Process flow of UART for beginners

Process flow for configuring a UART in a microcontroller involves several steps,

    • Initialize the UART peripheral

    • Configure the UART

        ◦ Baud Rate

        ◦ data bits

        ◦ Stop bits

        ◦ Parity

        ◦ interrupt based or blocking?

    • Test the UART with loop back between Tx and Rx

    • Transmit or Receive the data

What happens during the UART data transmission?

    • DATA to be sent is copied to TX Buffer

    • Loads byte into shift register

    • Sends bits serially on TX pin

What happens during the UART data receive?

    • DATA is sampled on RX pin

    • Byte is constructed

    • Byte is placed in RX FIFO

In UART, interrupt-driven communication uses hardware interrupts to signal the CPU only when data is ready (receive) or sent (transmit), letting the CPU do other work; this is efficient and non-blocking. Blocking (or polling) communication means the CPU must constantly check the UART status register (busy-wait) until data is ready, halting other tasks until the check passes, which wastes CPU cycles.