Editing Automatic baud rate detection (section)

==Process==
During the autobaud process, the [[Symbol rate|baud rate]] of received character stream is determined by examining the received pattern and its timing, and the length of a start bit. These type of baud rate detection mechanism are supported by many hardware chips including processors such as STM32<ref>[https://www.st.com/content/ccc/resource/technical/document/application_note/group0/66/fa/62/a2/5c/75/48/a8/DM00327191/files/DM00327191.pdf/jcr:content/translations/en.DM00327191.pdf STM32 USART automatic baud rate detection]</ref> MPC8280,  MPC8360, and so on.  

When start bit length is used to determine the baud rate, it requires the character to be odd since UART sends [[least-significant bit|LSB]] bit first{{snd}}this particular bit order scheme is referred to as [[Endianness|little-endian]].<ref>{{Cite web |title=MIT — 6.111 Introductory Digital Systems Laboratory |url=https://web.mit.edu/6.111/volume2/www/f2019/handouts/lpset_2.pdf |access-date=July 15, 2023 |website=MIT 6.111 Fall 2019}}</ref> Often [[ASCII]] symbols 'a' or 'A' (0x61 or 0x41) are used. For example, the MPC8270 SCC tries to detect the length of the UART start bit for autobaud.

Many protocols begin each frame with a preamble of alternating 1 and 0 bits that can be used for automatic baud rate detection. For example, the TI PGA460 uses a ASCII ''U'' ({{Hexadecimal|85}} or {{Binary|85}}) sync byte for automatic baud rate detection as well as [[frame synchronization]],<ref>
"Sync Field" section of
[https://www.ti.com/lit/ds/symlink/pga460.pdf "PGA460 Ultrasonic Signal Processor and Transducer Driver"].
2017.
p. 35.
</ref> and so does the LIN header ([[Local Interconnect Network#Header]]).

For example, the UART-based FlexWire protocol begins each frame with a ''U'' ({{Hexadecimal|85}}) [[sync byte]]. FlexWire receivers use the sync byte to precisely set their UART bit-clock frequency without a high-precision oscillator.<ref>
Texas Instruments.
[https://www.ti.com/lit/ds/symlink/tps929121-q1.pdf "TPS929121-Q1 12-Channel Automotive 40-V High-Side LED Driver With FlexWire"].
2021.
p. 37 and p. p. 39.
</ref> For example, the [[Ethernet frame#Preamble and start frame delimiter | Ethernet preamble]] contains 56 bits of alternating 1 and 0 bits for synchronizing bit clocks.