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Groups > comp.lang.python > #10874

Re: problem with bcd and a number

Date 2011-08-04 20:35 +0100
From MRAB <python@mrabarnett.plus.com>
Subject Re: problem with bcd and a number
References <31c8d075-2901-46eb-adcf-1c1803ab7938@a4g2000yqg.googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.1901.1312486523.1164.python-list@python.org> (permalink)

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On 04/08/2011 19:26, nephish wrote:
> Hey all,
>
> I have been trying to get my head around how to do something, but i am
> missing how to pull it off.
> I am reading a packet from a radio over a serial port.
>
> i have " two bytes containing the value i need.  The first byte is the
> LSB, second is MSB.  Both bytes are BCD-encoded, with the LSB
> containing digits zX and MSB containing digits xy.  The system speed
> is then xyz%, where 100% means maximum speed and would be given by
> bytes 00(LSB) 10(MSB)."
>
> that is a quote from the documentation.
> Anyway, i am able to parse out the two bytes i need, but don't know
> where to go from there.
>
> thanks for any tips on this.

The value is MSB * 100 + (LSB >> 4) * 10 + (LSB & 0xF)

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Thread

problem with bcd and a number nephish <nephish@gmail.com> - 2011-08-04 11:26 -0700
  Re: problem with bcd and a number Ethan Furman <ethan@stoneleaf.us> - 2011-08-04 12:44 -0700
  Re: problem with bcd and a number MRAB <python@mrabarnett.plus.com> - 2011-08-04 20:35 +0100
    Re: problem with bcd and a number Christoph Hansen <ch@radamanthys.de> - 2011-08-04 21:52 +0200
      Re: problem with bcd and a number Peter Pearson <ppearson@nowhere.invalid> - 2011-08-05 16:01 +0000
  Re: problem with bcd and a number Ethan Furman <ethan@stoneleaf.us> - 2011-08-04 13:14 -0700

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