Using the new ATtiny Processors with Arduino IDE - Hackster.io
A simple and inexpensive way to program new AVR ATtiny214, ATtiny414, ATtiny814 and Atmega microcontrollers using by the UPDI interface - ООО "НПК "Спецтехнаука"
use UPDI line for serial comunication with my computer · SpenceKonde megaTinyCore · Discussion #501 · GitHub
Solved: ATTiny 414 & Using 32 kHz External Crystal for Waveform Generation (TCA & TCD)
Programming the new ATtiny from Arduino using UPDI [Beginner Tutorial] - YouTube
A simple and inexpensive way to program new AVR ATtiny214, ATtiny414, ATtiny814 and Atmega microcontrollers using by the UPDI interface - ООО "НПК "Спецтехнаука"