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Many consumer devices that require a low-power processor capable of running for several days to a few weeks on a charge still use ARM9 or ARM11 processors. However, the ARM Cortex-A5 is more powerful and more efficient, is capable of running modern ARMv7 applications, and is intended to replace ARM9 and ARM11 for these uses. (I'm seeing this on devices where signal processing is not as important as applications performance, such as high-end graphing calculators; devices such as low-cost MP3 players and portable DVD players are best served with the Cortex-M series.)

Why are device manufacturers still using these old ARM cores when a more efficient processor exists? If a high clock rate (> 600-800 MHz) isn't required, why aren't they just using a low-clocked Cortex-A5 manufactured on an ultra-low-leakage process for efficiency? (And yes, there are low-clocked Cortex-A5 processors out there.)

bwDraco
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2 Answers2

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Migrating an application from one processor family to another requires lots of planning and design changes. That in turn equates to a certain cost to migrate.

Following are a few factors involving costs:

  • Physical redesign
  • Code redesign
  • Testing
  • Skills acquisition

ARM has a roadmap for migrating from ARM9 to Cortex.

In a nutshell, cost is the biggest reason why manufacturers stick to older designs.

bwDraco
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Chetan Bhargava
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Basically, Higher cost of newer parts, cost of reengineering a board or starting from scratch, cost of software revisions to support new & different hardware, and cost of retooling existing productions or new lines of production.

And if they don't need the extra processing power or the negligible amount of power efficiency gains, why bother.

Passerby
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