Intel 8 bit Checksum

[id911]

Hi all, 

Can someone please explain what I'm doing wrong to get the correct 8 bit checksum below?

I'm expecting the answer to be same as this calculator 

http://www.planetimming.com/checksum8.html

Thanks in advance

 

[[dk]]

Try this KB for calculating the two's complement. I just ran it and it got the same values as the website you posted when entering in two bytes.

[id911]

Thanks for the reply Daniel. I made few changes to meet my requirement, as per the definition of checksum. But answers are not consistent.  Please see below. 

[id911]

I think I know the problem although I don't know the solution yet. 

Labview takes my input as a ASCI (ofcourse), where as I should be feeding it in HEX.

[crossrulz · Accepted solution]

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wrote:

Labview takes my input as a ASCII (ofcourse), where as I should be feeding it in HEX.

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So you have a display issue.  Right-click on the input string and you can choose "Hex Display".  If you do this, I also recommend turning on Visible Items->Display Style.  You will probably want to do the same with the indicator.

[id911]

Problem solved. Thank you very much !

[id911]

Hi again guys, 

If I still want to asci input other than changing to HEX mode from front panel, what is it that I'm doing wrong ? VI is attached too. 

Thanks in advance.

[altenbach]

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wrote:

Hi again guys, 

If I still want to asci input other than changing to HEX mode from front panel, what is it that I'm doing wrong ? VI is attached too.  

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First of all, your 255 (or FF) diagram constant (first post) should probably be U8 representation. Notice the red coercion dot?

Second, if you cast your string to a I32, the string must be 4 bytes longs (4 characters) Is it always? Does not make a lot of sense.

The display format of a string is just cosmetic. It does not change the bits.

[id911]

Sorry, so what is your suggestion ? 

[id911]

I found the answer from one of your 2005 post @altenbach. 

Thanks champ !

Here is the link if anyone is looking.

https://forums.ni.com/t5/LabVIEW/Convert-hex-string-to-ascii/td-p/190846