Making a LRC calculator in Excel?

wilded · March 25th, 2005, 10:24 AM

I am trying to make a Longitudinal Redundancy Check (LRC) calculator in Excel.
I just need to get results for a single line of 6 bytes.

I.E i have 6 byte("31 01 03 00 10 08") And i want to calc the LRC for this.

31+01+03+00+10+08 = 77 ((1001101) in binary)
now i need to negate/2's compliment this and that's where i'm stuck.

Any suggestions?

wilded · March 25th, 2005, 10:31 AM

oh should have said (77) is the decimal

BrianWren · March 25th, 2005, 01:48 PM

I forget what 2âs compliment is; Can you refresh my memory? What are the steps to apply 2âs compliment to a value? (I had this in school in 1986, but have never used it since...)

wilded · March 25th, 2005, 04:47 PM

ok to apply 2's, you negate the binary number (1's become 0' and visa versa) then convert back to hex and add 1 (+1). AFAIK. ?