A quick word on ATtiny 1-series interrupts
The Atmel AVR 8-bit microcontrollers have always been a favourite for tinkering; and the massive popularity of the Arduino based on the ATmega 168 and 328 MCUs introduced a lot of hobbyists to this series. The companion ATtiny series from Atmel were the poor stepchildren of the ATmega controllers to an extent - useful for small projects but often quite limited. However, the acquisition of Atmel by Microchip Technology in 2016 ushered in a new series of MCUs bearing the same moniker of ATtiny, but much more capable and innovative.