Comparing 21 sub-$1 microcontrollers

In 2017, we saw several new MCUs hit the market, as well as general trends continuing in the industry: the migration to open-source, cross-platform development environments and toolchains; new code-generator tools that integrate seamlessly (or not so seamlessly") into IDEs; and, most notably, the continued invasion of ARM Cortex-M0+ parts into the 8-bit space. I wanted to take a quick pulse of the industry to see where everything is - and what I've been missing while backed into my corner of DigiKey's web site. It's time for a good ol' microcontroller shoot-out.