auto baud rate detection at pic18

Discussion in 'Embedded Systems and Microcontrollers' started by bug13, Mar 17, 2015.

  1. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
    1,208
    38
    Hi guys

    I came cross this on a datasheet (auto bard rate detection), I have never used it, but I think it's something very nice to have in a design.

    Just wondering, what's the pros and cons of this?
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,136
    1,786
    It normally depends on having source of characters with particular characteristics to measure. If the incoming character is odd, that is LSB = 1, then you can measure the length of the START bit. The Carrige Return character has this property. If there are no incoming characters, then baudrate cannot be determined, but who cares? Well maybe you do if you want to talk to the device before it talks to you.

    I suppose you could also try all available baudrates until you found one that worked. Selecting the search order would be the challenge especially if the device could operate at more than one rate.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,509
    2,369
    I have some programs that came with the Picmicro F18's and F30's BLDC development board Picdem LV MC that includes auto baud rate detection for the PC based tuning program.
    They are usually available for download with the board details on the site.
    Max.
     
  4. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
    1,208
    38
    It sounds like I should stick with a fixed baud rate design. Thanks guys!
     
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