Re: Slider with Checksum

What kind of TV is it? I just recently wrote a plugin for eventghost
for mitsubishi and a samsung, one of which required a twos compliment
checksum.

On Feb 12, 3:20 am, "Karl Addrison" <k...@addrison.co.uk> wrote:
> You are forgetting to add 1
>
> The inverse of 3B is C4 you then need to add one
>
> You will also have to be carefully when it goes over 255 if the checksum is
> only 1 byte
>
> In finding the two's complement of a binary number, the bits are inverted,
> or "flipped", by using the bitwise NOT operation; the value of 1 is then
> added to the resulting value.
>
>
>
> -----Original Message-----
> From: commandfusion@googlegroups.com [mailto:commandfusion@googlegroups.com]
>
> On Behalf Of stbluesrul
> Sent: 12 February 2010 08:22
> To: CommandFusion
> Subject: Re: Slider with Checksum
>
> For the string \x08\x22\x01\x00\x00\x10 the checksum is C5
>
> It's the 2's complement of the sum of all the values (That's what the
> manual says).  Now the way I understand this, is that it is basically
> the sum of
> (08+22+01+00+00+10) = 3B
> Then take the inverse of 3B which is C5
>
> I have an excel spreadsheet that can calculate this.  You can also do
> this in the windows scientific calculator.  I can email you
> spreadsheet if you like.
>
> Here are the steps in the windows scientific calculator:
> 1)  Scientific mode
> 2)  Set to Hex
> 3)  Set to Byte
> 4)  Add up 08+22+01+00+00+10
> 5)  Should = 3B
> 6)  To get the inverse simply click the "+/-" button and the output
> should be C5
>
> On Feb 11, 6:27 pm, Jarrod Bell <jar...@guilink.com> wrote:
> > I believe this will be possible in an upcoming release that allows for
> > math expressions within commands.
>
> > Could you post how to mathematically calculate the checksum for the
> > protocol above? Then I can ensure our math system (which is already
> > working in our beta builds) will be able to do this.
>
> > Jarrod
>
> > On Feb 12, 12:00 pm, stbluesrul <paul.l.cra...@gmail.com> wrote:
>
> > > Is it possible to use the slider with a hex command that requires a
> > > checksum at the end of it?
>
> > > This will be for direct volume on a TV.
>
> > > Examples:
> > > \x08\x22\x01\x00\x00\x00\x2B  - Volume to 0
> > > \x08\x22\x01\x00\x00\x10\xC5 -  Volume to 10
> > > \x08\x22\x01\x00\x00\x64\x71 -  Volume to 100
>
> > > The sixth byte would be replaced with [sliderval].
> > > Since that number will change to where ever the slider is moved to, it
> > > is going need a different checksum for each different volume level.
> > > The checksum is two's complement and is the seventh byte as shown.
> > > Will this be possible?
>
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