The RS485 to UART series requires a dedicated interface chip, such as MAX485 and SP485. This chip is to convert the balanced differential signal of 485 and the receiving and receiving level signal of the serial port to each other, so as to achieve UART to 485.
In addition to signal conversion, the 485 interface chip has an enable end, which is used to control whether the interface chip is in the receiving or sending state, and it is necessary to pay attention to the logic function of this pin when programming.