Microcontroller discerns addresses in RS-485 systems

摘要

One of the many benefits of using the RS-485 data-interface system, unlike the RS-232 system, is its ability to implement multidrop networks. Such networks usually carry 9-bit data words, in which the ninth (parity) bit identifies each word as address or data. When using small microcontrollers without a hardware UART, such as IC_1 in Figure 1, designers must decide whether to add an external hardware UART or to configure a UART in software.