The USART peripheral supported by the tinyAVR® 0- and 1-series and megaAVR® 0-series has features that simplify one-wire communication. TXD and RXD can be connected internally, eliminating the need for two pins. The TXD pin is used as both input and output. The pin supports Open-Drain mode and a configurable internal pull-up, eliminating the need for external hardware. Moreover, compared to the 1-Wire bit banging example, there is minimal need for CPU cycles, and interrupts can be enabled the whole time.