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frame size and possible baud rate

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fLY bOI
2007-11-03
2013-05-20
  • fLY bOI

    fLY bOI - 2007-11-03

    First of all, I thank you for such a useful driver.

    I've been trying to study how the code works with my limited knowledge of driver
    development and I had a few questions.

    I see the use of KeSetTimerEx where I believe the smallest period is 1ms. will that be the case for when baudrate emulation turned off?

    and could you be so kind to explain the concept of a frame?
    for example does 100 decibits per frame mean 1000bits per frame or 10 bits per frame? or just 100 bits per frame?
    and is this the amount of bits written to a buffer at once?

    What is the highest theoretical baud rate achievable? (with baud rate emulation and not
    considering the wait time of a DPC call)
    For example if it's 100 decibits per frame and dueTime and period of timer is 1
    then is the achieved baud rate 1000000 bps?

    Thank you!

     
    • Vyacheslav Frolov

      > I see the use of KeSetTimerEx where I believe the smallest period is 1ms.
      > will that be the case for when baudrate emulation turned off?

      No.

      > and could you be so kind to explain the concept of a frame?

      The frame includes start bit, data bits, parity and stop bits.

      > for example does 100 decibits per frame mean 1000bits per frame or 10 bits per
      > frame? or just 100 bits per frame?

      100 decibits per frame mean 10 bits per frame.

      > and is this the amount of bits written to a buffer at once?

      No. The amount of bytes (not bits) written to a buffer at once is adaptive (see GetWriteLimit).

      > What is the highest theoretical baud rate achievable? (with baud rate emulation
      > and not considering the wait time of a DPC call)

      It's limited by ULONG max value.

      > For example if it's 100 decibits per frame and dueTime and period of timer is 1
      > then is the achieved baud rate 1000000 bps?

      No.

       

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