Intel XScale Microarchitecture, Debugging

SA-1110/Applications Processor Migration

A.3.1 Intel® XScale™ Microarchitecture

The PXA250 applications processor is a system on a chip that includes Intel’s new microprocessor megacell. This includes Intel® Superpipelined Technology and a new optimized cache architecture that allows program execution to continue despite data cache misses.

The PXA250 applications processor supports:

•ARM* Architecture v5 instructions, including ARM’s Thumb extensions

•DSP Extensions but not ARM’s optional Vector Floating Point instructions

Appendix A in the Intel 80200 Developers’ manual, Order# 273411-002 [http:// developer.intel.com], is the best guide to the new capabilities available in the Intel® XScale™ Megacell's Instruction Set.

Using a software development toolset that takes specific advantage of Intel® XScale™ microarchitecture, and Intel® Media Processing Technology could give you substantial performance benefits.

The PXA250 applications processor offers increased performance at similar clock rates, and also a wider range of operating clock rates at lower voltages. The overall benefit is more work done for less battery power.

A.3.2 Debugging

New PXA250 hardware creates new debugging possibilities. You can use the JTAG test port to download programs into a dedicated memory area to act as a debug monitor. Applications can be inspected and performance data, such as cache hit rates, can be measured via a dialog over JTAG. These features offer developers far more visibility inside a PXA250 system improving time to market.

A.3.3 Cache Attributes

The PXA250 applications processor has twice the instruction cache and four times the data cache of the SA-1110. The Caches can be locked for optimized code or data and for reliability the caches are now covered by parity protection.

To take advantage of cache locking software, data must be selected and specifically loaded and locked into cache.

To take advantage of new features such as Write-Through mode for external IO buffers, page tables will need to be revisited in boot software.

A.3.4 Other features

As mentioned before, the PXA250 DMA controller is highly versatile. With 16 channels it can be utilized as:

•Several serial ports in parallel

•A general-purpose memory move capability

•A fast interface for external companion devices

A-8	PXA250 and PXA210 Applications Processors Design Guide

PXA250 and PXA210 specifications

The Intel PXA250 and PXA210 processors, part of the Intel XScale architecture, were introduced in the early 2000s, targeting mobile and embedded applications. They are known for their low power consumption, high performance, and advanced multimedia capabilities, making them suitable for a wide range of devices, including PDAs, smartphones, and other portable computing devices.

The PXA250, which operates at clock speeds ranging from 400 MHz to 624 MHz, features a superscalar architecture that allows it to issue multiple instructions per clock cycle. This enhances the overall performance for demanding applications while maintaining low power usage. It supports a variety of peripheral interfaces, including USB, Ethernet, and various memory types, which contributes to its versatility in different product designs.

One of the key technologies in the PXA250 is the integrated Intel Smart Repeat Technology, which optimizes data processing, thereby reducing the amount of power consumed during operation. This feature is particularly important for battery-powered devices, as it extends the overall battery life, allowing for longer usage times in mobile environments. Additionally, the PXA250 includes a dedicated graphics acceleration unit, which enables enhanced graphics and multimedia performance suited to modern applications at the time.

In contrast, the PXA210 is a more entry-level processor, aimed at cost-sensitive applications. Operating at lower clock speeds, typically around 200 MHz to 400 MHz, it forgoes some of the advanced performance features of the PXA250 while still offering a good balance of performance and power efficiency. The PXA210 is less complex, making it suitable for simpler devices that do not require the extensive capabilities of the PXA250.

Both processors utilize the Intel XScale architecture, which is based on the ARM instruction set. They are built on a 0.13-micron process technology, enabling higher density and lower power consumption compared to their predecessors. With integrated memory controllers and bus interfaces, they facilitate efficient data handling and connectivity options.

In summary, both the Intel PXA250 and PXA210 processors played a crucial role in the evolution of mobile computing by providing powerful processing capabilities with energy efficiency. Their features and technologies enabled device manufacturers to create innovative products that catered to the growing demand for portable devices during that era.

Intel PXA250 and PXA210 manual Intel XScale Microarchitecture, Debugging, Cache Attributes

Models: PXA250 and PXA210