2 Background Information

One-wire communication can be done in multiple ways. Here, the focus will be on one-wire communication using USART. USART is a communication peripheral which uses two pins: one for reception (RXD) and one for transmission (TXD). When the USART is used for one-wire communication, TXD and RXD need to be connected to each other.

Communication in electrical systems can be divided into three categories: simplex, half duplex, and full duplex. With simplex communication, data travel in only one direction. With half-duplex communication, data can travel in both directions but not at the same time. With full-duplex communication, data can travel in both directions at the same time.

With most types of one-wire communication, simplex or half duplex is used. Simplex is easiest to implement and does not require any special considerations for the USART, while half duplex adds complexity as time multiplexing of communication must be handled by software, and RXD and TXD will be connected together on the same device.