Embedded Systems Academy

I was visiting Embedded World this week and in regards to microcontrollers the trend towards 32bit continues. When it comes to marketing presence at a trade show, obviously less than 32bit where not “it” this year. Not only chip manufacturers, but also most of the development tools primarily focused on 32bit solutions. And the next impression one gets walking the aisles: ARM processors are the first choice in this arena, with a focus on the Cortex-M generation. At this year’s Embedded World, no other microcontroller architecture had a marketing presence anywhere near that of ARM.

After the ARM7 and ARM9 generation it is now the ARM Cortex-M processors that are going broad market, more and more chip manufacturers offer and promote derivatives of this architecture. One of the leading “embracers” of the Cortex-Mx is NXP. On the lowest end of this family NXP offers Cortex-M0 derivatives which are aimed at replacing 8 and 16bit microcontrollers and are best suited for lowest power applications. The Cortex-M3 devices are considered mid range and on the high end is the Cortex-M4 offering DSP extensions. Note that the Cortex-M4 was just recently announced and it will take a while until implementations become widely available.

As a tutor conducting various ARM trainings and being involved in tests, benchmarks and reports I am always amazed about how this industry works when promoting performance differences between microcontrollers. Looking at ARM7, ARM9 and Cortex-M variants they indeed have a different performance at the same clock rate, but none of these differences come even close to a factor of two.

In our report Performance Considerations for ARM processor based developments (available at www.esacademystore.eu) we outline where the really big traps and gaps are when trying to boost real-world performance, and it’s not the architecture sub-species. We can show that single decisions that engineers make when developing an embedded application can impact the performance by a factor of ten or more. Selecting a specific ARM processor architecture versus another family pales by comparison.

Of course, there are always some applications where exactly that difference is the one needed to make it work. But for the most part, the majority of embedded applications  do not have a very specific performance need and any ARM based microcontroller will do the job and more. Unless, of course, one makes too many bad choices in designing the application. Even the best processor performance can be nullified by poor software!

So even if ARM processors are now “everywhere”, for developers of embedded systems the selection criteria is the same as always: good development tools, right peripheral mix, availability, pricing, trusted partners – your priorities may vary…