Clocking

7.366 MHz Support

The 21555 supports 66 MHz operation. It has two pins, p_m66ena and s_m66ena, that indicate whether the primary and secondary bus are operating at 66 MHz, respectively. Signal p_m66ena is an input-only pin.

•When sampled high, the primary bus is assumed to be operating at 66 MHz.

•When sampled low, the primary bus must be operating at or below 33 MHz. Signal s_m66ena is an input/ open-drain pin.

•When sampled high, the secondary bus is assumed to be operating at 66 MHz.

•When sampled low, the secondary bus must be operating at or below 33 MHz.

The 21555 pulls s_m66ena low when the primary bus is operating at 33 MHz (p_m66ena low) and s_clk_o is enabled. When s_clk_o is enabled, it is assumed that the 21555 is controlling the clocking of the secondary bus and since s_clk_o is a buffered version of p_clk, it must operate at

33 MHz.

When p_m66ena is sampled high, s_m66ena is sampled low, and s_clk_o is enabled, the 21555 divides s_clk_o by 2 to generate a 33Mhz clock.

The 21555 can handle any combination of clock frequencies between primary and secondary buses with the maximum clock ratio between primary and secondary buses being 2.5:1 (for example 25 MHz on one bus and 66 MHz on the other), and a maximum frequency of 66 MHz.

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Intel 21555 user manual MHz Support
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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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