It’s admittedly pretty specialized, but there’s very little accessible information out there about ARM assembly in general (documentation from ARM always feels sadly neglected and half-hearted to me), but I came across this wonderfully precise and accessible summary of inline ARM assembly with GCC that really surprised me. It’s not something you’ll use all the time even if you do a fair amount of development on ARM, but it’s a treasure chest of information if you’re trying to figure out how to optimize some particularly picky function: ARM GCC Inline Assembler Cookbook.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.