Developing for ARM MCU platforms isn't significantly different from developing for AVR MCUs, except that C++ is far better supported, and there exists a wide range of toolchains to choose from, as we saw at the beginning of this chapter with just the list of popular IDEs. The list of available RTOSes for Cortex-M is much larger than for AVR or ESP8266 as well.
Using a free and open source compiler including GCC and LLVM to target a wide range of ARM MCU architectures (Cortex-M-based and similar) is where developing for ARM MCUs offers a lot of freedom, along with easy access to the full C++ STL (though one might want to hold off on exceptions).
When doing bare-metal development for Cortex-M MCUs, one may have to add this linker flag to provide basic stubs for some functionality that is normally provided by the OS:
-specs=nosys.specs
One thing that makes...
