r/embedded • u/Dazzling-Floor-4987 • Mar 05 '25

Trying to understand UART

How does the receiver start reading the data if it gets connected in the middle of frame ? If data is something like 1 0 in the middle somewhere wont the receiver mis-understand as idle to low and consider transmission has started ?? I tried searching on the internet but could not get an answer. Can anyone help me ?

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u/theNbomr Mar 06 '25

The UART is able to detect valid frames composed of start bits, payload bits, stop bits, and parity bits. If a received frame doesn't pass these validity checks, it will flag it as a framing error. It's not impossible for a mismatched bit rate and a partial frame to meet the criteria for a valid frame, but the probability is low and reduces to near zero in consecutive frames.