Upstream I/O or Memory Setup | Intel 21555 specs

List of Registers

Table 43. Downstream I/O or Memory 1 and Upstream I/O or Memory 0 Setup Registers

These registers may be preloaded by serial ROM or programmed by the local processor before host configuration.

	Offsets			Downstream I/O or Memory 1 Setup	Upstream I/O or Memory 0
	Offsets			Downstream I/O or Memory 1 Setup	Setup
					Setup

	Primary byte			B3:B0h	C7:C4h

	Secondary byte			B3:B0h	C7:C4h


	Bit	Name	R/W	Description

		Type		• When 0, the BAR is requesting memory space, or is disabled.
0		Type	R/(WS)	• When 1, the BAR is requesting I/O space.
0		Selector	R/(WS)	• When 1, the BAR is requesting I/O space.
		Selector		• Reset value is 0
				• Reset value is 0

				Type of space requested. Allowable values:
				• 00b to indicate that the space requested by the BAR may be located
				anywhere in memory space, must be used for I/O space
2:1		Type	R/(WS)	• 01b to indicate that memory space must be mapped below a 1MB
				boundary
				Other values may have unpredictable results.
				Reset value is 00h.

				Indicates whether the space requested by the BAR is prefetchable.
				• When 0, not prefetchable (required, but not hardware enforced, for I/O
3		Prefetchable	R/(WS)	space).
				• When 1, prefetchable.
				• Reset value is 0

5:4		Reserved	R	Read only as 0.

				These bits specify the size of the address range requested by the BAR.
				• When a bit is 1, the corresponding bit in the BAR functions as a
				readable and writable bit.
				• When a bit is 0, the corresponding bit in the BAR functions as a
30:6		Size	R/(WS)	read-only bit that always returns zero when read.
30:6		Size	R/(WS)	The PCI Local Bus Specification, Revision 2.2 states that the maximum

				value requested for I/O space should not be greater than 256 bytes,
				although this is not enforced in hardware. When configured as a memory
				range, bits [11:6] should be set to a 0 as the minimum supported memory
				range is 4KB.
				• Reset value is 0 (disabled).

				BAR enable.
				• When 0, the corresponding BAR is disabled and reads as 0.
31		BAR_Enable	R/(WS)	• When 1, the corresponding BAR is enabled, with size and type
				specified by this setup register.
				• Reset value is 0

138	21555 Non-Transparent PCI-to-PCI Bridge User Manual

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.

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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.

Intel 21555 user manual Upstream I/O or Memory Setup

Models: 21555

Offsets

Upstream I/O or Memory 0

Setup

Bit

21555 specifications