Migrating from 8-/16-bit to 32 bit: Lessons Learned the Hard Way

By Kavitha Sundaram, Premier Evolvics
Sep 22 2006 (12:00 PM), Embedded.com

Processors are becoming more powerful both in terms of the MIPS and the bandwidth of the data they can handle. They are equipped with most of the peripherals to make them resemble a System on a chip (SoC). As the complexity rises it is difficult to comprehend and it is necessary to move to higher abstraction levels.

The Developers become more dependent on Tools - including an IDE , Compilers, JTAG debuggers and all that "once fancy" stuff. The level of abstraction also has to be increased since it is difficult or takes a longer and steeper learning curve to have a grip on the underlying processor architecture.

Though it is attractive to jump into a 32 bit architecture from the existing 8/16 bit design capability for the amazing price- performance figures, there are hidden pitfalls which you may encounter.

The transition from 8-bit to 16-bit is not explicit since the 16-bit architectures never superseded the 8 bit Segment. Among other things 16 bit CPUs are often downsized to handle 8 bit peripherals, reducing the reduced the data throughput because of resulting I/O bottlenecks. There are also 16 bit Digital Signal Processors, which have become more popular than their 16 bit MPU conterparts because of the need to handle wider data in computation in signal processing applications.

Now we have suddenly come into an era where 32 bit processors are cheaper than 8 bit counterparts. This market push with the ever-increasing features has presented the developer with some difficult 32 bit Processor System design choices in many applications in consumer applications and additional features, connectivity and in Industrial Applications.

There are a few cores that have gained wide use and licensing across different vendors. Indeed, the ARM 7 and ARM 9 cores have been considered the "8051 Core" of this decade based on the popularity and availability from different vendors.

There are some specific advantages in choosing such widely available architectures. A developer can switch across different vendors for any upgrade or additional features. There is usually a roadmap associated with the hardware from a specific vendor but also a migration path across different vendors.

Another advantage is the Skill Set available in working with these popular cores. This helps reducing the learning curve and initial startup delays. These skills can also be used across different applications and hence the initial Setup Costs for the Tools could be amortized across different products under development.

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