IRQ2 has been asserted.
2 (1)
IRQ2
RCU
0 = Deasserted
1 = Asserted
IRQ 1 asserted. This bit indicates that the IRQ1 has been asserted.
1 (1)
IRQ1
RCU
0 = Deasserted
1 = Asserted
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Table 6-8. Serial IRQ Status Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
IRQ 0 asserted. This bit indicates that the IRQ0 has been asserted.
0 (1)
IRQ0
RCU
0 = Deasserted
1 = Asserted
6.12 Pre-Fetch Agent Request Limits Register
This register is used to set the Pre-Fetch Agent's limits on retrieving data using upstream reads. This
register is an alias for the pre-fetch agent request limits register in the classic PCI configuration space
(offset E8h, see Section 4.75). See Table 6-9 for a complete description of the register contents.
Device control memory window
register offset:
50h
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
0443h
14
0
13
0
12
0
11
0
10
1
9
0
8
0
7
0
6
1
5
0
4
0
3
0
2
0
1
1
0
1
Table 6-9. Pre-Fetch Agent Request Limits Register Description
BIT
FIELD NAME
15:12
RSVD
ACCESS
R
DESCRIPTION
Reserved. Returns 0h when read.
Request count limit. Determines the number of Pre-Fetch reads that takes place in each
burst.
11:8 (1)
PFA_REQ_
CNT_LIMIT
RW
4'h0 = Auto-prefetch agent is disabled.
4'h1 = Thread is limited to one buffer. No auto-prefetch reads will be generated.
4'h2:F = Thread will be limited to initial read and (PFA_REQ_CNT_LIMIT – 1)
Completion cache mode. Determines the rules for completing the caching process.
00 = No caching.
• Pre-fetching is disabled.
• All remaining read completion data will be discarded after any of the data has been
returned to the PCI master.
7:6
PFA_CPL_CACHE_
MODE
RW
01 = Light caching.
• Pre-fetching is enabled.
• All remaining read completion data will be discarded after data has been returned to
the PCI master and the PCI master terminated the transfer.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the bridge has terminated the transfer with RETRY.
10 = Full caching.
• Pre-fetching is enabled.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the PCI master terminated the transfer.
• All remaining read completion data will be cached after data has been returned to the
PCI master and the bridge has terminated the transfer with RETRY.
11 = Reserved.
5:4
(1)
116
RSVD
R
Reserved. Returns 00b when read.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
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Table 6-9. Pre-Fetch Agent Request Limits Register Description (continued)
BIT
FIELD NAME
ACCESS
DESCRIPTION
Request Length Limit. Determines the number of bytes in the thread that the pre-fetch
agent will read for that thread.
0000 = 64 bytes
0001 = 128 bytes
0010 = 256 bytes
3:0
PFA_REQ_LENGT
H_LIMIT
RW
0011 = 512 bytes
0100 = 1 Kbytes
0101 = 2 Kbytes
0110 = 4 Kbytes
0111 = 8 Kbytes
1000:1111 = Reserved
6.13 Cache Timer Transfer Limit Register
This register is used to set the number of PCI cycle starts that have to occur without a read hit on the
completion data buffer, before the cache data can be discarded. This register is an alias for the pre-fetch
agent request limits register in the classic PCI configuration space (offset EAh, see Section 4.76). See
Table 6-10 for a complete description of the register contents.
Device control memory window register 52h
offset:
Register type:
Read/Clear
Default value:
0008h
BIT NUMBER
RESET STATE
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
1
5
0
4
0
3
1
2
0
1
0
0
0
Table 6-10. Cache Timer Transfer Limit Register Description
BIT
(1)
FIELD NAME
15:8
RSVD
7:0 (1)
CACHE_TMR_XFR
_LIMIT
ACCESS
R
DESCRIPTION
Reserved. Returns 00h when read.
RW
Number of PCI cycle starts that have to occur without a read hit on the completion data
buffer, before the cache data can be discarded.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
6.14 Cache Timer Lower Limit Register
Minimum number of clock cycles that must have passed without a read hit on the completion data buffer
before the "cache miss limit" check can be triggered. See Table 6-11 for a complete description of the
register contents.
Device control memory window
register offset:
54h
Register type:
Read/Clear
Default value:
007Fh
BIT NUMBER
RESET STATE
15
0
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14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
1
5
1
4
1
3
1
2
1
1
1
Memory-Mapped TI Proprietary Register Space
0
1
117
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
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Table 6-11. Cache Timer Lower Limit Register Description
BIT
FIELD NAME
15:12
RSVD
11:0 (1)
CACHE_TIMER
_LOWER_LIMIT
(1)
ACCESS
R
DESCRIPTION
Reserved. Returns 0h when read.
RW
Minimum number of clock cycles that must have passed without a read hit on the
completion data buffer before the "cache miss limit" check can be triggered.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
6.15 Cache Timer Upper Limit Register
Discard cached data after this number of clock cycles have passed without a read hit on the completion
data buffer. See Table 6-12 for a complete description of the register contents.
Device control memory window
register offset:
56h
Register type:
Read/Clear
Default value:
BIT NUMBER
RESET STATE
15
0
01C0h
14
0
13
0
12
0
11
0
10
0
9
0
8
1
7
1
6
1
5
0
4
0
3
0
2
0
1
0
0
0
Table 6-12. Cache Timer Upper Limit Register Description
BIT
FIELD NAME
15:12
RSVD
11:0 (1)
CACHE_TIMER
_UPPER_LIMIT
(1)
118
ACCESS
R
RW
DESCRIPTION
Reserved. Returns 0h when read.
Discard cached data after this number of clock cycles have passed without a read hit on
the completion data buffer.
These bits are reset by a PCI Express reset (PERST), a GRST, or the internally-generated power-on reset.
Memory-Mapped TI Proprietary Register Space
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7
Electrical Characteristics
7.1
Absolute Maximum Ratings
over operating temperature range (unless otherwise noted)
VDD_33
(1)
Supply voltage range
VDD_15
V
V
–0.6 to 0.6
V
–0.5 to VDD_33 + 0.5
V
–0.3 to 1.15
V
Miscellaneous 3.3-V IO
–0.5 to VDD_33 + 0.5
V
PCI
–0.5 to VDD_33 + 0.5
V
PCI Express (TX)
–0.5 to VDD_15 + 0.5
V
Miscellaneous 3.3-V IO
–0.5 to VDD_33 + 0.5
V
±20
mA
±20
mA
–65 to 150
°C
PCI Express REFCLK (single-ended)
PCI Express REFCLK (differential)
VO
Output voltage range
V
–0.5 to 1.65
PCI Express (RX)
Input voltage range
UNIT
–0.5 to PCIR + 0.5
PCI
VI
VALUE
–0.5 to 3.6
Input clamp current, (VI < 0 or VI > VDD) (2)
Output clamp current, (VO < 0 or VO > VDD) (3)
Tstg
(1)
(2)
(3)
Storage temperature range
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Applies for external input and bidirectional buffers. VI < 0 or VI > VDD or VI > PCIR.
Applies for external input and bidirectional buffers. VO < 0 or VO > VDD or VO > PCIR.
7.2
Recommended Operating Conditions
OPERATION
VDD_15
VDDA_15
MIN NOM MAX
UNIT
Supply voltage
1.5 V
1.35
1.5
1.65
V
Supply voltage
3.3 V
3
3.3
3.6
V
3
3.3
3.6
4.75
5
5.25
VDD_33
VDDA_33
VDDA_33_AUX
PCIR
PCI bus clamping rail voltage (with 1 kΩ resistor)
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3.3 V
5V
Electrical Characteristics
V
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7.3
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Nominal Power Consumption
DEVICES
No downstream PCI devices
POWER STATE (1)
VOLTS
AMPERES
WATTS
1.5
0.147
0.221
3.3
0.062
0.205
D0 idle
Totals:
One downstream PCI device
D0 idle
0.209
0.426
1.5
0.148
0.222
3.3
0.077
0.254
Totals:
One downstream PCI device
D0 active
0.225
0.476
1.5
0.157
0.236
3.3
0.165
0.545
0.322
0.780
1.65
0.168
0.277
3.6
0.188
0.677
0.356
0.954
Totals:
One downstream (max voltage)
D0 active
Totals:
(1)
7.4
D0 idle power state: Downstream PCI device is in PCI state D0. Downstream device driver is loaded. Downstream device is not actively
transferring data.
D0 active power state: Downstream PCI device is in PCI state D0. Downstream device driver is loaded. Downstream device is acitvely
transferring data (worst case scenario).
PCI Express Differential Transmitter Output Ranges
PARAMETER
TERMINALS
MIN
UNIT
COMMENTS
400.12
ps
Each UI is 400 ps ±300 ppm. UI does not account for SSC
dictated variations.
0.8
1.2
V
VTX-DIFF-PP = 2*|VTXP – VTXN|
TXP, TXN
0.4
1.2
V
VTX-DIFF-PP = 2*|VTXP – VTXN|
VTX-DE-RATIO-3.5dB
TX de-emphasis level ratio
TXP, TXN
3
4
dB
This is the ratio of the VTX-DIFF-PP of the second and
following bits after a transition divided by the VTX-DIFF-PP of
the first bit after a transition.
TTX-EYE (2) (3) (4)
Minimum TX eye width
TXP, TXN
0.75
UI
Does not include SSC or RefCLK jitter. Includes Rj at 10–12.
TTX-EYE-MEDIAN-to-MAX-JITTER (2)
Maximum time between the jitter median
and maximum deviation from the median
TXP, TXN
UI
Measured differentially at zero crossing points after
applying the 2.5 GT/s clock recovery function.
TTX-RISE-FALL (2)
TX output rise/fall time
TXP, TXN
UI
Measured differentially from 20% to 80% of swing.
MHz
Second order PLL jitter transfer bounding function.
Second order PLL jitter transfer bounding function.
UI (1)
Unit interval
TXP, TXN
399.88
VTX-DIFF-PP
Differential peak-to-peak output voltage
TXP, TXN
VTX-DIFF-PP-LOW
Low-power differential peak-to-peak TX
voltage swing
NOM
400
MAX
0.125
0.125
(5)
BWTX-PLL
Maximum TX PLL bandwidth
TXP, TXN
22
(5) (6)
BWTX-PLL-LO-3DB
Minimum TX PLL bandwidth
TXP, TXN
1.5
MHz
RLTX-DIFF
Tx package plus Si differential return
loss
TXP, TXN
10
dB
RLTX-CM
Tx package plus Si common mode return
loss
TXP, TXN
6
dB
(1)
(2)
(3)
(4)
(5)
(6)
120
Measured over 0.05–1.25 GHz range
SCC permits a 0, –5000 ppm modulation of the clock frequency at a modulation rate not to exceed 33 kHz.
Measurements at 2.5 GT/s require a scope with at least 6.2 GHz bandwidth. 2.5 GT/s may be measured within 200 mils of Tx device's
pins, although deconvolution is recommended.
Transmitter jitter is measured by driving the transmitter under test with a low jitter "ideal" clock and connecting the DUT to a reference
board.
Transmitter raw jitter data must be convolved with a filtering function that represents the worst case CDR tracking BW. After the
convolution process has been applied, the center of the resulting eye must be determined and used as a reference point for obtaining
eye voltage and margins.
The Tx PLL Bandwidth must lie between the min and max ranges given in the above table. PLL peaking must lie below the value listed
above. Note: the PLL B/W extends from zero up to the value(s) specified in the above table.
A single combination of PLL BW and peaking is specified for 2.5 GT/s implemenations.
Electrical Characteristics
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PCI Express Differential Transmitter Output Ranges (continued)
PARAMETER
TERMINALS
MAX
UNIT
120
Ω
TXP, TXN
20
mV
ITX-SHORT
Transmitter short-circuit current limit
TXP, TXN
90
mA
The total current transmitter can supply when shorted to
ground.
VTX-DC-CM
Transmitter DC common-mode voltage
TXP, TXN
0
3.6
V
The allowed DC common-mode voltage at the transmitter
pins under any conditions.
VTX-CM-DC-ACTIVE-IDLE-DELTA
Absolute delta of DC common mode
voltage during L0 and electrical idle
TXP, TXN
0
100
mV
|VTX-CM-DC – VTX-CM-Idle-DC| ≤ 100 mV
VTX-CM-DC = DC(avg) of |VTXP + VTXN|/2 [during L0]
VTX-CM-Idle-DC = DC(avg) of |VTXP + VTXN|/2 [during electrical
idle]
VTX-CM-DC-LINE-DELTA
Absolute delta of DC common mode
voltage between P and N
TXP, TXN
0
25
mV
|VTXP-CM-DC – VTXN-CM-DC| ≤25 mV when
VTXP-CM-DC = DC(avg) of |VTXP| [during L0]
VTXN-CM-DC = DC(avg) of |VTXN| [during L0]
VTX-IDLE-DIFF-AC-p
Electrical idle differential peak output
voltage
TXP, TXN
0
20
mV
VTX-IDLE-DIFFp = |VTXP-Idle – VTXN-Idle| ≤ 20 mV
VTX-RCV-DETECT
The amount of voltage change allowed
during receiver detection
TXP, TXN
600
mV
The total amount of voltage change that a transmitter can
apply to sense whether a low impedance receiver is
present.
TTX-IDLE-MIN
Minimum time spent in electrical idle
TXP, TXN
ns
Minimum time a transmitter must be in electrical idle.
TTX-IDLE-SET-TO-IDLE
Maximum time to transition to a valid
electrical idle after sending an EIOS
TXP, TXN
8
ns
After sending the required number of EIOSs, the
transmitter must meet all electrical idle specifications
within this time. This is measured from the end of the last
EIOS to the transmitter in electrical idle.
TTX-IDLE-TO-DIFF-DATA
Maximum time to transition to a valid diff
signaling after leaving electrical idle
TXP, TXN
8
ns
Maximum time to transistion to valid diff signaling after
leaving electrical idle. This is considered a debounce time
to the Tx.
CTX
AC coupling capacitor
TXP, TXN
200
nF
All transmitters shall be AC coupled. The AC coupling is
required either within the media or within the transmitting
component itself.
ZTX-DIFF_DC
DC differential TX impedance
TXP, TXN
VTX-CM-AC-P (7)
TX AC common mode voltage
(7)
7.5
MIN
NOM
80
20
75
COMMENTS
Low impedance defined during signaling.
Measurement is made over at least 10 UI.
PCI Express Differential Receiver Input Ranges
PARAMETER
TERMINALS
MIN
NOM
MAX
UNIT
COMMENTS
RXP, RXN
399.88
400.12
ps
Each UI is 400 ps ±300 ppm. UI does not account for
SSC dictated variations.
VRX-DIFF-PP-CC
Differential input peak-to-peak voltage
RXP, RXN
0.175
1.200
V
VRX-DIFFp-p = 2*|VRXP – VRXN|
TRX-EYE (2) (3)
Minimum receiver eye width
RXP, RXN
0.4
UI
The maximum interconnect media and transmitter jitter
that can be tolerated by the receiver is derived as
TRX-MAX-JITTER = 1 – TRX-EYE = 0.6 UI
UI
Jitter is defined as the measurement variation of the
crossing points (VRX-DIFFp-p = 0 V) in relation to
recovered TX UI. A recovered TX UI is calculated over
3500 consecutive UIs of sample data. Jitter is
measured using all edges of the 250 consecutive UIs
in the center of the 3500 UIs used for calculating the
TX UI.
UI (1)
Unit interval
(2)
(2) (3)
TRX-EYE-MEDIAN-to-MAX-JITTER
Maximum time between the jitter median
and maximum deviation from the median
(1)
(2)
(3)
RXP, RXN
0.3
No test load is necessarily associated with this value.
Specified at the measurement point and measured over any 250 consecutive UIs. A test load must be used as the RX device when
taking measurements. If the clocks to the RX and TX are not derived from the same reference clock, then the TX UI recovered from
3500 consecutive UIs is used as a reference for the eye diagram.
A TRX-EYE = 0.40 UI provides for a total sum of 0.60 UI deterministic and random jitter budget for the transmitter and interconnect
collected any 250 consecutive UIs. The TRX-EYE-MEDIAN-to-MAX-JITTER specification ensures a jitter distribution in which the
median and the maximum deviation from the median is less than half of the total UI jitter budget collected over any 250 consecutive TX
UIs. It must be noted that the median is not the same as the mean. The jitter median describes the point in time where the number of
jitter points on either side is approximately equal as opposed to the averaged time value. If the clocks to the RX and TX are not derived
from the same reference clock, then the TX UI recovered from 3500 consecutive UIs must be used as the reference for the eye
diagram.
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PCI Express Differential Receiver Input Ranges (continued)
PARAMETER
TERMINALS
MAX
UNIT
22
MHz
Second order PLL jitter transfer bounding function.
MHz
Second order PLL jitter transfer bounding function.
mV
VRX-CM-AC-P = RMS(|VRXP + VRXN|/2 – VRX-CM-DC)
VRX-CM-DC = DC(avg) of |VRXP + VRXN|/2.
10
dB
Measured over 50 MHz to 1.25 GHz with the P and N
lines biased at +300 mV and –300 mV, respectively.
RXP, RXN
6
dB
Measured over 50 MHz to 1.25 GHz with the P and N
lines biased at +300 mV and –300 mV, respectively.
RXP, RXN
80
120
Ω
RX dc differential mode impedance
ZRX-DC
DC input impedance
RXP, RXN
40
60
Ω
Required RXP as well as RXN dc impedance (50
Ω±20% tolerance).
ZRX-HIGH-IMP-DC-POS (7)
DC input CM input impedance for V > 0
during reset or powerdown
RXP, RXN
50
kΩ
Rx DC CM impedance with the Rx terminations not
powered, measured over the range 0 to 200 mV with
respect to ground.
ZRX-HIGH-IMP-DC-NEG (7)
DC input CM input impedance for V > 0
during reset or powerdown
RXP, RXN
1
kΩ
Rx DC CM impedance with the Rx terminations not
powered, measured over the range 0 to 200 mV with
respect to ground.
VRX-IDLE-DET-DIFFp-p
Electrical idle detect threshold
RXP, RXN
65
mV
VRX-IDLE-DET-DIFFp-p = 2*|VRXP – VRXN| measured at the
receiver package terminals
ms
An unexpected electrical idle
(VRX-DIFFp-p < VRX-IDLE-DET-DIFFp-p) must be recognized
no longer than
TRX-IDLE-DET-DIFF-ENTER-TIME to signal an unexpected idle
condition.
BWRX-PLL-HI (4)
Maximum Rx PLL bandwidth
RXP, RXN
BWRX-PLL-LO-3DB (4)
Minimum Rx PLL for 3 dB peaking
RXP, RXN
VRX-CM-AC-P (2)
AC peak common mode input voltage
RXP, RXN
RLRX-DIFF (5)
Differential return loss
RXP, RXN
RLRX-CM (5)
Common mode return loss
ZRX-DIFF-DC (6)
DC differential input impedance
MIN
NOM
1.5
150
(5) (6)
TRX-IDLE-DET-DIFF-ENTER-TIME
Unexpected electrical idle enter detect
threshold integration time
(4)
(5)
(6)
(7)
RXP, RXN
175
10
A single PLL bandwidth and peaking value of 1.5 to 22 MHz and 3 dB are defined.
The receiver input impedance results in a differential return loss greater than or equal to 15 dB with the P line biased to 300 mV and the
N line biased to .300 mV and a common mode return loss greater than or equal to 6 dB (no bias required) over a frequency range of 50
MHz to 1.25 GHz. This input impedance requirement applies to all valid input levels. The reference impedance for return loss
measurements for is 50 . to ground for both the P and N line (i.e., as measured by a Vector Network Analyzer with 50-. probes). The
series capacitors CTX is optional for the return loss measurement.
Impedance during all link training status state machine (LTSSM) states. When transitioning from a PCI Express reset to the detect state
(the initial state of the LTSSM) there is a 5-ms transition time before receiver termination values must be met on the unconfigured lane
of a port.
ZRX-HIGH-IMP-DC-NEG and ZRX-HIGH-IMP-DC-POS are defined respectively for negative and postive voltages at the input of the receiver.
PCI Express Differential Reference Clock Input Ranges (1)
7.6
PARAMETER
TERMINALS
fIN-DIFF
Differential input frequency
REFCLK+
REFCLK–
fIN-SE
Single-ended input
frequency
REFCLK+
VRX-DIFFp-p
Differential input
peak-to-peak voltage
REFCLK+
REFCLK–
REFCLK+
VIH-SE
REFCLK+
VIL-SE
VRX-CM-ACp
AC peak common mode
input voltage
MIN
NOM
MAX
UNIT
COMMENTS
100
MHz
The input frequency is 100 MHz + 300 ppm and –2800
ppm including SSC-dictated variations.
125
MHz
The input frequency is 125 MHz + 300 ppm and –300
ppm.
-0.30
1.150
V
VRX-DIFFp-p = 2*|VREFCLK+ – VREFCLK-|
0.7 VDDA_33
VDDA_33
V
Single-ended, reference clock mode high-level input
voltage
0
0.3 VDDA_33
V
Single-ended, reference clock mode low-level input
voltage
REFCLK+
REFCLK–
140
Duty cycle
REFCLK+
REFCLK–
40%
60%
ZC-DC
Clock source DC impedance
REFCLK+
REFCLK–
40
60
(1)
122
COMMENTS
mV
VRX-CM-ACp = RMS(|VREFCLK+ + VREFCLK-|/2 VRX-CM-DC)
VRX-CM-DC = DC(avg) of
|VREFCLK+ + VREFCLK-|/2
Differential and single-ended waveform input duty
cycle
Ω
REFCLK± dc differential mode impedance
The XIO2001 is compliant with the defined system jitter models for a PCI-Express reference clock and associated TX/RX link. Any
usage of the XIO2001 in a system configuration that does not conform to the defined system jitter models requires the system designer
to validate the system jitter budgets.
Electrical Characteristics
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PCI Express Differential Reference Clock Input Ranges (continued)
PARAMETER
TERMINALS
ZRX-DC
DC input impedance
7.7
MIN
NOM
REFCLK+
REFCLK–
20
PCI Bus Electrical Characteristics
MAX
UNIT
kΩ
COMMENTS
REFCLK+ dc single-ended mode impedance
(1)
over recommended operating conditions
PARAMETER
OPERATION
TEST CONDITIONS
MIN
MAX
0.5 × VDD_33
PCIR + 0.5
2.0
PCIR + 0.5
PCIR = 3.3 V
–0.5
0.3 × VDD_33
PCIR = 5 V
–0.5
0.8
PCIR = 3.3 V
UNIT
VIH
High-level input voltage (2)
VIL
Low-level input voltage
VI
Input voltage
0
PCIR
V
VO
Output voltage (3)
0
VDD_33
V
tt
Input transition time (trise and tfall)
1
4
ns
PCIR = 5 V
(2)
VOH
High-level output voltage
VOL
Low-level output voltage
IOZ
High-impedance, output current (3)
II
Input current
(1)
(2)
(3)
7.8
PCIR = 3.3 V
IOH = –500 µA
PCIR = 5 V
IOH = –2 mA
PCIR = 3.3 V
IOH = 1500 µA
PCIR = 5 V
IOH = 6 mA
0.9 × VDD_33
V
V
V
2.4
0.1 × VDD_33
0.55
PCIR = 3.3 V
±10
PCIR = 5 V
±70
PCIR = 3.3 V
±10
PCIR = 5 V
±70
V
µA
µA
This table applies to CLK, CLKOUT6:0, AD31:0, C/BE[3:0], DEVSEL, FRAME, GNT5:0, INTD:A, IRDY, PAR, PERR, REQ5:0, PRST,
SERR, STOP, TRDY, SERIRQ, M66EN, and LOCK terminals.
Applies to external inputs and bidirectional buffers.
Applies to external outputs and bidirectional buffers.
3.3-V I/O Electrical Characteristics
(1)
over recommended operating conditions
PARAMETER
MIN
MAX
VDD_33
0.7 VDD_33
VDD_33
V
VDD_33
0
0.3 VDD_33
V
Input voltage
0
VDD_33
V
Output voltage (3)
0
VDD_33
V
tt
Input transition time (trise and tfall)
0
25
ns
Vhys
Input hysteresis (4)
0.13 VDD_33
V
VOH
High-level output voltage
VDD_33
IOH = –4 mA
VOL
Low-level output voltage
VDD_33
IOL = 4 mA
IOZ
High-impedance, output current (3)
VDD_33
IOZP
II
VIH
High-level input voltage (2)
VIL
VIL Low-level input voltage
VI
VO
(1)
(2)
(3)
(4)
(5)
OPERATION
(2)
TEST CONDITIONS
0.8 VDD_33
UNIT
V
0.22 VDD_33
V
VI = 0 to VDD_33
±20
µA
High-impedance, output current with internal VDD_33
pullup or pulldown resistor (1)
VI = 0 to VDD_33
±100
µA
Input current (5)
VI = 0 to VDD_33
±1
µA
VDD_33
Applies to GRST (pullup), EXT_ARB_EN (pulldown), CLKRUN_EN (pulldown), and most GPIO (pullup).
Applies to external inputs and bidirectional buffers.
Applies to external outputs and bidirectional buffers.
Applies to PERST, GRST, and PME.
Applies to external input buffers.
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PCI Bus Timing Requirements (1)
7.9
over recommended operating conditions
PARAMETER
TEST CONDITION
CLK to shared signal valid propagation delay time
tpd
CLK to shared signal invalid propagation delay time
33 MHz
MIN
CL = 50 pF
66 MHz
MAX
MIN
UNIT
11
CL = 30 pF
CL = 50 pF
MAX
6
2
CL = 30 pF
ns
1
tON
tEnable time, high-impedance-to-active delay time
from CLK
CL = 50 pF
tOFF
Disable time, active-to-high-impedance delay time
from CLK
CL = 50 pF
tsu
Setup time on shared signals before CLK valid
(rising edge)
7
3
ns
th
Hold time on shared signals after CLK valid (rising
edge)
0
0
ns
(1)
CL = 30 pF
PARAMETER
Junction-to-free-air thermal
resistance
14
TEST CONDITIONS
MIN
TYP
Low-K JEDEC test board, 1s (single signal layer), no air
flow
ns
Junction-to-case thermal resistance
Cu cold plate measurement process
θJB
Junction-to-board thermal
resistance
ψJT
ψJB
TA
MAX
UNIT
85
°C/W
High-K JEDEC test board, 2s2p (double signal layer,
double buried power plane), no air flow
θJC
124
28
CL = 30 pF
ZGU Thermal Characteristics (1)
θJA
(1)
ns
1
The PCI shared signals are AD31:0, C/BE[3:0], FRAME, TRDY, IRDY, STOP, IDSEL, DEVSEL, LOCK, SERIRQ, PAR, PERR, SERR,
and CLKRUN.
7.10
TJ
2
48.3
8.5
°C/W
EIA/JESD 51-8
25.4
°C/W
Junction-to-top of package
EIA/JESD 51-2
0.5
°C/W
Junction-to-board
EIA/JESD 51-6
24
°C/W
Operating ambient temperature
range
XIO2001ZGU
0
70
XIO2001IZGU
–40
85
XIO2001ZGU
0
105
XIO2001IZGU
–40
105
Virtual junction temperature
°C
°C
For more details, refer to TI application note IC Package Thermal Metrics (SPRA953).
Electrical Characteristics
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SCPS212B – MAY 2009 – REVISED JULY 2009
7.11 Parameter Measurement Information
PCI Bus
LOAD CIRCUIT PARAMETERS
TIMING
PARAMETER
tPZH
ten
tPZL
tPHZ
tdis
tPLZ
tpd
CLOAD†
(pF)
IOL
(mA)
IOH
(mA)
VLOAD
(V)
30/50
12
- 12
0
3
30/50
12
- 12
1.5
30/50
12
- 12
‡
IOL
From Output
Under Test
Test
Point
VLOAD
CLOAD
† CLOAD includes the typical load-circuit distributed capacitance.
IOH
‡ VLOAD - VOL = 50 Ω, where V
OL = 0.6 V, IOL = 12 mA
IOL
LOAD CIRCUIT
VDD
Timing
Input
(see Note A )
Data
Input
50% VDD
0V
tsu
90% VDD
10% VDD
High-Level
Input
50% VDD
50% VDD
0V
th
tw
VDD
50% VDD
50% VDD
tr
0V
tf
Low-Level
Input
VDD
50% VDD
VDD
Output
Control
(low-level
enabling)
50% VDD
tPLZ
tpd
tpd
50% VDD
tpd
Out-of-Phase
Output
50% VDD
0V
tPZL
50% VDD
0V
In-Phase
Output
VDD
50% VDD
0V
50% VDD
VOLTAGE WAVEFORMS
PULSE DURATION
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
INPUT RISE AND FALL TIMES
Input
(see Note A)
VDD
50% VDD
VOH
50% VDD
VOL
tpd
VOH
50% VDD
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
Waveform 1
(see Note B)
50% VDD
tPHZ
tPZH
Waveform 2
(see Note B)
50% VDD
VDD
≈ 50% VDD
VOL + 0.3 V
VOL
VOH
VOH - 0.3 V
≈ 50% VDD
0V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
A.
Phase relationships between waveforms were chosen arbitrarily. All input pulses are supplied by pulse generators
having the following characteristics: PRR = 1 MHz, ZO = 50 Ω, tr ≤ 6 ns, tf ≤ 6 ns.
B.
Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output
control. Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the
output control.
C.
For tPLZ and tPHZ, VOL and VOH are measured values.
Figure 7-1. Load Circuit And Voltage Waveforms
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Electrical Characteristics
125
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
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twH
twL
2V
2 V min Peak-to-Peak
0.8 V
tfall
trise
tc
Figure 7-2. CLK Timing Waveform
CLK
tw
PRST
tsu
Figure 7-3. PRST Timing Waveforms
CLK
1.5 V
tpd
tpd
1.5 V
PCI Output
Valid
ton
PCI Input
toff
Valid
tsu
th
Figure 7-4. Shared Signals Timing Waveforms
8
126
Glossary
ACRONYM
DEFINTION
BIST
Built-in slef test
ECRC
End-to-end cyclic redundancy code
EEPROM
Electrically erasable programmable read-only memory
GP
General purpose
GPIO
General-purpose input output
ID
Identification
IF
Interface
IO
Input output
I2S
Inter IC sound
LPM
Link power management
Glossary
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LSB
Least significant bit
MSB
Most significant bit
MSI
Message signaled interrupts
PCI
Peripheral component interface
PME
PCI power management event
QoS
Quality-of-service
RX
Receive
SCL
Serial-bus clock
SDA
Serial-bus data
TC
Traffic class
TLP
Transaction layer packet or protocol
TX
Transmit
VC
Virtual channel
WRR
Weighted round-robin
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Glossary
127
XIO2001 PCI Express™ to PCI Bus Translation Bridge
SCPS212B – MAY 2009 – REVISED JULY 2009
9
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Mechanical Data
The XIO2001/XIO2001I devices are available in the 144–ball lead–free (Pb atomic number 82) Microstar
BGA package (ZAJ), or the 169-ball lead-free (Pb atomic number 82) MicroStar BGA package (ZGU). The
following figures show the mechanical dimensions for the packages.
128
Mechanical Data
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