PCI Bus Transactions

5

This chapter presents the theory of operation information about PCI transactions. See Chapter 16 for specific information about PCI registers. The following sections are discussed:

•Section 5.2, “Posted Write Transactions” on page 50.

•Section 5.3, “Delayed Write Transactions” on page 54.

•Section 5.4, “Delayed Read Transactions” on page 55.

•Section 5.5, “64-Bit and 32-Bit Transactions Initiated by the 21555” on page 59.

•Section 5.6, “Target Terminations” on page 60.

•Section 5.7, “Ordering Rules” on page 61.

5.1Transactions Overview

The 21555 responds to transactions using these commands as a target on both interfaces. The 21555 does not respond to transactions using any other PCI commands.

•All memory commands.

•Dual-address commands.

•I/O read and write commands.

•Type 0 configuration commands.

The 21555 can initiate transactions using the Type 0 and Type 1configuration commands on either interface.

The 21555:

•Responds to transactions by asserting DEVSEL# with medium timing.

•Can subtractively decode I/O transactions in the primary direction only.

•Supports linear increment address mode only and disconnects memory transactions whose low two address bits are not 00b after a single Dword.

21555 Non-Transparent PCI-to-PCI Bridge User Manual

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Intel 21555 user manual PCI Bus Transactions, Transactions Overview
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21555 specifications

The Intel 21555 is a prominent microprocessor developed by Intel, designed to cater to a variety of computing needs. This processor marks a significant step forward in Intel's lineup and underscores the company's commitment to advancing technology in personal computing, enterprise solutions, and beyond.

One of the standout features of the Intel 21555 is its advanced architecture. It utilizes a multi-core design, enabling improved performance through parallel processing. This architecture allows multiple applications to run seamlessly without a decline in speed. The cores are built on a cutting-edge manufacturing process that enhances energy efficiency while maintaining high clock speeds.

The Intel 21555 supports a wide range of technologies, including Intel Turbo Boost, which enables dynamic adjustments to the processor’s performance based on workload demands. This feature allows the processor to accelerate its speed during intensive tasks, providing users with a responsive experience when it matters the most.

Another key characteristic of the Intel 21555 is its support for integrated graphics. With Intel UHD Graphics technology, users can enjoy enhanced visuals for everyday tasks such as video playback, web browsing, and light gaming. This eliminates the need for a separate graphics card for many users, particularly in home office or light gaming scenarios.

Security is a significant focus in the design of the Intel 21555. It includes built-in hardware-based security features like Intel Trusted Execution Technology and Secure Boot. These features help protect against various types of threats, ensuring that user data remains secure from malicious attacks.

The Intel 21555 is also optimized for use with Intel's platform technologies, including Intel Optane memory and Intel Rapid Storage Technology. These technologies work together to deliver faster boot times and improved system responsiveness, making computing more efficient for users.

Furthermore, the Intel 21555 is designed to support virtualization technologies, allowing multiple operating systems to run concurrently without compromising performance. This is particularly useful for developers and businesses that rely on virtualization for testing and development environments.

In summary, the Intel 21555 is a powerful and versatile processor that reflects Intel's ongoing innovation in the computing space. With its multi-core architecture, enhanced graphics capabilities, strong security features, and advanced technologies, it stands out as an excellent choice for a wide range of applications, serving both casual users and professionals alike.
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