No, they're different layers. UART refers to the on-chip peripheral and the asynchronous framing it produces: start bit, data bits, optional parity, stop bit(s), at an agreed baud, using the MCU's logic voltage levels (e.g., 0 V and 3.3 V). RS-232 and RS-485 are electrical standards that define signaling levels and (for RS-485) differential, multi-drop wiring to carry that framing reliably over a cable, RS-232 uses bipolar voltages like ±12 V, RS-485 uses differential pairs for noise immunity over long distances. So a transceiver chip (a MAX232 for RS-232, or an RS-485 transceiver) sits between the MCU's UART pins and the cable to translate logic levels to the standard's electrical levels. The common mistake is wiring an MCU's 3.3 V UART pins directly to an RS-232 port, the ±12 V swing can damage the MCU. UART is the framing/peripheral; RS-232/485 is the physical layer.
Communication Protocols · Interview question
Is UART the same thing as RS-232?
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From the lesson
Serial vs Parallel, Sync vs Async
The two axes that classify every bus: serial vs parallel (one wire or many) and synchronous vs asynchronous (shared clock or agreed-upon rate), and where UART, SPI, I2C, and CAN land.