For 2¢ you can add several more I/O pins...
For 2¢ / ATtiny84 ... Those are nice.
I'm assuming they are programmed in the same way.
This is my DIY "arduino", although is little more than a breaduino on a PCBEDuino
Hey, good work on that LCD IO Backpack board! So you guys are making workshops around it?
Why 16 MHz? Why not 20 MHz for 20 MHz-capable chips? Does that make the rest iffy?