That which does not kill us makes us stronger. Which is why the 8051 persists.

Even then, you can always write classes for debug (if doing C++), or write handlers for semihosting/breakpoint exceptions (for C/C++) to enable debug.

One interesting point is that now you can export the mbed project to gcc, uVision and several other non-cloud compilers.

- Jonny

Back to Robert’s original question, Architecture and tools influence what I want but on high volume, size constrained projects, cost, chip size, power and operations/manufacturing requirements often dictate what I get

@Alexander:
I thought of the M0 because it’s a simpler part but I like Jonny’s points about the M3.
The mbed board is fun. You can do a lot with it quickly and it’s very easy to set up since you don’t have to install any tools and do everything from your web browser. But, you don’t have a debugger and can’t set breakpoints, examine registers, step through code, etc. That may have changed since I tried one last Fall.

I’d like to add to @Rich very good suggestions on ARM Cortex-M0. I would expand and suggest a Cortex-M3 instead. This is why:

- The Cortext-M0 is actually a very architecturally constrained subset of the ARMv7-M architecture. Its cut-down instruction set is not exemplar of ARM architecture, and has several shortcomings. To use the -M0 16bit THUMB dialect to teach ARM assembly is not very productive, because it is much harder to produce any decent assembly programming on that subset, and it is not as easy to understand.
- The -M3, on the other hand, has a superb instruction set, the 32bit/16bit THUMB2, with many traits derived from the extremely powerful 32bit ARM instruction set. Actually, even the ARM7TDMI-s is a better candidate for teaching, due to the ARM ISA and a simple architecture that scales very well to the ARMv7-AR.
- These cores (ARM7 and Cortex-M3) can be used to teach current embedded computing, using a solid base of Assembly to build on, and using ARM tools, that are among the best you can have in terms of optimizing compiler, full C99 compliance, no-constraints programming, and very wide availability, with literally dozens of manufacturers and proper kits to chose from.
- Almost any ARM-based uC is loaded with a nice pack of peripherals, and can be used for a serious embedded computing platform.
- Take a look at the mbed boards, from NXP, with a free cloud-based C/C++ compiler. The compiler is actually the ARM RealView compiler, made to run on the cloud. It is perfect for teaching purposes.

- Jonny

However, from the standpoint of the embedded designer, unless you are really hard pressed in an overexploited commodity market, there is no gap whatsoever for taking an ARM as your next target….

- Jonny

I would consider
TI MSP430 or the ARM Cortex M0
They have a clean architecture
Small regular instruction set (easy to learn)
Support C well (the compiled C code is easy to follow along side the source)
Lots of sample code, documentation and books
Inexpensive demo boards
If you later want get into RTOSes, you can. (after all, this is the Real Time Embedded Group)

For more complex applications, the debugging support being built into some of the 32 bit controllers is a big advantage over the 8 bit parts. The CoreSight debugging architecture in some of the ARM controllers has a lot of impressive features. Debugging tools are just as important as the rest of the tools.

As a matter of fact, when you compare the IDEs used in embedded systems to the standard used in desktop and mobile systems, they all fall short.

- Jonny