ATtiny1634: My ATtiny is bigger (smaller) than yours

The ATtiny1634 microcontroller has an interesting combination of features:

• 16K of flash memory, the most of any ATtinys (And matching the ATmega168 used in older Arduinos).
• Up to 18 digital I/O pins (close to the 20 you’d get on an Arduino).
• Two hardware UARTS (optionally usable as SPI ports), vs. 1 each on an ATmega328 / Arduino.
• 12 analog inputs (vs 6 on an ATmega328).
• 4 PWM outputs (vs 6 on an ATmega328).

As opposed to the commonly used ATtiny85 / ATtiny84, the ATtiny1634 is only available in SMD packages. The SOIC package is a bit smaller than an ATtiny84 PDIP package, but if you want a truly small package, the ATtiny1634 is also available as a WLCSP package, squeezing its 20 pins into a 2mm*2.38mm ball grid pac (this could get slightly finicky to handle).

I’ve modified the arduino-tiny core to add support for the ATtiny1634 (Edit: Moved from Google code to Github in 2015). Additionally, you also need an upgraded avr-gcc toolchain. On the Mac, I recommend AVR-Crosspack, which can also be retrofitted into the Arduino IDE.