Texas Instruments PCI2050GHK, PCI2050PDV Datasheet

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1999 PCIBus Solutions

Data Manual

Printed in U.S.A., 12/99 SCPS053

PCI2050

PCI-to-PCI Bridge

Data Manual

Literature Number: SCPS053

December 1999

Printed on Recycled Paper

IMPORTANT NOTICE

Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements.

CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUIT ABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER’S RISK.

In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.

iii

Contents

Section Title Page

1 Introduction 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 Description 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Features 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.3 Related Documents 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.4 Ordering Information 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 Terminal Descriptions 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 Feature/Protocol Descriptions 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.1 Introduction to the PCI2050 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2 PCI Commands 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3 Configuration Cycles 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4 Special Cycle Generation 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5 Secondary Clocks 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.6 Bus Arbitration 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.6.1 Primary Bus Arbitration 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.6.2 Internal Secondary Bus Arbitration 3–5. . . . . . . . . . . . . . . . . . . .

3.6.3 External Secondary Bus Arbitration 3–6. . . . . . . . . . . . . . . . . . .

3.7 Decode Options 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.8 System Error Handling 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.8.1 Posted Write Parity Error 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.8.2 Posted Write Timeout 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.8.3 Target Abort on Posted Writes 3–6. . . . . . . . . . . . . . . . . . . . . . . .

3.8.4 Master Abort on Posted Writes 3–7. . . . . . . . . . . . . . . . . . . . . . .

3.8.5 Master Delayed Write Timeout 3–7. . . . . . . . . . . . . . . . . . . . . . . .

3.8.6 Master Delayed Read Timeout 3–7. . . . . . . . . . . . . . . . . . . . . . .

3.8.7 Secondary SERR 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.9 Parity Handling and Parity Error Reporting 3–7. . . . . . . . . . . . . . . . . . . . . .

3.9.1 Address Parity Error 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.9.2 Data Parity Error 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.10 Master and Target Abort Handling 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.11 Discard Timer 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.12 Delayed Transactions 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.13 Mode Selection 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.14 Compact PCI Hot-Swap Support 3–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.15 JTAG Support 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.15.1 Test Port Instructions 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.16 GPIO Interface 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.16.1 Secondary Clock Mask 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.16.2 Transaction Forwarding Control 3–15. . . . . . . . . . . . . . . . . . . . . . .

3.17 PCI Power Management 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.17.1 Behavior in Low Power States 3–15. . . . . . . . . . . . . . . . . . . . . . . .

4 Bridge Configuration Header 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.1 Vendor ID Register 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.2 Device ID Register 4–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.3 Command Register 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.4 Status Register 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.5 Revision ID Register 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.6 Class Code Register 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.7 Cache Line Size Register 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.8 Primary Latency Timer Register 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.9 Header Type Register 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.10 BIST Register 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.11 Base Address Register 0 4–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.12 Base Address Register 1 4–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.13 Primary Bus Number Register 4–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.14 Secondary Bus Number Register 4–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.15 Subordinate Bus Number Register 4–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.16 Secondary Bus Latency Timer Register 4–8. . . . . . . . . . . . . . . . . . . . . . . .

4.17 I/O Base Register 4–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.18 I/O Limit Register 4–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.19 Secondary Status Register 4–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.20 Memory Base Register 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.21 Memory Limit Register 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.22 Prefetchable Memory Base Register 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . .

4.23 Prefetchable Memory Limit Register 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . .

4.24 Prefetchable Base Upper 32 Bits Register 4–12. . . . . . . . . . . . . . . . . . . . . .

4.25 Prefetchable Limit Upper 32 Bits Register 4–13. . . . . . . . . . . . . . . . . . . . . .

4.26 I/O Base Upper 16 Bits Register 4–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.27 I/O Limit Upper 16 Bits Register 4–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.28 Capability Pointer Register 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.29 Expansion ROM Base Address Register 4–14. . . . . . . . . . . . . . . . . . . . . . . .

4.30 Interrupt Line Register 4–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.31 Interrupt Pin Register 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.32 Bridge Control Register 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Extension Registers 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.1 Chip Control Register 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.2 Extended Diagnostic Register 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.3 Arbiter Control Register 5–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.4 P_SERR Event Disable Register 5–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.5 GPIO Output Data Register 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.6 GPIO Output Enable Register 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.7 GPIO Input Data Register 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.8 Secondary Clock Control Register 5–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.9 P_SERR Status Register 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.10 PM Capability ID Register 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.11 PM Next Item Pointer Register 5–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.12 Power Management Capabilities Register 5–9. . . . . . . . . . . . . . . . . . . . . .

5.13 Power Management Control/Status Register 5–10. . . . . . . . . . . . . . . . . . . .

5.14 PMCSR Bridge Support Register 5–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.15 Data Register 5–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.16 HS Capability ID Register 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.17 HS Next Item Pointer Register 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.18 Hot Swap Control Status Register 5–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.1 Absolute Maximum Ratings Over Operating Temperature Ranges 6–1.

6.2 Recommended Operating Conditions 6–2. . . . . . . . . . . . . . . . . . . . . . . . . .

6.3 Recommended Operating Conditions for PCI Interface 6–2. . . . . . . . . . .

6.4 Electrical Characteristics Over Recommended Operating Conditions 6–3

6.5 PCI Clock/Reset Timing Requirements Over Recommended Ranges Of Supply Voltage And Operating Free-Air Temperature 6–4. . .

6.6 PCI Timing Requirements Over Recommended Ranges Of

Supply Voltage And Operating Free-Air Temperature 6–5. . . . . . . . . . . . .

6.7 Parameter Measurement Information 6–6. . . . . . . . . . . . . . . . . . . . . . . . . .

6.8 PCI Bus Parameter Measurement Information 6–7. . . . . . . . . . . . . . . . . . .

7 Mechanical Data 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Illustrations

Figure Title Page

2–1 PCI2050 Terminal Diagram 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–1 System Block Diagram 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–2 PCI AD31–AD0 During Address Phase of a Type 0 Configuration Cycle 3–2 3–3 PCI AD31–AD0 During Address Phase of a Type 1 Configuration Cycle 3–3

3–4 Bus Hierarchy and Numbering 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–5 Secondary Clock Block Diagram 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–6 Clock Mask Read Timing After Reset 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–1 Load Circuit and Voltage Waveforms 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–2 PCLK Timing Waveform 6–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–3 RSTIN

Timing Waveforms 6–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–4 Shared-Signals Timing Waveforms 6–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii

List of Tables

Table Title Page

2–1 208-Terminal PDV Signal Names Sorted by Terminal Number 2–2. . . . . . . .

2–2 Signal Names Sorted Alphabetically 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–3 208-Terminal GHK Signal Names Sorted by Terminal Number 2–6. . . . . . . .

2–4 Primary PCI System 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–5 Primary PCI Address and Data 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–6 Primary PCI Interface Control 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–7 Secondary PCI System 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–8 Secondary PCI Address and Data 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–9 Secondary PCI Interface Control 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–10 Miscellaneous Terminals 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–11 JTAG Interface Terminals 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–12 Power Supply 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–1 PCI Command Definition 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–2 PCI S_AD31–S_AD16 During the Address Phase of a Type 0

Configuration Cycle 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–3 Configuration Via MS0 and MS1 3–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–4 JTAG Instructions and Op Codes 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–5 Boundary Scan Terminal Order 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–6 Clock Mask Data Format 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1 Bridge Configuration Header 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–2 Command Register 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–3 Status Register 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–4 Secondary Status Register 4–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–5 Bridge Control Register 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–1 Chip Control Register 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–2 Extended Diagnostic Register 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–3 Arbiter Control Register 5–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–4 P_SERR Event Disable Register 5–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–5 GPIO Output Data Register 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–6 GPIO Output Enable Register 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–7 GPIO Input Data Register 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–8 Secondary Clock Control Register 5–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–9 P_SERR Status Register 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–10 Power Management Capabilities Register 5–9. . . . . . . . . . . . . . . . . . . . . . . . . .

5–11 Power Management Control/Status Register 5–10. . . . . . . . . . . . . . . . . . . . . . .

5–12 PMCSR Bridge Support Register 5–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–13 Hot Swap Control Status Register 5–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

viii

1–1

1 Introduction

1.1 Description

The Texas Instruments PCI2050 PCI-to-PCI bridge provides a high performance connection path between two peripheral component interconnect (PCI) buses. Transactions occur between masters on one PCI bus and targets on another PCI bus, and the PCI2050 allows bridged transactions to occur concurrently on both buses. The bridge supports burst-mode transfers to maximize data throughput, and the two bus traffic paths through the bridge act independently.

The PCI2050 bridge is compliant with the

PCI Local Bus Specification

, and can be used to overcome the electrical loading limits of 10 devices per PCI bus and one PCI device per expansion slot by creating hierarchical buses. The PCI2050 provides two-tier internal arbitration for up to nine secondary bus masters and may be implemented with an external secondary PCI bus arbiter.

The compact-PCI hot-swap extended PCI capability is provided which makes the PCI2050 an ideal solution for multifunction compact PCI cards and adapting single function cards to hot-swap compliance.

The PCI2050 bridge is compliant with the

PCI-to-PCI Bridge Specification 1.1

. The PCI 2050 provides compliance

for

PCI Power Management 1.0 and 1.1

. The PCI2050 has been designed to lead the industry in power conservation. An advanced CMOS process is used to achieve low system power consumption while operating at PCI clock rates up to 33 MHz.

1.2 Features

The PCI2050 supports the following features:

• Configurable for

PCI Bus Power Management Interface Specification

• Provides compact PCI hot-swap functionality

• 3.3-V core logic with universal PCI interfaces compatible with 3.3-V and 5-V PCI signaling environments

• Two 32-bit, 33-MHz PCI buses

• Provides internal two-tier arbitration for up to nine secondary bus masters and supports an external

secondary bus arbiter

• Burst data transfers with pipeline architecture to maximize data throughput in both directions

• Independent read and write buffers for each direction

• Up to three delayed transactions in both directions

• Provides 10 secondary PCI clock outputs

• Predictable latency per

PCI Local Bus Specification

• Propagates bus locking

• Secondary bus is driven low during reset

• Provides VGA/palette memory and I/O, and subtractive decoding options

• Advanced submicron, low-power CMOS technology

• Packaged in 208-terminal QFP or 209-terminal MicroStar BGA

1–2

1.3 Related Documents

•

Advanced Configuration and Power Interface (ACPI) Specification (Revision 1.0)

•

PCI Local Bus Specification (Revision 2.2)

•

PCI-to-PCI Bridge Architecture Specification (Revision 1.1)

•

PCI Bus Power Management Interface Specification (Revision 1.1)

•

PICMG Compact-PCI Hot Swap Specification (Revision 1.0)

1.4 Ordering Information

ORDERING NUMBER NAME VOLTAGE PACKAGE

PCI2050 PCI–PCI Bridge 3.3 V, 5-V Tolerant I/Os 208-terminal QFP

209-terminal MicroStar BGA

2–1

2 Terminal Descriptions

P_AD19

TMS

P_AD11

P_TRDY

S_CLKOUT0

S_GNT8

S_GNT5

S_GNT0

S_REQ1

S_REQ2

S_REQ3

S_REQ5

S_REQ8

S_GNT1

S_GNT2

S_GNT3

S_GNT4

S_GNT6

S_GNT7

GND

S_CLK

S_RST

S_CFN

HSSWITCH/GPIO3

GPIO2

GPIO0

S_CLKOUT1

S_CLKOUT2

S_CLKOUT5

S_CLKOUT4

S_CLKOUT8

P_RST

BPCCE

P_CLK

P_GNT

P_AD30

P_REQ

GND

P_AD31

GND

GPIO1

S_CLKOUT3

S_CLKOUT7

S_CLKOUT9

S_AD13

S_AD15

S_C/BE1

S_SERR

GND

S_LOCK

S_PERR

GND

S_TRDY

S_FRAME

S_C/BE2

GND

S_AD16

S_AD19

S_IRDY

S_AD17

S_AD22

GND

S_C/BE3

S_AD24

S_AD25

GND

S_AD27

S_AD30

GND

S_AD31

S_REQ0

GND NC GND P_AD12 P_AD13

P_C/BE1

P_AD14 GND P_AD15

P_PAR P_SERR

P_LOCK

P_STOP P_DEVSEL

P_IRDY P_FRAME

P_C/BE2 GND P_AD16 P_AD17

P_AD18 GND

P_AD20

P_AD22 P_AD23 GND

P_AD21

P_AD24

P_IDSEL

V P_AD25 P_AD26 GND P_AD27 P_AD28

P_AD29 GND

158

157

160

159

162

161

164

163

166

165

168

167

170

169

172

171

174

173

176

175

178

177

180

179

182

181

184

183

186

185

188

187

190

189

192

191

194

193

196

195

198

197

200

199

202

201

204

203

206

205

208

207

103

104

101

102

100

P_PERR

P_AD10

214365871091211141316151817201922212423262528273029323134333635383740394241444346454847504952

51 106

105

108

107

110

109

112

111

114

113

116

115

118

117

120

119

122

121

124

123

126

125

128

127

130

129

132

131

134

133

136

135

138

137

140

139

142

141

144

143

146

145

148

147

150

149

152

151

154

153

156

155

GND

S_M66ENA

S_AD10

S_AD9

S_C/BE0

S_AD8

S_AD7

S_AD6

GND

S_AD5

S_AD2

S_AD3

S_AD0

S_AD1

GND

TCLK

TRST

TDO

HSLED

GND

MSK_IN

HSENUM

GND

P_V

P_AD1

P_AD0

P_AD2

P_AD4

P_AD5

P_AD7

P_AD3

P_AD8

P_C/BE0

P_AD9

MS1

S_PAR

S_AD18

S_AD20 S_AD21

S_AD26

S_REQ4

MS0

GND

S_AD11

GND

S_AD12

S_AD23

S_AD29

PCI2050

PDV LOW-PROFILE QUAD FLAT PACKAGE

TOP VIEW

S_REQ6

S_REQ7

GND

S_CLKOUT6

P_C/BE3

GND

P_AD6

GND

CCP

TDI

S_V

CCP

S_AD4

GND

S_AD14

S_STOP

S_DEVSEL

GND

S_AD28

Figure 2–1. PCI2050 Terminal Diagram

2–2

T able 2–1. 208-Terminal PDV Signal Names Sorted by Terminal Number

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

1 D1 V

44 P2 BPCCE 87 V12 P_LOCK 130 K17 TDO

2 E3 S_REQ1 45 N5 P_CLK 88 U12 P_PERR 131 K15 V

3 F5 S_REQ2 46 P3 P_GNT 89 P12 P_SERR 132 K14 TMS 4 G6 S_REQ3 47 R1 P_REQ 90 R12 P_PAR 133 J19 TCLK 5 E2 S_REQ4 48 P6 GND 91 W13 V

134 J18 TRST

6 E1 S_REQ5 49 R2 P_AD31 92 V13 P_C/BE1 135 J17 S_V

CCP

7 F3 S_REQ6 50 P5 P_AD30 93 U13 P_AD15 136 J14 GND 8 F2 S_REQ7 51 R3 V

94 P13 GND 137 J15 S_AD0

9 G5 S_REQ8 52 T1 GND 95 W14 P_AD14 138 H19 S_AD1

10 F1 S_GNT0 53 W4 V

96 V14 P_AD13 139 H18 V

11 H6 S_GNT1 54 U5 GND 97 R13 V

140 H17 S_AD2 12 G3 GND 55 R6 P_AD29 98 U14 P_AD12 141 H14 S_AD3 13 G2 S_GNT2 56 P7 V

99 W15 P_AD11 142 H15 GND 14 G1 S_GNT3 57 V5 P_AD28 100 P14 GND 143 G19 S_AD4 15 H5 S_GNT4 58 W5 P_AD27 101 V15 P_AD10 144 G18 S_AD5 16 H3 S_GNT5 59 U6 GND 102 R14 NC 145 G17 V

17 H2 S_GNT6 60 V6 P_AD26 103 U15 V

146 G14 S_AD6 18 H1 S_GNT7 61 R7 P_AD25 104 W16 GND 147 F19 S_AD7 19 J1 S_GNT8 62 W6 V

105 T19 V

148 F18 GND 20 J2 GND 63 P8 P_AD24 106 R17 MS1 149 G15 S_C/BE0 21 J3 S_CLK 64 U7 P_C/BE3 107 P15 P_AD9 150 F17 S_AD8 22 J5 S_RST 65 V7 P_IDSEL 108 N14 V

151 E19 V

23 J6 S_CFN 66 W7 GND 109 R18 P_AD8 152 F14 S_AD9 24 K1 HSSWITCH/GPIO3 67 R8 P_AD23 110 R19 P_C/BE0 153 E18 S_M66ENA 25 K2 GPIO2 68 U8 P_AD22 111 P17 GND 154 F15 S_AD10 26 K3 V

69 V8 V

112 P18 P_AD7 155 E17 MS0 27 K5 GPIO1 70 W8 P_AD21 113 N15 P_AD6 156 D19 GND 28 K6 GPIO0 71 W9 P_AD20 114 P19 V

157 A16 V

29 L1 S_CLKOUT0 72 V9 GND 115 M14 P_AD5 158 C15 GND 30 L2 S_CLKOUT1 73 U9 P_AD19 116 N17 P_AD4 159 E14 S_AD11 31 L3 GND 74 R9 P_AD18 117 N18 GND 160 F13 GND 32 L6 S_CLKOUT2 75 P9 V

118 N19 P_AD3 161 B15 S_AD12 33 L5 S_CLKOUT3 76 W10 P_AD17 119 M15 P_AD2 162 A15 S_AD13 34 M1 V

77 V10 P_AD16 120 M17 V

163 C14 V

35 M2 S_CLKOUT4 78 U10 GND 121 M18 P_AD1 164 B14 S_AD14 36 M3 S_CLKOUT5 79 R10 P_C/BE2 122 M19 P_AD0 165 E13 S_AD15 37 M6 GND 80 P10 P_FRAME 123 L19 GND 166 A14 GND 38 M5 S_CLKOUT6 81 W11 V

124 L18 P_V

CCP

167 F12 S_C/BE1 39 N1 S_CLKOUT7 82 V11 P_IRDY 125 L17 NC 168 C13 S_PAR 40 N2 V

83 U11 P_TRDY 126 L15 MSK_IN 169 B13 S_SERR

41 N3 S_CLKOUT8 84 P11 P_DEVSEL 127 L14 HSENUM 170 A13 V

42 N6 S_CLKOUT9 85 R11 P_STOP 128 K19 HSLED 171 E12 S_PERR 43 P1 P_RST 86 W12 GND 129 K18 TDI 172 C12 S_LOCK

2–3

T able 2–1. 208-Terminal PDV Signal Names Sorted by Terminal Number (continued)

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

173 B12 S_STOP 182 C10 S_AD16 191 B8 S_AD22 200 B6 S_AD27 174 A12 GND 183 E10 S_AD17 192 C8 S_AD23 201 E7 S_AD28 175 A11 S_DEVSEL 184 F10 V

193 F8 GND 202 C6 V

176 B11 S_TRDY 185 A9 S_AD18 194 E8 S_C/BE3 203 A5 S_AD29 177 C11 S_IRDY 186 B9 S_AD19 195 A7 S_AD24 204 F6 S_AD30 178 E11 V

187 C9 GND 196 B7 V

205 B5 GND 179 F11 S_FRAME 188 F9 S_AD20 197 C7 S_AD25 206 E6 S_AD31 180 A10 S_C/BE2 189 E9 S_AD21 198 F7 S_AD26 207 C5 S_REQ0 181 B10 GND 190 A8 V

199 A6 GND 208 A4 V

2–4

Table 2–2. Signal Names Sorted Alphabetically

SIGNAL NAME

PDV NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

BPCCE 44 P2 P_AD0 122 M19 P_PAR 90 R12 S_C/BE3 194 E8 GND 12 G3 P_AD1 121 M18 P_PERR 88 U12 S_CFN 23 J6 GND 20 J2 P_AD2 119 M15 P_REQ 47 R1 S_CLK 21 J3 GND 31 L3 P_AD3 118 N19 P_RST 43 P1 S_CLKOUT0 29 L1 GND 37 M6 P_AD4 116 N17 P_SERR 89 P12 S_CLKOUT1 30 L2 GND 48 P6 P_AD5 115 M14 P_ST OP 85 R11 S_CLKOUT2 32 L6 GND 52 T1 P_AD6 113 N15 P_TRDY 83 U11 S_CLKOUT3 33 L5 GND 54 U5 P_AD7 112 P18 P_V

CCP

124 L18 S_CLKOUT4 35 M2 GND 59 U6 P_AD8 109 R18 S_AD0 137 J15 S_CLKOUT5 36 M3 GND 66 W7 P_AD9 107 P15 S_AD1 138 H19 S_CLKOUT6 38 M5 GND 72 V9 P_AD10 101 V15 S_AD2 140 H17 S_CLKOUT7 39 N1 GND 78 U10 P_AD11 99 W15 S_AD3 141 H14 S_CLKOUT8 41 N3 GND 86 W12 P_AD12 98 U14 S_AD4 143 G19 S_CLKOUT9 42 N6 GND 94 P13 P_AD13 96 V14 S_AD5 144 G18 S_DEVSEL 175 A11 GND 100 P14 P_AD14 95 W14 S_AD6 146 G14 S_FRAME 179 F11 GND 104 W16 P_AD15 93 U13 S_AD7 147 F19 S_GNT0 10 F1 GND 111 P17 P_AD16 77 V10 S_AD8 150 F17 S_GNT1 11 H6 GND 117 N18 P_AD17 76 W10 S_AD9 152 F14 S_GNT2 13 G2 GND 123 L19 P_AD18 74 R9 S_AD10 154 F15 S_GNT3 14 G1 GND 136 J14 P_AD19 73 U9 S_AD11 159 E14 S_GNT4 15 H5 GND 142 H15 P_AD20 71 W9 S_AD12 161 B15 S_GNT5 16 H3 GND 148 F18 P_AD21 70 W8 S_AD13 162 A15 S_GNT6 17 H2 GND 156 D19 P_AD22 68 U8 S_AD14 164 B14 S_GNT7 18 H1 GND 158 C15 P_AD23 67 R8 S_AD15 165 E13 S_GNT8 19 J1 GND 160 F13 P_AD24 63 P8 S_AD16 182 C10 S_IRDY 177 C11 GND 166 A14 P_AD25 61 R7 S_AD17 183 E10 S_LOCK 172 C12 GND 174 A12 P_AD26 60 V6 S_AD18 185 A9 S_M66ENA 153 E18 GND 181 B10 P_AD27 58 W5 S_AD19 186 B9 S_PAR 168 C13 GND 187 C9 P_AD28 57 V5 S_AD20 188 F9 S_PERR 171 E12 GND 193 F8 P_AD29 55 R6 S_AD21 189 E9 S_REQ0 207 C5 GND 199 A6 P_AD30 50 P5 S_AD22 191 B8 S_REQ1 2 E3 GND 205 B5 P_AD31 49 R2 S_AD23 192 C8 S_REQ2 3 F5 GPIO0 28 K6 P_C/BE0 110 R19 S_AD24 195 A7 S_REQ3 4 G6 GPIO1 27 K5 P_C/BE1 92 V13 S_AD25 197 C7 S_REQ4 5 E2 GPIO2 25 K2 P_C/BE2 79 R10 S_AD26 198 F7 S_REQ5 6 E1 HSENUM 127 L14 P_C/BE3 64 U7 S_AD27 200 B6 S_REQ6 7 F3 HSLED 128 K19 P_CLK 45 N5 S_AD28 201 E7 S_REQ7 8 F2 HSSWITCH/GPIO3 24 K1 P_DEVSEL 84 P11 S_AD29 203 A5 S_REQ8 9 G5 MS0 155 E17 P_FRAME 80 P10 S_AD30 204 F6 S_RST 22 J5 MS1 106 R17 P_GNT 46 P3 S_AD31 206 E6 S_SERR 169 B13 MSK_IN 126 L15 P_IDSEL 65 V7 S_C/BE0 149 G15 S_STOP 173 B12 NC 102 R14 P_IRDY 82 V11 S_C/BE1 167 F12 S_TRDY 176 B11 NC 125 L17 P_LOCK 87 V12 S_C/BE2 180 A10 S_V

CCP

135 J17

2–5

Table 2–2. Signal Names Sorted Alphabetically (continued)

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

SIGNAL NAME

PDV

NO.

GHK

NO.

TCLK 133 J19 V

51 R3 V

103 U15 V

157 A16

TDI 129 K18 V

53 W4 V

105 T19 V

163 C14

TDO 130 K17 V

56 P7 V

108 N14 V

170 A13

TMS 132 K14 V

62 W6 V

114 P19 V

178 E11

TRST 134 J18 V

69 V8 V

120 M17 V

184 F10

1 D1 V

75 P9 V

131 K15 V

190 A8

26 K3 V

81 W11 V

139 H18 V

196 B7

34 M1 V

91 W13 V

145 G17 V

202 C6

40 N2 V

97 R13 V

151 E19 V

208 A4

2–6

Table 2–3. 209-Terminal GHK Signal Names Sorted by Terminal Number

GHK

NO.

SIGNAL NAME

GHK

NO.

SIGNAL NAME

GHK

NO.

SIGNAL NAME

GHK

NO.

SIGNAL NAME

GHK

NO.

SIGNAL NAME

A4 V

E9 S_AD21 H17 S_AD2 N1 S_CLKOUT7 T19 V

A5 S_AD29 E10 S_AD17 H18 V

N2 V

U5 GND

A6 GND E11 V

H19 S_AD1 N3 S_CLKOUT8 U6 GND A7 S_AD24 E12 S_PERR J1 S_GNT8 N5 P_CLK U7 P_C/BE3 A8 V

E13 S_AD15 J2 GND N6 S_CLKOUT9 U8 P_AD22

A9 S_AD18 E14 S_AD11 J3 S_CLK N14 V

U9 P_AD19 A10 S_C/BE2 E17 MS0 J5 S_RST N15 P_AD6 U10 GND A11 S_DEVSEL E18 S_M66ENA J6 S_CFN N17 P_AD4 U11 P_TRDY A12 GND E19 V

J14 GND N18 GND U12 P_PERR

A13 V

F1 S_GNT0 J15 S_AD0 N19 P_AD3 U13 P_AD15

A14 GND F2 S_REQ7 J17 S_V

CCP

P1 P_RST U14 P_AD12

A15 S_AD13 F3 S_REQ6 J18 TRST P2 BPCCE U15 V

A16 V

F5 S_REQ2 J19 TCLK P3 P_GNT V5 P_AD28 B5 GND F6 S_AD30 K1 HSSWITCH/GPIO3 P5 P_AD30 V6 P_AD26 B6 S_AD27 F7 S_AD26 K2 GPIO2 P6 GND V7 P_IDSEL B7 V

F8 GND K3 V

P7 V

V8 V

B8 S_AD22 F9 S_AD20 K5 GPIO1 P8 P_AD24 V9 GND B9 S_AD19 F10 V

K6 GPIO0 P9 V

V10 P_AD16 B10 GND F11 S_FRAME K14 TMS P10 P_FRAME V11 P_IRDY B11 S_TRDY F12 S_C/BE1 K15 V

P11 P_DEVSEL V12 P_LOCK B12 S_STOP F13 GND K17 TDO P12 P_SERR V13 P_C/BE1 B13 S_SERR F14 S_AD9 K18 TDI P13 GND V14 P_AD13 B14 S_AD14 F15 S_AD10 K19 HSLED P14 GND V15 P_AD10 B15 S_AD12 F17 S_AD8 L1 S_CLKOUT0 P15 P_AD9 W4 V

C5 S_REQ0 F18 GND L2 S_CLKOUT1 P17 GND W5 P_AD27 C6 V

F19 S_AD7 L3 GND P18 P_AD7 W6 V

C7 S_AD25 G1 S_GNT3 L5 S_CLKOUT3 P19 V

W7 GND C8 S_AD23 G2 S_GNT2 L6 S_CLKOUT2 R1 P_REQ W8 P_AD21 C9 GND G3 GND L14 HSENUM R2 P_AD31 W9 P_AD20

C10 S_AD16 G5 S_REQ8 L15 MSK_IN R3 V

W10 P_AD17

C11 S_IRDY G6 S_REQ3 L17 NC R6 P_AD29 W11 V

C12 S_LOCK G14 S_AD6 L18 P_V

CCP

R7 P_AD25 W12 GND

C13 S_PAR G15 S_C/BE0 L19 GND R8 P_AD23 W13 V

C14 V

G17 V

M1 V

R9 P_AD18 W14 P_AD14

C15 GND G18 S_AD5 M2 S_CLKOUT4 R10 V

W15 P_AD11

D1 V

G19 S_AD4 M3 S_CLKOUT5 R11 P_STOP W16 GND

D19 GND H1 S_GNT7 M5 S_CLKOUT6 R12 P_PAR

E1 S_REQ5 H2 S_GNT6 M6 GND R13 V

E2 S_REQ4 H3 S_GNT5 M14 P_AD5 R14 NC E3 S_REQ1 H5 S_GNT4 M15 P_AD2 R17 MS1 E6 S_AD31 H6 S_GNT1 M17 V

R18 P_AD8 E7 S_AD28 H14 S_AD3 M18 P_AD1 R19 P_C/BE0 E8 S_C/BE3 H15 GND M19 P_AD0 T1 GND

2–7

T able 2–4. Primary PCI System

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

P_CLK 45 N5 I

Primary PCI bus clock. P_CLK provides timing for all transactions on the primary PCI bus. All primary PCI signals are sampled at rising edge of P_CLK.

P_RST

43 P1 I

PCI reset. When the primary PCI bus reset is asserted, P_RST causes the bridge to put all output buffers in a high–impedance state and reset all internal registers. When asserted, the device is completely nonfunctional. During P_RST

, the secondary interface is driven low. After P_RST is deasserted, the bridge

is in its default state.

Table 2–5. Primary PCI Address and Data

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

P_AD31 P_AD30 P_AD29 P_AD28 P_AD27 P_AD26 P_AD25 P_AD24 P_AD23 P_AD22 P_AD21 P_AD20 P_AD19 P_AD18 P_AD17 P_AD16 P_AD15 P_AD14 P_AD13 P_AD12 P_AD11 P_AD10

P_AD9 P_AD8 P_AD7 P_AD6 P_AD5 P_AD4 P_AD3 P_AD2 P_AD1 P_AD0

49 50 55 57 58 60 61 63 67 68 70 71 73 74 76 77 93 95 96 98

99 101 107 109 112 113 115 116 118 119 121 122

R2 P5 R6 V5 W5 V6 R7 P8 R8 U8 W8 W9 U9 R9

W10

V10 U13

W14

V14 U14

W15

V15 P15 R18 P18 N15 M14 N17 N19 M15 M18 M19

I/O

Primary address/data bus. These signals make up the multiplexed PCI address and data bus on the primary interface. During the address phase of a primary bus PCI cycle, P_AD31–P_AD0 contain a 32-bit address or other destination information. During the data phase, P_AD31–P_AD0 contain data.

P_C/BE3 P_C/BE2 P_C/BE1 P_C/BE0

92 110

U7 R10 V13 R19

I/O

Primary bus commands and byte enables. These signals are multiplexed on the same PCI terminals. During the address phase of a primary bus PCI cycle, P_C/BE3

–P_C/BE0 define the bus command. During the data phase, this 4-bit bus is used as byte enables. The byte enables determine which byte paths of the full 32-bit data bus carry meaningful data. P_C/BE0

applies to byte 0 (P_AD7–P_AD0),

P_C/BE1

applies to byte 1 (P_AD15–P_AD8), P_C/BE2 applies to byte 2 (P_AD23–P_AD16), and

P_C/BE3

applies to byte 3 (P_AD31–P_AD24).

2–8

Table 2–6. Primary PCI Interface Control

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

P_DEVSEL 84 P11 I/O

Primary device select. The bridge asserts P_DEVSEL to claim a PCI cycle as the target device. As a PCI initiator on the primary bus, the bridge monitors P_DEVSEL

until a target responds. If no target

responds before time-out occurs, then the bridge terminates the cycle with an initiator abort.

P_FRAME

80 P10 I/O

Primary cycle frame. P_FRAME is driven by the initiator of a primary bus cycle. P_FRAME is asserted to indicate that a bus transaction is beginning, and data transfers continue while this signal is asserted. When P_FRAME

is deasserted, the primary bus transaction is in the final data phase.

P_GNT

46 P3 I

Primary bus grant to bridge. P_GNT is driven by the primary PCI bus arbiter to grant the bridge access to the primary PCI bus after the current data transaction has completed. P_GNT

may or may not follow

a primary bus request, depending on the primary bus parking algorithm.

P_IDSEL 65 V7 I

Primary initialization device select. P_IDSEL selects the bridge during configuration space accesses. P_IDSEL can be connected to one of the upper 24 PCI address lines on the primary PCI bus.

Note: There is no IDSEL signal interfacing the secondary PCI bus; thus, the entire configuration space of the bridge can only be accessed from the primary bus.

P_IRDY 82 V11 I/O

Primary initiator ready. P_IRDY indicates ability of the primary bus initiator to complete the current data phase of the transaction. A data phase is completed on a rising edge of P_CLK where both P_IRDY and P_TRDY are asserted. Until P_IRDY and P_TRDY are both sampled asserted, wait states are inserted.

P_LOCK 87 V12 I/O Primary PCI bus lock. P_LOCK is used to lock the primary bus and gain exclusive access as an initiator.

P_PAR 90 R12 I/O

Primary parity. In all primary bus read and write cycles, the bridge calculates even parity across the P_AD and P_C/BE

buses. As an initiator during PCI write cycles, the bridge outputs this parity indicator with a one-P_CLK delay. As a target during PCI read cycles, the calculated parity is compared to the parity indicator of the initiator; a miscompare can result in a parity error assertion (P_PERR

P_PERR

88 U12 I/O

Primary parity error indicator. P_PERR is driven by a primary bus PCI device to indicate that calculated parity does not match P_PAR when P_PERR

is enabled through bit 6 of the command register.

P_REQ 47 R1 O

Primary PCI bus request. Asserted by the bridge to request access to the primary PCI bus as an initiator.

P_SERR 89 P12 O

Primary system error. Output pulsed from the bridge when enabled through the command register indicating a system error has occurred. The bridge needs not be the target of the primary PCI cycle to assert this signal. When bit 6 is enabled in the bridge control register (offset 3Eh, see Section 4.32), this signal also pulses indicating that a system error has occurred on one of the subordinate buses downstream from the bridge.

P_STOP 85 R11 I/O

Primary cycle stop signal. This signal is driven by a PCI target to request the initiator to stop the current primary bus transaction. This signal is used for target disconnects and is commonly asserted by target devices which do not support burst data transfers.

P_TRDY 83 U11 I/O

Primary target ready. P_TRDY indicates the ability of the primary bus target to complete the current data phase of the transaction. A data phase is completed upon a rising edge of P_CLK where both P_IRDY

and P_TRDY are asserted. Until both P_IRDY and P_TRDY are asserted, wait states are

inserted.

2–9

T able 2–7. Secondary PCI System

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

S_CLKOUT9 S_CLKOUT8 S_CLKOUT7 S_CLKOUT6 S_CLKOUT5 S_CLKOUT4 S_CLKOUT3 S_CLKOUT2 S_CLKOUT1 S_CLKOUT0

42 41 39 38 36 35 33 32 30 29

N6 N3 N1 M5 M3 M2

L5 L6 L2 L1

Secondary PCI bus clocks. Provide timing for all transactions on the secondary PCI bus. Each secondary bus device samples all secondary PCI signals at the rising edge of its corresponding S_CLKOUT input.

S_CLK

21 J3 I Secondary PCI bus clock input. This input syncronizes the PCI2050 to the secondary bus clocks.

S_CFN 23 J6 I

Secondary external arbiter enable. When this signal is high, the secondary external arbiter is enabled. When the external arbiter is enabled, the PCI2050 S_REQ0

pin is reconfigured as a secondary bus

grant input to the bridge and S_GNT0

is reconfigured as a secondary bus master request to the

external arbiter on the secondary bus.

S_RST 22 J5 O

Secondary PCI reset. S_RST is a logical OR of P_RST and the state of the secondary bus reset bit (bit 6) of the bridge control register (offset 3Eh, see Section 4.32). S_RST

is asynchronous with

respect to the state of the secondary interface CLK signal.

2–10

Table 2–8. Secondary PCI Address and Data

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

S_AD31 S_AD30 S_AD29 S_AD28 S_AD27 S_AD26 S_AD25 S_AD24 S_AD23 S_AD22 S_AD21 S_AD20 S_AD19 S_AD18 S_AD17 S_AD16 S_AD15 S_AD14 S_AD13 S_AD12 S_AD11 S_AD10

S_AD9 S_AD8 S_AD7 S_AD6 S_AD5 S_AD4 S_AD3 S_AD2 S_AD1 S_AD0

206 204 203 201 200 198 197 195 192 191 189 188 186 185 183 182 165 164 162 161 159 154 152 150 147 146 144 143 141 140 138 137

E6 F6 A5 E7 B6 F7 C7 A7 C8 B8 E9 F9 B9

A9 E10 C10 E13 B14 A15 B15 E14 F15 F14 F17 F19 G14 G18 G19 H14 H17 H19 J15

I/O

Secondary address/data bus. These signals make up the multiplexed PCI address and data bus on the secondary interface. During the address phase of a secondary bus PCI cycle, S_AD31–S_AD0 contain a 32-bit address or other destination information. During the data phase, S_AD31–S_AD0 contain data.

S_C/BE3 S_C/BE2 S_C/BE1 S_C/BE0

194 180 167 149

E8 A10 F12 G15

I/O

Secondary bus commands and byte enables. These signals are multiplexed on the same PCI terminals. During the address phase of a secondary bus PCI cycle, S_C/BE3

–S_C/BE0 define the bus command. During the data phase, this 4-bit bus is used as byte enables. The byte enables determine which byte paths of the full 32-bit data bus carry meaningful data. S_C/BE0

applies to byte 0

(S_AD7–S_AD0), S_C/BE1

applies to byte 1 (S_AD15–S_AD8), S_C/BE2 applies to byte 2

(S_AD23–S_AD16), and S_C/BE3

applies to byte 3 (S_AD31–S_AD24).

S_DEVSEL 175 A11 I/O

Secondary device select. The bridge asserts S_DEVSEL to claim a PCI cycle as the target device. As a PCI initiator on the secondary bus, the bridge monitors S_DEVSEL

until a target responds. If no target

responds before timeout occurs, then the bridge terminates the cycle with an initiator abort.

S_FRAME 179 F11 I/O

Secondary cycle frame. S_FRAME is driven by the initiator of a secondary bus cycle. S_FRAME is asserted to indicate that a bus transaction is beginning and data transfers continue while S_FRAME is asserted. When S_FRAME is deasserted, the secondary bus transaction is in the final data phase.

S_GNT8 S_GNT7 S_GNT6 S_GNT5 S_GNT4 S_GNT3 S_GNT2 S_GNT1 S_GNT0

19 18 17 16 15 14 13 11 10

J1 H1 H2 H3 H5 G1 G2 H6 F1

Secondary bus grant to the bridge. The bridge provides internal arbitration and these signals are used to grant potential secondary PCI bus masters access to the bus. T en potential initiators (including the bridge) can be located on the secondary PCI bus.

When the internal arbiter is disabled, S_GNT0

is reconfigured as an external secondary bus request

signal for the bridge.

2–11

Table 2–9. Secondary PCI Interface Control

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

S_IRDY 177 C11 I/O

Secondary initiator ready. S_IRDY indicates the ability of the secondary bus initiator to complete the current data phase of the transaction. A data phase is completed on a rising edge of S_PCLKn where both S_IRDY and S_TRDY are asserted; until S_IRDY and S_TRDY are asserted, wait states are inserted.

S_LOCK 172 C12 I/O

Secondary PCI bus lock. S_LOCK is used to lock the secondary bus and gain exclusive access as an initiator.

S_PAR 168 C13 I/O

Secondary parity. In all secondary bus read and write cycles, the bridge calculates even parity across the S_AD and S_C/BE

buses. As an initiator during PCI write cycles, the bridge outputs this parity indicator with a one-S_CLK delay . As a target during PCI read cycles, the calculated parity is compared to the initiator parity indicator. A miscompare can result in a parity error assertion (S_PERR

S_PERR

171 E12 I/O

Secondary parity error indicator. S_PERR is driven by a secondary bus PCI device to indicate that calculated parity does not match S_PAR when enabled through the command register.

S_REQ8 S_REQ7 S_REQ6 S_REQ5 S_REQ4 S_REQ3 S_REQ2 S_REQ1 S_REQ0

9 8 7 6 5 4 3 2

207

F2 F3 E1 E2

F5 E3 C5

Secondary PCI bus request signals. The bridge provides internal arbitration, and these signals are used as inputs from secondary PCI bus initiators requesting the bus. Ten potential initiators (including the bridge) can be located on the secondary PCI bus.

When the internal arbiter is disabled, the S_REQ0

signal is reconfigures as an external secondary bus

grant for the bridge.

S_SERR

169 B13 I

Secondary system error. S_SERR is passed through the primary interface by the bridge if enabled through the bridge control register. S_SERR

is never asserted by the bridge.

S_STOP 173 B12 I/O

Secondary cycle stop signal. S_STOP is driven by a PCI target to request the initiator to stop the current secondary bus transaction. S_STOP

is used for target disconnects and is commonly asserted by target

devices that do not support burst data transfers.

S_TRDY 176 B11 I/O

Secondary target ready. S_TRDY indicates the ability of the secondary bus target to complete the current data phase of the transaction. A data phase is completed on a rising edge of S_CLK where both S_IRDY

and S_TRDY are asserted; until S_IRDY and S_TRDY are asserted, wait states are inserted.

Table 2–10. Miscellaneous Terminals

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

BPCCE 44 P2 I

Bus/power clock control management terminal. When signal BPCCE is tied high, and when the PCI2050 is placed in the D3 power state, it enables the PCI2050 to place the secondary bus in the B2 power state. The PCI2050 disables the secondary clocks and drives them to 0. When tied low, placing the PCI2050 in the D3 power state has no ef fect on the secondary bus clocks.

GPIO3/HSSWITCH

GPIO2 GPIO1 GPIO0

24 25 27 28

K1 K2 K5 K6

General-purpose I/O pins GPIO3 is HSSWITCH

in CPCI mode.

HSSWITCH

provides the status of the ejector handle switch to the CPCI logic.

HSENUM 127 L14 O Hot swap ENUM

HSLED 128 K19 O Hot swap LED output

MS0

155 E17 I Mode select 0

MS1

106 R17 I Mode select 1

102 125

R14 L17

NC These terminals have no function on the PCI2050.

S_M66ENA 153 E18 O

Secondary bus 66-MHz enable pin. This pin is always driven low to incicate that the secondary bus speed is 33 MHz.

2–12

Table 2–11. JTAG Interface Terminals

TERMINAL

NAME

PDV

NO.

GHK

NO.

I/O DESCRIPTION

TCLK 133 J19 I JTAG boundary-scan clock. TCLK is the clock controlling the JTAG logic.

TDI 129 K18 I

JTAG serial data in. TDI is the serial input through which JTAG instructions and test data enter the JTAG interface. The new data on TDI is sampled on the rising edge of TCLK.

TDO 130 K17 O

JTAG serial data out. TDO is the serial output through which test instructions and data from the test logic leave the PCI2050.

TMS 132 K14 I JTAG test mode select. TMS causes state transitions in the test access port controller.

TRST 134 J18 I

JTAG TAP reset. When TRST is asserted low, the TAP controller is asynchronously forced to enter a reset state and initialize the test logic.

Table 2–12. Power Supply

TERMINAL

NAME PDV NO. GHK NO.

DESCRIPTION

GND

12, 20, 31, 37, 48, 52, 54,

59, 66, 72, 78, 86, 94, 100,

104, 111, 117, 123, 136, 142, 148, 156, 158, 160, 166, 174, 181, 187, 193,

199, 205

A6, A12, A14, B5, B10, C9,

C15, D19, F8, F13, F18,

G3, H15, J2, J14, L3, L19,

M6, N18, P6, P13, P14,

P17, T1, U5, U6, U10, V9,

W7, W12, W16

Device ground terminals

1, 26, 34, 40, 51, 53, 56, 62, 69, 75, 81, 91, 97, 103, 105,

108, 114, 120, 131, 139, 145, 151, 157, 163, 170, 178, 184, 190, 196, 202,

208

A4, A8, A13, A16, B7, C6,

C14, D1, E11, E19, F10,

G17, H18, K3, K15, M1, M17, N2, N14, P7, P9, P19, R3, R13, T19, U15, V8, W4,

W6, W11, W13

Power-supply terminal for core logic (3.3 V)

P_V

CCP

124 L18

Primary bus-signaling environment supply. P_V

CCP

is used in

protection circuitry on primary bus I/O signals.

S_V

CCP

135 J17

Secondary bus-signaling environment supply. S_V

CCP

is used in

protection circuitry on secondary bus I/O signals.

3–1

3 Feature/Protocol Descriptions

The following sections give an overview of the PCI2050 PCI-to-PCI bridge features and functionality. Figure 3–1 shows a simplified block diagram of a typical system implementation using the PCI2050.

PCI Option Card

CPU

Memory

Host

Bridge

PCI2050

PCI

Device

PCI

Device

PCI Bus 0

PCI Bus 1

Host Bus

PCI Option Slot

PCI2050

PCI

Device

PCI

Device

PCI Bus 2

(Option)

PCI Option Card

Figure 3–1. System Block Diagram

3.1 Introduction to the PCI2050

The PCI2050 is a bridge between two PCI buses and is compliant with both the

PCI Local Bus Specification

and the

PCI-to-PCI Bridge Specification

. The bridge supports two 32-bit PCI buses operating at a maximum of 33 MHz. The primary and secondary buses operate independently in either a 3.3-V or 5-V signaling environment. The core logic of the bridge, however, is powered at 3.3 V to reduce power consumption.

Host software interacts with the bridge through internal registers. These internal registers provide the standard PCI status and control for both the primary and secondary buses. Many vendor-specific features that exist in the TI extension register set are included in the bridge. The PCI configuration header of the bridge is only accessible from the primary PCI interface.

The bridge provides internal arbitration for the nine possible secondary bus masters, and provides each with a dedicated active low request/grant pair (REQ

/GNT). The arbiter features a two-tier rotational scheme with the

PCI2050 bridge defaulting to the highest priority tier. Upon system power up, power-on self-test (POST) software configures the bridge according to the devices that exist

on subordinate buses, and enables performance-enhancing features of the PCI2050. In a typical system, this is the only communication with the bridge internal register set.

3–2

3.2 PCI Commands

The bridge responds to PCI bus cycles as a PCI target device based on the decoding of each address phase and internal register settings. Table 3–1 lists the valid PCI bus cycles and their encoding on the command/byte enables (C/BE

) bus during the address phase of a bus cycle.

Table 3–1. PCI Command Definition

C/BE3–C/BE0

COMMAND

0000 Interrupt acknowledge 0001 Special cycle 0010 I/O read 0011 I/O write 0100 Reserved 0101 Reserved 0110 Memory read 0111 Memory write 1000 Reserved 1001 Reserved 1010 Configuration read 1011 Configuration write 1100 Memory read multiple 1101 Dual address cycle 1110 Memory read line

1111 Memory write and invalidate

The bridge never responds as a PCI target to the interrupt acknowledge, special cycle, or reserved commands. The bridge does, however, initiate special cycles on both interfaces when a type 1 configuration cycle issues the special cycle request. The remaining PCI commands address either memory , I/O, or configuration space. The bridge accepts PCI cycles by asserting DEVSEL

as a medium-speed device, i.e., DEVSEL is asserted two clock cycles after the

address phase. The PCI2050 converts memory write and invalidate commands to memory write commands when forwarding

transactions from either the primary or secondary side of the bridge if the bridge cannot guarantee that an entire cache line will be delivered.

3.3 Configuration Cycles

PCI Local Bus Specification

defines two types of PCI configuration read and write cycles: type 0 and type 1. The bridge decodes each type differently . T ype 0 configuration cycles are intended for devices on the primary bus, while type 1 configuration cycles are intended for devices on some hierarchically subordinate bus. The difference between these two types of cycles is the encoding of the primary PCI (P_AD) bus during the address phase of the cycle. Figure 3–2 shows the P_AD bus encoding during the address phase of a type 0 configuration cycle. The 6-bit register number field represents an 8-bit address with the two lower bits masked to 0, indicating a double-word boundary . This results in a 256-byte configuration address space per function per device. Individual byte accesses may be selected within a doubleword by using the P_C/BE

signals during the data phase of the cycle.

31 11 10 8 721 0

Reserved

Function

Number

0 0

Figure 3–2. PCI AD31–AD0 During Address Phase of a Type 0 Configuration Cycle

The bridge claims only type 0 configuration cycles when its P_IDSEL terminal is asserted during the address phase of the cycle and the PCI function number encoded in the cycle is 0. If the function number is 1 or greater, then the

3–3

bridge does not recognize the configuration command. In this case, the bridge does not assert DEVSEL, and the configuration transaction results in a master abort. The bridge services valid type 0 configuration read or write cycles by accessing internal registers from the configuration header (see Table 4–1).

Because type 1 configuration cycles are issued to devices on subordinate buses, the bridge claims type 1 cycles based on the bus number of the destination bus. The P_AD bus encoding during the address phase of a type 1 cycle is shown in Figure 3–3. The device number and bus number fields define the destination bus and device for the cycle.

31 24 23 16 15 1 1 10 8 721 0

Reserved Bus Number

Device

Number

Function

Number

0 1

Figure 3–3. PCI AD31–AD0 During Address Phase of a Type 1 Configuration Cycle

Several bridge configuration registers shown in Table 4–1 are significant when decoding and claiming type 1 configuration cycles. The destination bus number encoded on the P_AD bus is compared to the values programmed in the bridge configuration registers 18h, 19h, and 1Ah, which are the primary bus number, secondary bus number, and subordinate bus number registers, respectively. These registers default to 00h and are programmed by host software to reflect the bus hierarchy in the system (see Figure 3–4 for an example of a system bus hierarchy and how the PCI2050 bus number registers would be programmed in this case).

When the PCI2050 claims a type 1 configuration cycle that has a bus number equal to its secondary bus number, the PCI2050 converts the type 1 configuration cycle to a type 0 configuration cycle and asserts the proper S_AD line as the IDSEL (see Table 3–2). All other type 1 transactions that access a bus number greater than the bridge secondary bus number but less than or equal to its subordinate bus number are forwarded as type 1 configuration cycles.

T able 3–2. PCI S_AD31–S_AD16 During the Address

Phase of a Type 0 Configuration Cycle

DEVICE

NUMBER

SECONDARY IDSEL

S_AD31–S_AD16

S_AD

ASSERTED

0h 0000 0000 0000 0001 16 1h 0000 0000 0000 0010 17 2h 0000 0000 0000 0100 18 3h 0000 0000 0000 1000 19 4h 0000 0000 0001 0000 20 5h 0000 0000 0010 0000 21 6h 0000 0000 0100 0000 22 7h 0000 0000 1000 0000 23 8h 0000 0001 0000 0000 24 9h 0000 0010 0000 0000 25 Ah 0000 0100 0000 0000 26 Bh 0000 1000 0000 0000 27 Ch 0001 0000 0000 0000 28 Dh 0010 0000 0000 0000 29 Eh 0100 0000 0000 0000 30 Fh 1000 0000 0000 0000 31

10h–1Eh 0000 0000 0000 0000 –

3–4

PCI Bus 0

Primary Bus 00h Secondary Bus 01h Subordinate Bus 02h

PCI2050

Primary Bus 00h Secondary Bus 03h Subordinate Bus 03h

PCI2050

PCI Bus 1 PCI Bus 3

Primary Bus 01h Secondary Bus 02h Subordinate Bus 02h

PCI2050

PCI Bus 2

Figure 3–4. Bus Hierarchy and Numbering

3.4 Special Cycle Generation

The bridge is designed to generate special cycles on both buses through a type 1 cycle conversion. During a type 1 configuration cycle, if the bus number field matches the bridge secondary bus number, the device number field is 1Fh, and the function number field is 07h, then the bridge generates a special cycle on the secondary bus with a message that matches the type 1 configuration cycle data. If the bus number is a subordinate bus and not the secondary , then the bridge passes the type 1 special cycle request through to the secondary interface along with the proper message.

Special cycles are never passed through the bridge. Type 1 configuration cycles with a special cycle request can propagate in both directions.

3.5 Secondary Clocks

The PCI2050 provides 10 secondary clock outputs (S_CLKOUT[0:9]). Nine are provided for clocking secondary devices. The tenth clock should be routed back into the PCI2050 S_CLK input to ensure all secondary bus devices see the same clock.

3–5

PCI2050

PCI

Device

S_CLKOUT3

PCI

Device

PCI

Device

PCI

Device

S_CLKOUT2

S_CLKOUT1

S_CLKOUT0

S_CLKOUT9

S_CLK

Figure 3–5. Secondary Clock Block Diagram

3.6 Bus Arbitration

The PCI2050 implements bus request (P_REQ) and bus grant (P_GNT) terminals for primary PCI bus arbitration. Nine secondary bus requests and nine secondary bus grants are provided on the secondary of the PCI2050. Ten potential initiators, including the bridge, can be located on the secondary bus. The PCI2050 provides a two-tier arbitration scheme on the secondary bus for priority bus-master handling.

The two-tier arbitration scheme improves performance in systems in which master devices do not all require the same bandwidth. Any master that requires frequent use of the bus can be programmed to be in the higher priority tier.

3.6.1 Primary Bus Arbitration

The PCI2050, acting as an initiator on the primary bus, asserts P_REQ when forwarding transactions upstream to the primary bus. If a target disconnect, a target retry , or a target abort is received in response to a transaction initiated on the primary bus by the PCI2050, then the device deasserts P_REQ for two PCI clock cycles.

When the primary bus arbiter asserts P_GNT in response to a P_REQ from the PCI2050, the device initiates a transaction on the primary bus during the next PCI clock cycle after the primary bus is sampled idle.

When P_REQ

is not asserted and the primary bus arbiter asserts P_GNT to the PCI2050, the device responds by parking the P_AD31–P_AD0 bus, the C/BE3–C/BE0 bus, and primary parity (P_P AR) by driving them to valid logic levels. If the PCI2050 is parking the primary bus and wants to initiate a transaction on the bus, then it can start the transaction on the next PCI clock by asserting the primary cycle frame (P_FRAME

) while P_GNT is still asserted. If

P_GNT is deasserted, then the bridge must rearbitrate for the bus to initiate a transaction.

3.6.2 Internal Secondary Bus Arbitration

S_CFN controls the state of the secondary internal arbiter. The internal arbiter can be enabled by pulling S_CFN low or disabled by pulling S_CFN

high. The PCI2050 provides nine secondary bus request terminals and nine secondary

3–6

bus grant terminals. Including the bridge, there are a total of ten potential secondary bus masters. These request and grant signals are connected to the internal arbiter. When an external arbiter is implemented, S_REQ8–S_REQ1 and S_GNT8–S_GNT1 are placed in a high impedance mode.

3.6.3 External Secondary Bus Arbitration

An external secondary bus arbiter can be used instead of the PCI2050 internal bus arbiter. When using an external arbiter, the PCI2050 internal arbiter should be disabled by pulling S_CFN high.

When an external secondary bus arbiter is used, the PCI2050 internally reconfigures the S_REQ0

and S_GNT0 signals so that S_REQ0 becomes the secondary bus grant for the bridge and S_GNT0 becomes the secondary bus request for the bridge. This is done because S_REQ0 is an input and can thus be used to provide the grant input to the bridge, and S_GNT0 is an output and can thus provide the request output from the bridge.

When an external arbiter is used, all unused secondary bus grant outputs (S_GNT8

–S_GNT1) are placed in a high impedance mode. Any unused secondary bus request inputs (S_REQ8–S_REQ1) should be pulled high to prevent the inputs from oscillating.

3.7 Decode Options

The PCI2050 supports positive decoding on the primary interface and negative decoding on the secondary interface. Positive decoding is a method of address decoding in which a device responds only to accesses within an assigned address range. Negative decoding is a method of address decoding in which a device responds only to accesses outside of an assigned address range.

3.8 System Error Handling

The PCI2050 can be configured to signal a system error (SERR) for a variety of conditions. The P_SERR event disable register (offset 64h, see Section 5.4) and the P_SERR status register (offset 6Ah, see Section 5.9) provide control and status bits for each condition for which the bridge can signal SERR

. These individual bits enable SERR

reporting for both downstream and upstream transactions. By default, the PCI2050 will not signal SERR. If the PCI2050 is configured to signal SERR by setting bit 8 in the

command register (offset 04h, see Section 4.3), then the bridge signals SERR if any of the error conditions in the P_SERR event disable register occur and that condition is enabled. By default, all error conditions are enabled in the P_SERR event disable register . When the bridge signals SERR

, bit 14 in the secondary status register (offset 1Eh,

see Section 4.19) is set.

3.8.1 Posted Write Parity Error

If bit 1 in the P_SERR event disable register (offset 64h, see Section 5.4) is 0, then parity errors on the target bus during a posted write are passed to the initiating bus as a SERR. When this occurs, bit 1 of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3.8.2 Posted Write Timeout

If bit 2 in the P_SERR event disable register (offset 64h, see Section 5.4) is 0 and the retry timer expires while attempting to complete a posted write, then the PCI2050 signals SERR on the initiating bus. When this occurs, bit 2 of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3.8.3 Target Abort on Posted Writes

If bit 3 in the P_SERR event disable register (of fset 64h, see Section 5.4) is 0 and the bridge receives a target abort during a posted write transaction, then the PCI2050 signals SERR on the initiating bus. When this occurs, bit 3 of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3–7

3.8.4 Master Abort on Posted Writes

If bit 4 in the P_SERR event disable register (offset 64h, see Section 5.4) is 0 and a posted write transaction results in a master abort, then the PCI2050 signals SERR on the initiating bus. When this occurs, bit 4 of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3.8.5 Master Delayed Write Timeout

If bit 5 in the P_SERR event disable register (offset 64h, see Section 5.4) is 0 and the retry timer expires while attempting to complete a delayed write, then the PCI2050 signals SERR on the initiating bus. When this occurs, bit 5 of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3.8.6 Master Delayed Read Timeout

If bit 6 in the P_SERR event disable register (offset 64h, see Section 5.4) is 0 and the retry timer expires while attempting to complete a delayed read, then the PCI2050 signals SERR

on the initiating bus. When this occurs, bit 6

of the P_SERR status register (offset 6Ah, see Section 5.9) is set. The status bit is cleared by writing a 1.

3.8.7 Secondary SERR

The PCI2050 passes SERR from the secondary bus to the primary bus if it is enabled for SERR response (bit 8 in the command register (offset 04h, see Section 4.3) is 1) and bit 1 in the bridge control register (offset 3Eh, see Section 4.32) is set.

3.9 Parity Handling and Parity Error Reporting

When forwarding transactions, the PCI2050 attempts to pass the data parity condition from one interface to the other unchanged, whenever possible, to allow the master and target devices to handle the error condition.

3.9.1 Address Parity Error

If the parity error response bit (bit 6) in the command register (offset 04h, see Section 4.3) is set, then the PCI2050 signals SERR on address parity errors and target abort transactions.

3.9.2 Data Parity Error

If the parity error response bit (bit 6) in the command register (offset 04h, see Section 4.3) is set, then the PCI2050 signals PERR when it receives bad data. When the bridge detects bad parity , bit 15 (detected parity error) in the status register (offset 06h, see Section 4.4) is set.

If the bridge is configured to respond to parity errors via bit 6 in the command register (offset 04h, see Section 4.3), then bit 8 (data parity error detected) in the status register (offset 06h, see Section 4.4) is set when the bridge detects bad parity . The data parity error detected bit is also set when the bridge, as a bus master, asserts PERR or detects PERR

3.10 Master and Target Abort Handling

If the PCI2050 receives a target abort during a write burst, then it signals target abort back on the initiator bus. If it receives a target abort during a read burst, then it provides all of the valid data on the initiator bus and disconnects. T arget aborts for posted and nonposted transactions are reported as specified in the

PCI-to-PCI Bridge Specification

Master aborts for posted and nonposted transactions are reported as specified in the

PCI-to-PCI Bridge Specification

. If a transaction is attempted on the primary bus after a secondary reset is asserted, then the PCI2050 follows bit 5 (master abort mode) in the bridge control register (offset 3Eh, see Section 4.32) for reporting errors.

3.11 Discard Timer

The PCI2050 is free to discard the data or status of a delayed transaction that was completed with a delayed transaction termination when a bus master has not repeated the request within 2

or 215 PCI clocks (approximately

3–8

30 µs and 993 µs, respectively).

PCI Local Bus Specification

recommends that a bridge wait 215 PCI clocks before

discarding the transaction data or status. The PCI2050 implements a discard timer for use in delayed transactions. After a delayed transaction is completed

on the destination bus, the bridge may discard it under two conditions. The first condition occurs when a read transaction is made to a region of memory that is inside a defined prefetchable memory region, or when the command is a memory read line or a memory read multiple, implying that the memory region is prefetchable. The other condition occurs when the master originating the transaction (either a read or a write, prefetchable or nonprefetchable) has not retried the transaction within 210 or 215 clocks. The number of clocks is tracked by a timer referred to as the discard timer. When the discard timer expires, the bridge is required to discard the data. The PCI2050 default value for the discard timer is 2

clocks; however, this value can be set to 210 clocks by setting bit 9 in the bridge control register

(offset 3Eh, see Section 4.32). For more information on the discard timer, see

error conditions

PCI Local Bus

Specification

3.12 Delayed Transactions

The bridge supports delayed transactions as defined in

PCI Local Bus Specification

. A target must be able to complete the initial data phase in 16 PCI clocks or less from the assertion of the cycle frame (FRAME), and subsequent data phases must complete in eight PCI clocks or less. A delayed transaction consists of three phases:

• An initiator device issues a request.

• The target completes the request on the destination bus and signals the completion to the initiator.

• The initiator completes the request on the originating bus.

If the bridge is the target of a PCI transaction and it must access a slow device to write or read the requested data, and the transaction takes longer than 16 clocks, then the bridge must latch the address, the command, and the byte enables, and then issue a retry to the initiator. The initiator must end the transaction without any transfer of data and is required to retry the transaction later using the same address, command, and byte enables. This is the first phase of the delayed transaction.

During the second phase, if the transaction is a read cycle, the bridge fetches the requested data on the destination bus, stores it internally, and obtains the completion status, thus completing the transaction on the destination bus. If it is a write transaction, then the bridge writes the data and obtains the completion status, thus completing the transaction on the destination bus. The bridge stores the completion status until the master on the initiating bus retries the initial request.

During the third phase, the initiator rearbitrates for the bus. When the bridge sees the initiator retry the transaction, it compares the second request to the first request. If the address, command, and byte enables match the values latched in the first request, then the completion status (and data if the request was a read) is transferred to the initiator. At this point, the delayed transaction is complete. If the second request from the initiator does not match the first request exactly, then the bridge issues another retry to the initiator.

The PCI supports up to three delayed transactions in each direction at any given time.

3.13 Mode Selection

Table 3–3 shows the mode selection via MS0 (PDV terminal 155, GHK terminal E17) and MS1 (PDV terminal 106, GHK terminal R17).

3–9

Table 3–3. Configuration Via MS0 and MS1

MS0

MS1 MODE

0 0 Compact PCI hot-swap friendly

PCI Bus Power Management Interface Specification Revision 1.1

HSSWITCH/GPIO(3) functions as HSSWITCH

0 1 Compact PCI hot-swap disabled

PCI Bus Power Management Interface Specification Revision 1.1

HSSWITCH/GPIO(3) functions as GPIO(3)

1 X Intel compatible

No CPCI hot swap,

PCI Bus Power Management Interface Specification Revision 1.0

3.14 Compact PCI Hot-Swap Support

The PCI2050 is hot-swap friendly silicon that supports all of the hot-swap capable features, contains support for software control, and integrates circuitry required by the

CPCI Hot-Swap Specification

. T o be hot-swap capable, the

PCI2050 supports the following:

• Compliance with

PCI Local Bus Specification

• Tolerance of VCC from early power

• Asynchronous reset

• Tolerance of precharge voltage

• I/O buffers must meet modified V/I requirements

• Limited I/O pin voltage at precharge voltage

• Hot-swap control and status programming via extended PCI capabilities linked list

• Hot-swap terminals: HS_ENUM

, HS_SWITCH, and HS_LED

CPCI hot-swap defines a process for installing and removing PCI boards without adversely affecting a running system. The PCI2050 provides this functionality such that it can be implemented on a board that can be removed and inserted in a hot-swap system.

The PCI2050 provides three terminals to support hot-swap when configured to be in hot-swap mode: HS_ENUM (output), HS_SWITCH (input), and HS_LED (output). The HS_ENUM output indicates to the system that an insertion event occurred or that a removal event is about to occur. The HS_SWITCH input indicates the state of a board ejector handle, and the HS_LED output lights a blue LED to signal insertion and removal ready status.

3–10

3.15 JTAG Support

The PCI2050 implements a JT AG test port based on the IEEE Standard 1149.1,

IEEE Standard T est Access Port and

Boundary-Scan Architecture

. The JTAG test port consists of the following:

• A 5-wire test access port

• A test access port controller

• An instruction register

• A bypass register

• A boundary-scan register

3.15.1 Test Port Instructions

The PCI 2050 supports the following JTAG instructions:

• EXTEST, BYPASS, and SAMPLE

• HIGHZ and CLAMP

• Private (various private instructions used by TI for test purposes)

Table 3–4. JTAG Instructions and Op Codes

INSTRUCTION OP CODE DESCRIPTION

EXTEST 00000 External test: drives terminals from the boundary scan register SAMPLE 00001 Sample I/O terminals

CLAMP 00100 Drives terminals from the boundary scan register and selects the bypass register for shifts

HIGHZ 00101 Puts all outputs and I/O terminals except for the TDO terminal in a high–impedance state

BYPASS 11111 Selects the bypass register for shifts

Table 3–5. Boundary Scan Terminal Order

BOUNDARY SCAN

PDV TERMINAL

NUMBER

GHK TERMINAL

NUMBER

TERMINAL NAME

GROUP DISABLE

BOUNDARY-SCAN

CELL TYPE

0 137 J15 S_AD0 19 Bidirectional 1 138 H19 S_AD1 19 Bidirectional 2 140 H17 S_AD2 19 Bidirectional 3 141 H14 S_AD3 19 Bidirectional 4 143 G19 S_AD4 19 Bidirectional 5 144 G18 S_AD5 19 Bidirectional 6 146 G14 S_AD6 19 Bidirectional 7 147 F19 S_AD7 19 Bidirectional 8 149 G15 S_C/BE0 19 Bidirectional

9 150 F17 S_AD8 19 Bidirectional 10 152 F14 S_AD9 19 Bidirectional 11 153 E18 S_M66ENA 19 Bidirectional 12 154 F15 S_AD10 19 Bidirectional 13 155 E17 MS0 – Input 14 158 C15 S_AD11 19 Bidirectional 15 161 B15 S_AD12 19 Bidirectional 16 162 A15 S_AD13 19 Bidirectional 17 164 B14 S_AD14 19 Bidirectional 18 165 E13 S_AD15 19 Bidirectional 19 – – – – Control

3–11

Table 3–5. Boundary Scan Terminal Order (continued)

BOUNDARY SCAN

PDV TERMINAL

NUMBER

GHK TERMINAL

NUMBER

TERMINAL NAME

GROUP DISABLE

BOUNDARY-SCAN

CELL TYPE

20 167 F12 S_C/BE1 19 Bidirectional 21 168 C13 S_PAR 19 Bidirectional 22 169 B13 S_SERR – Input 23 171 E13 S_PERR 26 Bidirectional 24 172 C12 S_LOCK 26 Bidirectional 25 173 B12 S_STOP 26 Bidirectional 26 – – – – Control 27 175 A11 S_DEVSEL 26 Bidirectional 28 176 B11 S_TRDY 26 Bidirectional 29 177 C11 S_IRDY 26 Bidirectional 30 179 F11 S_FRAME 26 Bidirectional 31 180 A10 S_C/BE2 48 Bidirectional 32 182 C10 S_AD16 48 Bidirectional 33 183 E10 S_AD17 48 Bidirectional 34 185 A9 S_AD18 48 Bidirectional 35 186 B9 S_AD19 48 Bidirectional 36 188 F9 S_AD20 48 Bidirectional 37 189 E9 S_AD21 48 Bidirectional 38 191 B8 S_AD22 48 Bidirectional 39 192 C8 S_AD23 48 Bidirectional 40 194 E8 S_C/BE3 48 Bidirectional 41 195 A7 S_AD24 48 Bidirectional 42 197 C7 S_AD25 48 Bidirectional 43 198 F7 S_AD26 48 Bidirectional 44 200 B6 S_AD27 48 Bidirectional 45 201 E7 S_AD28 48 Bidirectional 46 203 A5 S_AD29 48 Bidirectional 47 204 F6 S_AD30 48 Bidirectional 48 – – – – Control 49 206 E6 S_AD31 48 Bidirectional 50 207 C5 S_REQ0 – Input 51 2 E3 S_REQ1 – Input 52 3 F5 S_REQ2 – Input 53 4 G6 S_REQ3 – Input 54 5 E2 S_REQ4 – Input 55 6 E1 S_REQ5 – Input 56 7 F3 S_REQ6 – Input 57 8 F2 S_REQ7 – Input 58 9 G5 S_REQ8 – Input

3–12

Table 3–5. Boundary Scan Terminal Order (continued)

BOUNDARY SCAN

PDV TERMINAL

NUMBER

GHK TERMINAL

NUMBER

TERMINAL NAME

GROUP DISABLE

BOUNDARY-SCAN

CELL TYPE

59 10 F1 S_GNT0 61 Output 60 11 H6 S_GNT1 61 Output 61 – – – – Control 62 13 G2 S_GNT2 61 Output 63 14 G1 S_GNT3 61 Output 64 15 H5 S_GNT4 61 Output 65 16 H3 S_GNT5 61 Output 66 17 H2 S_GNT6 61 Output 67 18 H1 S_GNT7 61 Output 68 19 J1 S_GNT8 61 Output 69 21 J3 S_CLK – Input 70 22 J5 S_RST 78 Output 71 23 J6 S_CFN – Input 72 24 K1 GPIO3 78 Bidirectional 73 25 K2 GPIO2 78 Bidirectional 74 27 K5 GPIO1 78 Bidirectional 75 28 K6 GPIO0 78 Bidirectional 76 29 L1 S_CLKOUT0 – Output 77 30 L2 S_CLKOUT1 – Output 78 – – – – Output 79 32 L6 S_CLKOUT2 – Output 80 33 L5 S_CLKOUT3 – Output 81 35 M2 S_CLKOUT4 – Output 82 36 M3 S_CLKOUT5 – Output 83 38 M5 S_CLKOUT6 – Output 84 39 N1 S_CLKOUT7 – Output 85 41 N3 S_CLKOUT8 – Output 86 42 N6 S_CLKOUT9 – Output 87 43 P1 P_RST – Input 88 44 P2 BPCCE – Input 89 45 N5 P_CLK – Input 90 46 P3 P_GNT – Input 91 47 R1 P_REQ 92 Output 92 – – – – Control 93 49 R2 P_AD31 111 Bidirectional 94 50 P5 P_AD30 111 Bidirectional 95 55 R6 P_AD29 111 Bidirectional 96 57 V5 P_AD28 111 Bidirectional 97 58 W5 P_AD27 111 Bidirectional

3–13

Table 3–5. Boundary Scan Terminal Order (continued)

BOUNDARY SCAN

PDV TERMINAL

NUMBER

GHK TERMINAL

NUMBER

TERMINAL NAME

GROUP DISABLE

BOUNDARY-SCAN

CELL TYPE

98 60 V6 P_AD26 111 Bidirectional

99 61 R7 P_AD25 111 Bidirectional 100 63 W6 P_AD24 111 Bidirectional 101 64 U7 P_C/BE3 111 Bidirectional 102 65 V7 P_IDSEL – Input 103 67 R8 P_AD23 111 Bidirectional 104 68 U8 P_AD22 111 Bidirectional 105 70 W8 P_AD21 111 Bidirectional 106 71 W9 P_AD20 111 Bidirectional 107 73 U9 P_AD19 111 Bidirectional 108 74 R9 P_AD18 111 Bidirectional 109 76 W10 P_AD17 111 Bidirectional 110 77 V10 P_AD16 111 Bidirectional

111 – – – – Control 112 79 R10 P_C/BE2 111 Bidirectional 113 80 P10 P_FRAME 118 Bidirectional 114 82 V11 P_IRDY 118 Bidirectional 115 83 U11 P_TRDY 118 Bidirectional 116 84 P11 P_DEVSEL 118 Bidirectional 117 85 R11 P_STOP 118 Bidirectional 118 – – – – Control 119 87 V12 P_LOCK 118 Input 120 88 U12 P_PERR 118 Bidirectional 121 89 P12 P_SERR 142 Output 122 90 R12 P_PAR 142 Bidirectional 123 92 V13 P_C/BE1 142 Bidirectional 124 93 U13 P_AD15 142 Bidirectional 125 95 W14 P_AD14 142 Bidirectional 126 96 V14 P_AD13 142 Bidirectional 127 98 U14 P_AD12 142 Bidirectional 128 99 W15 P_AD11 142 Bidirectional 129 101 V15 P_AD10 142 Bidirectional 130 106 R17 MS1 – Input 131 107 P15 P_AD9 142 Bidirectional 132 109 R18 P_AD8 142 Bidirectional 133 110 R19 P_C/BE0 142 Bidirectional 134 112 P18 P_AD7 142 Bidirectional 135 113 N15 P_AD6 142 Bidirectional 136 115 M14 P_AD5 142 Bidirectional 137 116 N17 P_AD4 142 Bidirectional 138 118 N19 P_AD3 142 Bidirectional

3–14

Table 3–5. Boundary Scan Terminal Order (continued)

BOUNDARY SCAN

PDV TERMINAL

NUMBER

GHK TERMINAL

NUMBER

TERMINAL NAME

GROUP DISABLE

BOUNDARY-SCAN

CELL TYPE

139 119 M15 P_AD2 142 Bidirectional 140 121 M18 P_AD1 142 Bidirectional 141 122 M19 P_AD0 142 Bidirectional 142 – – – – – 143 126 L15 MSK_IN – Input 144 – – – – Control 145 127 L14 HS_ENUM 144 Output 146 128 K19 HS_LED 144 Output

3.16 GPIO Interface

The PCI2050 implements a four-terminal general-purpose I/O interface. Besides functioning as a general-purpose I/O interface, the GPIO terminals can be used to read in the secondary clock mask and to stop the bridge from accepting I/O and memory transactions.

3.16.1 Secondary Clock Mask

The PCI2050 uses GPIO0, GPIO2, and MSK_IN to shift in the secondary clock mask from an external shift register.

Bit 15

MSK_IN

Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

GPIO2

GPIO0

P_RST

S_RST

Figure 3–6. Clock Mask Read Timing After Reset

Table 3–6. Clock Mask Data Format

BIT CLOCK

[0:1] S_CLKOUT0 [2:3] S_CLKOUT1 [4:5] S_CLKOUT2 [6:7] S_CLKOUT3

8 S_CLKOUT4

9 S_CLKOUT5 10 S_CLKOUT6 11 S_CLKOUT7 12 S_CLKOUT8 13 S_CLKOUT9 (PCI2050 S_CLK input)

[14:15] Reserved

3–15

3.16.2 Transaction Forwarding Control

The PCI 2050 will stop forwarding I/O and memory transactions if bit 5 of the chip control register (offset 40h, see Section 5.1) is set to 1 and GPIO3 is driven high. The bridge will complete all queued posted writes and delayed requests, but delayed completions will not be returned until GPIO3 is driven low and transaction forwarding is resumed. The bridge will continue to accept configuration cycles in this mode. This feature is not available when in compact PCI hot-swap mode because GPIO3 iis used as the HS_SWITCH

input in this mode.

3.17 PCI Power Management

The

PCI Power Management Specification

establishes the infrastructure required to let the operating system control the power of PCI functions. This is done by defining a standard PCI interface and operations to manage the power of PCI functions on the bus. The PCI bus and the PCI functions can be assigned one of four software visible power management states, which result in varying levels of power savings.

The four power management states of PCI functions are D0 — fully on state, D1 and D2 — intermediate states, and D3 — off state. Similarly , bus power states of the PCI bus are B0–B3. The bus power states B0–B3 are derived from the device power state of the originating PCI2050 device.

For the operating system to manage the device power states on the PCI bus, the PCI function supports four power management operations:

• Capabilities reporting

• Power status reporting

• Setting the power state

• System wake-up

The operating system identifies the capabilities of the PCI function by traversing the new capabilities list. The presence of the new capabilities list is indicated by a bit in the status register (offset 06h, see Section 4.4) which provides access to the capabilities list.

3.17.1 Behavior in Low Power States

The PCI2050 supports D0, D1, D2, and D3

hot

power states when in TI mode. The PCI2050 only supports D0 and D3 power states when in Intel mode. The PCI2050 is fully functional only in D0 state. In the lower power states, the bridge does not accept any memory or I/O transactions. These transactions are aborted by the master. The bridge accepts type 0 configuration cycles in all power states except D3

cold

. The bridge also accepts type 1 configuration cycles but does not pass these cycles to the secondary bus in any of the lower power states. Type 1 configuration writes are discarded and reads return all 1s. All error reporting is done in the low power states. When in D2 and D3

hot

states, the bridge turns off all secondary clocks for further power savings. When going from D3

hot

to D0, an internal reset is generated. This reset initializes all PCI configuration registers to

their default values. All TI specific registers (40h – FFh) are not reset. Power management registers are also not reset.

3–16

4–1

4 Bridge Configuration Header

The PCI2050 bridge is a single-function PCI device. The configuration header is in compliance with the

PCI-to-PCI

Bridge Architecture Specification 1.0

. Table 4–1 shows the PCI configuration header, which includes the predefined portion of the bridge’s configuration space. The PCI configuration offset is shown in the right column under the OFFSET heading.

Table 4–1. Bridge Configuration Header

Device ID Vendor ID 00h

Status Command 04h

Class code Revision ID 08h

BIST Header type Primary latency timer Cache line size 0Ch

Base address 0 10h Base address 1 14h

Secondary bus latency timer Subordinate bus number Secondary bus number Primary bus number 18h

Secondary status I/O limit I/O base 1Ch

Memory limit Memory base 20h

Prefetchable memory limit Prefetchable memory base 24h

Prefetchable base upper 32 bits 28h

Prefetchable limit upper 32 bits 2Ch

I/O limit upper 16 bits I/O base upper 16 bits 30h

Reserved Capability pointer 34h

Expansion ROM base address 38h Bridge control Interrupt pin Interrupt line 3Ch Arbiter control Extended diagnostic Chip control 40h

Reserved 44h Reserved 48h Reserved 4Ch Reserved 50h Reserved 54h Reserved 58h

Reserved Reserved 5Ch

Reserved Reserved Reserved Reserved 60h

GPIO input data GPIO output enable GPIO output data P_SERR event disable 64h

Reserved P_SERR status Secondary clock control 68h

Reserved 6Ch–D8h

Power management capabilities PM next item pointer PM capability ID DCh

Data PMCSR bridge support Power management control/status E0h

Reserved Hot swap control status HS next item pointer HS capability ID E4h

Reserved E8h–FFh

4–2

4.1 Vendor ID Register

This 16-bit value is allocated by the PCI Special Interest Group (SIG) and identifies TI as the manufacturer of this device. The vendor ID assigned to TI is 104Ch.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Vendor ID Type R R R R R R R R R R R R R R R R Default 0 0 0 1 0 0 0 0 0 1 0 0 1 1 0 0

4.2 Device ID Register

This 16-bit value is allocated by the vendor and identifies the PCI device. The device ID for the PCI2050 is AC23h.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Device ID Type R R R R R R R R R R R R R R R R Default 1 0 1 0 1 1 0 0 0 0 1 0 0 0 1 1

4–3

4.3 Command Register

The command register provides control over the bridge interface to the primary PCI bus. VGA palette snooping is enabled through this register, and all other bits adhere to the definitions in the

PCI Local Bus Specification

. Table 4–2

describes the bit functions in the command register.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Command Type R R R R R R R/W R/W R R/W R/W R R R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 4–2. Command Register

BIT TYPE FUNCTION

15–10 R Reserved

9 R/W

Fast back-to-back enable. The bridge does not generate fast back-to-back transactions on the primary PCI bus. Bit 9 is read/write, but does not affect the bridge when set. This bit defaults to 0.

8 R/W

System error (SERR) enable. Bit 8 controls the enable for the SERR driver on the primary interface.

0 = Disable SERR

driver on primary interface (default)

1 = Enable the SERR

driver on primary interface

7 R

Wait cycle control. Bit 7 controls address/data stepping by the bridge on both interfaces. The bridge does not support address/data stepping and this bit is hardwired to 0.

6 R/W

Parity error response enable. Bit 6 controls the bridge response to parity errors.

0 = Parity error response disabled (default) 1 = Parity error response enabled

5 R/W

VGA palette snoop enable. When set, the bridge passes I/O writes on the primary PCI bus with addresses 3C6h, 3C8h, and 3C9h inclusive of ISA aliases (i.e., only bits AD9–AD0 are included in the decode).

4 R Memory write and invalidate enable. In a PCI-to-PCI bridge, bit 4 must be read-only and return 0 when read. 3 R

Special cycle enable. A PCI-to-PCI bridge cannot respond as a target to special cycle transactions, so bit 3 is defined as read-only and must return 0 when read.

2 R/W

Bus master enable. Bit 2 controls the ability of the bridge to initiate a cycle on the primary PCI bus. When bit 2 is 0, the bridge does not respond to any memory or I/O transactions on the secondary interface since they cannot be forwarded to the primary PCI bus.

0 = Bus master capability disabled (default) 1 = Bus master capability enabled

1 R/W

Memory space enable. Bit 1 controls the bridge response to memory accesses for both prefetchable and nonprefetchable memory spaces on the primary PCI bus. Only when bit 1 is set will the bridge forward memory accesses to the secondary bus from a primary bus initiator.

0 = Memory space disabled (default) 1 = Memory space enabled

0 R/W

I/O space enable. Bit 0 controls the bridge response to I/O accesses on the primary interface. Only when bit 0 is set will the bridge forward I/O accesses to the secondary bus from a primary bus initiator.

0 = I/O space disabled (default) 1 = I/O space enabled

4–4

4.4 Status Register

The status register provides device information to the host system. Bits in this register are cleared by writing a 1 to the respective bit; writing a 0 to a bit location has no effect. Table 4–3 describes the status register.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Status Type R/W R/W R/W R/W R/W R R R/W R R R R R R R R Default 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0

Table 4–3. Status Register

BIT TYPE FUNCTION

15 R/W Detected parity error. Bit 15 is set when a parity error is detected.

14 R/W

Signaled system error (SERR). Bit 14 is set if SERR is enabled in the command register (offset 04h, see Section 4.3) and the bridge signals a system error (SERR). See Section 3.8, System Error Handling.

0 = No SERR signaled (default) 1 = Signals SERR

13 R/W

Received master abort. Bit 13 is set when a cycle initiated by the bridge on the primary bus has been terminated by a master abort.

0 = No master abort received (default) 1 = Master abort received

12 R/W

Received target abort. Bit 12 is set when a cycle initiated by the bridge on the primary bus has been terminated by a target abort.

0 = No target abort received (default) 1 = Target abort received

11 R/W

Signaled target abort. Bit 11 is set by the bridge when it terminates a transaction on the primary bus with a target abort.

0 = No target abort signaled by the bridge (default) 1 = T arget abort signaled by the bridge

10–9 R

DEVSEL timing. These read-only bits encode the timing of P_DEVSEL and are hardwired 01b, indicating that the bridge asserts this signal at a medium speed.

8 R/W

Data parity error detected. Bit 8 is encoded as:

0 = The conditions for setting this bit have not been met. No parity error detected. (default) 1 = A data parity error occurred and the following conditions were met:

a. P_PERR

was asserted by any PCI device including the bridge. b. The bridge was the bus master during the data parity error. c. The parity error response bit (bit 6) is set in the command register (offset 04h, see Section 4.3).

7 R

Fast back-to-back capable. The bridge does not support fast back-to-back transactions as a target; therefore, bit 7 is hardwired to 0.

6 R

User-definable feature (UDF) support. The PCI2050 does not support the user-definable features; therefore, bit 6 is hardwired to 0.

5 R 66-MHz capable. The PCI2050 operates at a maximum P_CLK frequency of 33 MHz; therefore, bit 5 is hardwired to 0. 4 R

Capabilities list. Bit 4 is read-only and is hardwired to 1, indicating that capabilities additional to standard PCI are implemented. The linked list of PCI power management capabilities is implemented by this function.

3–0 R Reserved. Bits 3–0 return 0s when read.

4–5

4.5 Revision ID Register

The revision ID register indicates the silicon revision of the PCI2050.

Bit 7 6 5 4 3 2 1 0 Name Revision ID Type R R R R R R R R Default 0 0 0 0 0 0 0 0

4.6 Class Code Register

This register categorizes the PCI2050 as a PCI-to-PCI bridge device (0604h) with a 00h programming interface.

Bit 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Class code

Base class Sub class Programming interface

Type R R R R R R R R R R R R R R R R R R R R R R R R Default 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

4.7 Cache Line Size Register

The cache line size register is programmed by host software to indicate the system cache line size needed by the bridge on memory read line and memory read multiple transactions.

Bit 7 6 5 4 3 2 1 0 Name Cache line size Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4–6

4.8 Primary Latency Timer Register

The latency timer register specifies the latency timer for the bridge in units of PCI clock cycles. When the bridge is a primary PCI bus initiator and asserts P_FRAME, the latency timer begins counting from 0. If the latency timer expires before the bridge transaction has terminated, then the bridge terminates the transaction when its P_GNT is deasserted.

Bit 7 6 5 4 3 2 1 0 Name Latency timer Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4.9 Header Type Register

The header type register is read-only and returns 01h when read, indicating that the PCI2050 configuration space adheres to the PCI-to-PCI bridge configuration. Only the layout for bytes 10h–3Fh of configuration space is considered.

Bit 7 6 5 4 3 2 1 0 Name Header type Type R R R R R R R R Default 0 0 0 0 0 0 0 1

4.10 BIST Register

The PCI2050 does not support built-in self test (BIST). The BIST register is read-only and returns the value 00h when read.

Bit 7 6 5 4 3 2 1 0 Name BIST Type R R R R R R R R Default 0 0 0 0 0 0 0 0

4–7

4.11 Base Address Register 0

The bridge requires no additional resources. Base address register 0 is read-only and returns 0s when read.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Name Base address register 0 Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Base address register 0 Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.12 Base Address Register 1

The bridge requires no additional resources. Base address register 1 is read-only and returns 0s when read.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Name Base address register 1 Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Base address register 1 Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.13 Primary Bus Number Register

The primary bus number register indicates the primary bus number to which the bridge is connected. The bridge uses this register, in conjunction with the secondary bus number and subordinate bus number registers, to determine when to forward PCI configuration cycles to the secondary buses.

Bit 7 6 5 4 3 2 1 0 Name Primary bus number Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4–8

4.14 Secondary Bus Number Register

The secondary bus number register indicates the secondary bus number to which the bridge is connected. The PCI2050 uses this register, in conjunction with the primary bus number and subordinate bus number registers, to determine when to forward PCI configuration cycles to the secondary buses. Configuration cycles directed to the secondary bus are converted to type 0 configuration cycles.

Bit 7 6 5 4 3 2 1 0 Name Secondary bus number Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4.15 Subordinate Bus Number Register

The subordinate bus number register indicates the bus number of the highest numbered bus beyond the primary bus existing behind the bridge. The PCI2050 uses this register, in conjunction with the primary bus number and secondary bus number registers, to determine when to forward PCI configuration cycles to the subordinate buses. Configuration cycles directed to a subordinate bus (not the secondary bus) remain type 1 cycles as the cycle crosses the bridge.

Bit 7 6 5 4 3 2 1 0 Name Subordinate bus number Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4.16 Secondary Bus Latency Timer Register

The secondary bus latency timer specifies the latency timer for the bridge in units of PCI clock cycles. When the bridge is a secondary PCI bus initiator and asserts S_FRAME, the latency timer begins counting from 0. If the latency timer expires before the bridge transaction has terminated, then the bridge terminates the transaction when its S_GNT is deasserted. The PCI-to-PCI bridge S_GNT is an internal signal and is removed when another secondary bus master arbitrates for the bus.

Bit 7 6 5 4 3 2 1 0 Name Secondary bus latency timer Type R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0

4–9

4.17 I/O Base Register

The I/O base register is used in decoding I/O addresses to pass through the bridge. The bridge supports 32-bit I/O addressing; thus, bits 3–0 are read-only and default to 0001b. The upper four bits are writable and correspond to address bits AD15–AD12. The lower 12 address bits of the I/O base address are considered 0. Thus, the bottom of the defined I/O address range is aligned on a 4K-byte boundary. The upper 16 address bits of the 32-bit I/O base address corresponds to the contents of the I/O base upper 16 bits register (offset 30h, see Section 4.26).

Bit 7 6 5 4 3 2 1 0 Name I/O base Type R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 1

4.18 I/O Limit Register

The I/O limit register is used in decoding I/O addresses to pass through the bridge. The bridge supports 32-bit I/O addressing; thus, bits 3–0 are read-only and default to 0001b. The upper four bits are writable and correspond to address bits AD15–AD12. The lower 12 address bits of the I/O limit address are considered FFFh. Thus, the top of the defined I/O address range is aligned on a 4K-byte boundary. The upper 16 address bits of the 32-bit I/O limit address corresponds to the contents of the I/O limit upper 16 bits register (offset 32h, see Section 4.27).

Bit 7 6 5 4 3 2 1 0 Name I/O limit Type R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 1

4–10

4.19 Secondary Status Register

The secondary status register is similar in function to the status register (offset 06h, see Section 4.4); however, its bits reflect status conditions of the secondary interface. Bits in this register are cleared by writing a 1 to the respective bit.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Secondary status Type R/W R/W R/W R/W R/W R R R/W R R R R R R R R Default 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Table 4–4. Secondary Status Register

BIT TYPE FUNCTION

15 R/W

Detected parity error. Bit 15 is set when a parity error is detected on the secondary interface.

0 = No parity error detected on the secondary bus (default) 1 = Parity error detected on the secondary bus

14 R/W

Received system error. Bit 14 is set when the secondary interface detects S_SERR asserted. Note that the bridge never asserts S_SERR

0 = No S_SERR

detected on the secondary bus (default)

1 = S_SERR

detected on the secondary bus

13 R/W

Received master abort. Bit 13 is set when a cycle initiated by the bridge on the secondary bus has been terminated by a master abort.

0 = No master abort received (default) 1 = Bridge master aborted the cycle

12 R/W

Received target abort. Bit 12 is set when a cycle initiated by the bridge on the secondary bus has been terminated by a target abort.

0 = No target abort received (default) 1 = Bridge received a target abort

11 R/W

Signaled target abort. Bit 1 1 is set by the bridge when it terminates a transaction on the secondary bus with a target abort.

0 = No target abort signaled (default) 1 = Bridge signaled a target abort

10–9 R

DEVSEL timing. These read-only bits encode the timing of S_DEVSEL and are hardwired to 01b, indicating that the bridge asserts this signal at a medium speed.

8 R/W

Data parity error detected.

0 = The conditions for setting this bit have not been met 1 = A data parity error occurred and the following conditions were met:

a. S_PERR

was asserted by any PCI device including the bridge. b. The bridge was the bus master during the data parity error. c. The parity error response bit (bit 1) is set in the bridge control register (offset 3Eh, see Section 4.32).

7 R Fast back-to-back capable. Bit 7 is hardwired to 0. 6 R User-definable feature (UDF) support. Bit 6 is hardwired to 0. 5 R 66 MHz capable. Bit 5 is hardwired to 0.

4–0 R Reserved. Bits 4–0 return 0s when read.

4–11

4.20 Memory Base Register

The memory base register defines the base address of a memory-mapped I/O address range used by the bridge to determine when to forward memory transactions from one interface to the other. The upper 12 bits of this register are read/write and correspond to the address bits AD31–AD20. The lower 20 address bits are considered 0s; thus, the address range is aligned to a 1M-byte boundary. The bottom four bits are read-only and return 0s when read.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Memory base Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.21 Memory Limit Register

The memory limit register defines the upper-limit address of a memory-mapped I/O address range used to determine when to forward memory transactions from one interface to the other. The upper 12 bits of this register are read/write and correspond to the address bits AD31–AD20. The lower 20 address bits are considered 1s; thus, the address range is aligned to a 1M-byte boundary. The bottom four bits are read-only and return 0s when read.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Memory limit Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.22 Prefetchable Memory Base Register

The prefetchable memory base register defines the base address of a prefetchable memory address range used by the bridge to determine when to forward memory transactions from one interface to the other. The upper 12 bits of this register are read/write and correspond to the address bits AD31–AD20. The lower 20 address bits are considered 0; thus, the address range is aligned to a 1M-byte boundary. The bottom four bits are read-only and return 0s when read.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Prefetchable memory base Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4–12

4.23 Prefetchable Memory Limit Register

The prefetchable memory limit register defines the upper-limit address of a prefetchable memory address range used to determine when to forward memory transactions from one interface to the other. The upper 12 bits of this register are read/write and correspond to the address bits AD31–AD20. The lower 20 address bits are considered 1s; thus, the address range is aligned to a 1M-byte boundary. The bottom four bits are read-only and return 0s when read.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Prefetchable memory limit Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.24 Prefetchable Base Upper 32 Bits Register

The prefetchable base upper 32 bits register plus the prefetchable memory base register defines the base address of the 64-bit prefetchable memory address range used by the bridge to determine when to forward memory transactions from one interface to the other. The prefetchable base upper 32 bits register should be programmed to all zeros when 32-bit addressing is being used.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Name Prefetchable base upper 32 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Prefetchable base upper 32 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4–13

4.25 Prefetchable Limit Upper 32 Bits Register

The prefetchable LIMIT upper 32 bits register plus the prefetchable memory LIMIT register defines the base address of the 64-bit prefetchable memory address range used by the bridge to determine when to forward memory transactions from one interface to the other. The prefetchable LIMIT upper 32 bits register should be programmed to all zeros when 32-bit addressing is being used.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Name Prefetchable limit upper 32 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Prefetchable limit upper 32 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.26 I/O Base Upper 16 Bits Register

The I/O base upper 16 bits register specifies the upper 16 bits corresponding to AD31–AD16 of the 32-bit address that specifies the base of the I/O range to forward from the primary PCI bus to the secondary PCI bus.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name I/O base upper 16 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.27 I/O Limit Upper 16 Bits Register

The I/O limit upper 16-bits register specifies the upper 16 bits corresponding to AD31–AD16 of the 32-bit address that specifies the upper limit of the I/O range to forward from the primary PCI bus to the secondary PCI bus.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name I/O limit upper 16 bits Type R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4–14

4.28 Capability Pointer Register

The capability pointer register provides the pointer to the PCI configuration header where the PCI power management register block resides. The capability pointer provides access to the first item in the linked list of capabilities. The capability pointer register is read-only and returns DCh when read, indicating the power management registers are located at PCI header offset DCh.

Bit 7 6 5 4 3 2 1 0 Name Capability pointer register Type R R R R R R R R Default 1 1 0 1 1 1 0 0

4.29 Expansion ROM Base Address Register

The PCI2050 does not implement the expansion ROM remapping feature. The expansion ROM base address register returns all 0s when read.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 Name Expansion ROM base address Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Expansion ROM base address Type R R R R R R R R R R R R R R R R Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

4.30 Interrupt Line Register

The interrupt line register is read/write and is used to communicate interrupt line routing information. Since the bridge does not implement an interrupt signal terminal, this register defaults to FFh.

Bit 7 6 5 4 3 2 1 0 Name Interrupt line Type R/W R/W R/W R/W R/W R/W R/W R/W Default 1 1 1 1 1 1 1 1

4–15

4.31 Interrupt Pin Register

The bridge default state does not implement any interrupt terminals. Reads from bits 7–0 of this register return 0s.

Bit 7 6 5 4 3 2 1 0 Name Interrupt pin Type R R R R R R R R Default 0 0 0 0 0 0 0 0

4.32 Bridge Control Register

The bridge control register provides many of the same controls for the secondary interface that are provided by the command register for the primary interface. Some bits affect the operation of both interfaces.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Bridge control Type R R R R R/W R/W R/W R/W R R/W R/W R R/W R/W R/W R/W Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Table 4–5. Bridge Control Register

BIT TYPE FUNCTION

15–12 R Reserved. Bits 15–12 return 0s when read.

11 R/W

Discard timer SERR enable.

0 = SERR

signaling disabled for primary discard timeouts (default)

1 = SERR

signaling enabled for primary discard timeouts

10 R/W

Discard timer status. Once set, this bit must be cleared by writing 1 to this bit.

0 = No discard timer error (default) 1 = Discard timer error. Either primary or secondary discard timer expired and a delayed transaction was discarded from

the queue in the bridge.

9 R/W

Secondary discard timer. Selects the number of PCI clocks that the bridge will wait for a master on the secondary interface to repeat a delayed transaction request.

0 = Secondary discard timer counts 215 PCI clock cycles (default) 1 = Secondary discard timer counts 210 PCI clock cycles

8 R/W

Primary discard timer. Selects the number of PCI clocks that the bridge will wait for a master on the primary interface to repeat a delayed transaction request.

0 = the primary discard timer counts 215 PCI clock cycles (default) 1 = the primary discard timer counts 210 PCI clock cycles

7 R

Fast back-to-back capable. The bridge never generates fast back-to-back transactions to different secondary devices. Bit 7 returns 0 when read.

6 R/W

Secondary bus reset. When bit 6 is set, the secondary reset signal (S_RST) is asserted. S_RST is deasserted by resetting this bit. Bit 6 is encoded as:

0 = Do not force the assertion of S_RST

(default).

1 = Force the assertion of S_RST

4–16

Table 4–5. Bridge Control Register (continued)

BIT TYPE FUNCTION

5 R/W

Master abort mode. Bit 5 controls how the bridge responds to a master abort that occurs on either interface when the bridge is the master. If this bit is set, the posted write transaction has completed on the requesting interface, and SERR

enable

(bit 8) of the command register (offset 04h, see Section 4.3) is 1, then P_SERR

is asserted when a master abort occurs. If the transaction has not completed, then a target abort is signaled. If the bit is cleared, then all 1s are returned on reads and write data is accepted and discarded when a transaction that crosses the bridge is terminated with master abort. The default state of bit 5 after a reset is 0.

0 = Do not report master aborts (return FFFF FFFFh on reads and discard data on writes) (default). 1 = Report master aborts by signaling target abort if possible, or if SERR

is enabled via bit 1 of this register, by

asserting SERR

4 R Reserved. Returns 0 when read. Writes have no effect.

3 R/W

VGA enable. When bit 3 is set, the bridge positively decodes and forwards VGA-compatible memory addresses in the video frame buffer range 000A 0000h–000B FFFFh, I/O addresses in the range 03B0h–03BBh, and 03C0–03DFh from the primary to the secondary interface, independent of the I/O and memory address ranges. When this bit is set, the bridge blocks forwarding of these addresses from the secondary to the primary. Reset clears this bit. Bit 3 is encoded as:

0 = Do not forward VGA-compatible memory and I/O addresses from the primary to the secondary interface

(default).

1 = Forward VGA-compatible memory and I/O addresses from the primary to the secondary, independent of the I/O

and memory address ranges and independent of the ISA enable bit.

2 R/W

ISA enable. When bit 2 is set, the bridge blocks the forwarding of ISA I/O transactions from the primary to the secondary, addressing the last 768 bytes in each 1K-byte block. This applies only to the addresses (defined by the I/O window registers) that are located in the first 64K bytes of PCI I/O address space. From the secondary to the primary, I/O transactions are forwarded if they address the last 768 bytes in each 1K-byte block in the address range specified in the I/O window registers. Bit 2 is encoded as:

0 = Forward all I/O addresses in the address range defined by the I/O base and I/O limit registers (default). 1 = Block forwarding of ISA I/O addresses in the address range defined by the I/O base and I/O limit registers when

these I/O addresses are in the first 64K bytes of PCI I/O address space and address the top 768 bytes of each 1K-byte block.

1 R/W

SERR enable. Bit 1 controls the forwarding of secondary interface SERR assertions to the primary interface. Only when this bit is set will the bridge forward S_SERR

to the primary bus signal P_SERR. For the primary interface to assert SERR,

bit 8 of the command register (offset 04h, see Section 4.3) must be set.

0 = SERR

disabled (default)

1 = SERR

enabled

0 R/W

Parity error response enable. Bit 0 controls the bridge response to parity errors on the secondary interface. When this bit is set, the bridge asserts S_PERR

to report parity errors on the secondary interface. 0 = Ignore address and parity errors on the secondary interface (default). 1 = Enable parity error reporting and detection on the secondary interface.

5–1

5 Extension Registers

The TI extension registers are those registers that lie outside the standard PCI-to-PCI bridge device configuration space (i.e., registers 40h–FFh in PCI configuration space in the PCI2050). These registers can be accessed through configuration reads and writes. The TI extension registers add flexibility and performance benefits to the standard PCI-to-PCI bridge.

5.1 Chip Control Register

The chip control register contains read/write and read-only bits has a default value of 00h. This register is used to control the functionality of certain PCI transactions.

Bit 7 6 5 4 3 2 1 0 Name Chip control Type R R R/W R/W R R R/W R Default 0 0 0 0 0 0 0 0

Table 5–1. Chip Control Register

BIT TYPE FUNCTION

7–6 R Reserved. Bits 7–5 return 0s when read.

5 R/W

Transaction forwarding control for I/O and memory cycles. 0 = Transaction forwarding controlled by bits 0 and 1 of the command register (offset 04h, see Section 4.3) (default).

1 = Transaction forwarding will be disabled if GPIO3 is driven high.

4 R/W

Memory read prefetch. When set, bit 4 enables the memory read prefetch.

0 = Upstream memory reads are disabled (default). 1 = Upstream memory reads are enabled

3–2 R Reserved. Bits 3 and 2 return 0s when read.

1 R/W

Memory write and memory write and invalidate disconnect control.

0 = Disconnects on queue full or 4-KB boundaries (default) 1 = Disconnects on queue full, 4-KB boundaries and cacheline boundries.

0 R Reserved. Bit 0 returns 0 when read.

5–2

5.2 Extended Diagnostic Register

The extended diagnostic register is read or write and has a default value of 00h. Bit 0 of this register is used to reset both the PCI2050 and the secondary bus.

Bit 7 6 5 4 3 2 1 0 Name Extended diagnostic Type R R R R R R R W Default 0 0 0 0 0 0 0 0

Table 5–2. Extended Diagnostic Register

BIT TYPE FUNCTION

7–1 R Reserved. Bits 7–1 return 0s when read.

0 W

Writing a 1 to this bit causes the PCI2050 to set bit 6 of the bridge control register (offset 3Eh, see Section 4.32) and then internally reset the PCI2050. Bit 6 of the bridge control register will not be reset by the internal reset. Bit 0 is self-clearing.

5–3

5.3 Arbiter Control Register

The arbiter control register is used for the bridge’s internal arbiter . The arbitration scheme used is a two-tier rotational arbitration. The PCI2050 bridge is the only secondary bus initiator that defaults to the higher priority arbitration tier.

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Name Arbiter control Type R R R R R R R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W Default 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

T able 5–3. Arbiter Control Register

BIT TYPE FUNCTION

15–10 R Reserved. Bits 15–10 return 0s when read.

9 R/W

Bridge tier select. This bit determines in which tier the PCI2250 bridge is placed in the two-tier arbitration scheme.

0 = Lowest priority tier 1 = Highest priority tier (default)

8 R/W

GNT8 tier select. This bit determines in which tier the S_GNT8 is placed in the arbitration scheme. This bit is encoded as: