Parallel ROM Interface

8.4PROM Write by CSR Access

Byte writes of the PROM can be performed by CSR access of the Table 112, “ROM Control Register” on page 178, Table 111, “ROM Address Register” on page 178, and Table 110, “ROM Data Register” on page 177. A byte write is performed as follows:

1.The initiator writes the byte address offset to the ROM Address register.

2.The initiator writes one byte of write data into the ROM Data register.

3.The initiator writes the PROM Start bit to a 1, Serial ROM Start bit to a 0, and the ROM Read/Write Control bit to a 1 in the Table 112, “ROM Control Register” on page 178 This can be done with the same CSR access.

4.When the initiator reads the PROM Start bit in the Table 112, “ROM Control Register” on page 178 as a 0, the access is complete.

When a byte write to the PROM is performed, the 21555 follows this sequence on the ROM interface, also shown in Figure 16:

1.The 21555 drives address bits [23:16] on the pr_ad[7:0] pins and asserts the address register enable, pr_ale_l.

2.The 21555 drives pr_clk high, latching address bits [23:16] into the first external register.

3.The 21555 drives pr_clk low.

4.The 21555 drives address bits [15:8] on the pr_ad[7:0] pins.

5.The 21555 drives pr_clk low, latching address bits [15:8] into the first external register, and address bits [23:16] into the second external register.

6.The 21555 drives pr_clk low.

7.The 21555 drives address bits [7:0] on the pr_ad[7:0] pins.

8.The 21555 drives pr_clk high, latching address bits [7:0] into the first external register, address bits [15:8] into the second external register, and address bits [23:16] into the third external register. All the ROM address and control bits are now driven to the appropriate ROM pins.

9.The 21555 deasserts the address register enable, pr_ale_l.

10.The 21555 drives the write data on pr_ad[7:0].

11.The 21555 asserts the pr_cs_l and pr_wr_l pins according to the strobe setup timing specified by the Strobe Mask in the ROM Setup register.

12.The 21555 deasserts pr_wr_l according to the strobe timing in the ROM Setup register, and deasserts the pr_cs_l according to the access time in the ROM Setup register.

13.The 21555 clears the PROM Start bit in the Table 112, “ROM Control Register” on page 178.

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

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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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