Subject:
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Re: Building and decoding messages
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 22 Feb 2000 01:06:49 GMT
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Viewed:
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650 times
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In article <FqAz8J.7C@lugnet.com>, "Dennis Clark" <dlc@verinet.com>
wrote:
> Hiya,
>
> Well, I'm back to my RCX message decoder project. But, I have a
> question.
> I know of the serial protocol for the individual data bytes, but I'm
> curious
> about the packet level checksum. A packet (for a message) looks like
> this:
> 55 FF 00 F7 08 <data> <~data> CS ~CS
>
> Using the message $12...
>
> If I add the bytes (mod FF) I get FF + F7 + 12, I get 08, but 09 is the
> correct checksum. Does this mean that the CS is Sum(bytes)+1?
The header of '55 ff 00' isn't counted in the checksum - just F7 + 12 =
09
Dave Baum
--
reply to: dbaum at enteract dot com
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Message has 1 Reply:
Message is in Reply To:
 | | Building and decoding messages
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| Hiya, Well, I'm back to my RCX message decoder project. But, I have a question. I know of the serial protocol for the individual data bytes, but I'm curious about the packet level checksum. A packet (for a message) looks like this: 55 FF 00 F7 08 (...) (25 years ago, 21-Feb-00, to lugnet.robotics)
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