David Hess (davidwhess.delete@this.gmail.com) on March 7, 2013 6:30 pm wrote:
[snip]
> I thought your question deserved a better answer so I spent some time going back over
> my notes and currently available ARM microcontrollers including the new Cortex designs
> that would be suitable. Here are some of my complaints in no particular order:

Thank you for taking that extra effort! I hope I am not the only beneficiary!

The packaging and memory capacity issues seem like they would be easy to solve technically, but I could see that targeting high-volume uses (where BGA might be more attractive [guessing, forgive my ignorance]) might delay the descent of ARM into such forms.

With respect to pricing, it is not clear what makes the pricing that much higher. 32-bit processors might well be more attractive to certain developers new to microcontrollers, which might allow some premium to be charged. I would also guess that the Cortex-M core licenses might decrease in price somewhat over time, but I was under the vague impression that such only accounted for a tiny fraction of the product cost--even with tight margins in the microcontroller market, such would seem unlikely to account for a 4x difference.

I seem to recall reading that ARM was working on a more direct connection between the core and peripherals, but I could see ARM (and those using ARM cores) not making that an especially high priority as existing Cortex-M products are doing very well and 8- and 16-bit processors are very unlikely to move upward. (There might be some threat to future ARM downward migration if 8- or 16-bit processors become established in certain domains that became popular, especially for something like implanted medical devices for which changing the processor might require a complete revalidation of the system.)

(I thought it would be neat if a 32-bit processor could be used in a 16-bit mode, possibly even using the upper 16-bits for a secondary thread. The idea of a scalable/flexible implementation [and ISA/family of architectures] has some appeal to me, whether such is technically or economically practical is a different matter.)

It sort of sounds like the ARM microcontroller vendors might be taking the most attractive portions of the microcontroller market and not bothering with some less profitable areas. The vendors behind established alternatives which do address these areas may not have much incentive to adopt ARM, especially if it makes migrating to a competitor's ARM-based products easier and encourages other customers to move to a vendor that is perceived as more firmly standing behind its legacy 8- or 16-bit products (and even paying 1% of revenue to ARM may be unattractive).

Again, thank you for providing an insight into certain Real World Technologies--especially technologies where information is more scarce than for PCs and smart phones.