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???
08/16/07 13:33
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#143340 - a simple checksum
Responding to: ???'s previous message
I was xoring the data with the current address and summing up, like
FOR address = start TO end
  checksum = checksum + (data[address] xor address)
NEXT address

It's none better than the plain checksum but avoids the "all zeros" problem.

But, why do you think true CRC, 21 instruction cycles per byte and 23 bytes of (this is for Jürgen Christoph's implementation in the code library which is slightly better than mine), is an overkill?

JW

List of 19 messages in thread
TopicAuthorDate
Simple EEPROM checksumming            01/01/70 00:00      
   Pitfalls            01/01/70 00:00      
      a checksum out of 2 bytes?            01/01/70 00:00      
         It's an "either - or" ...            01/01/70 00:00      
            code sketch            01/01/70 00:00      
               a simple checksum            01/01/70 00:00      
                  CRC8 instead of CR32            01/01/70 00:00      
                     I am talking about CRC-16 not CRC-8            01/01/70 00:00      
                        oups            01/01/70 00:00      
   how much data?            01/01/70 00:00      
      approx 40-60 bytes            01/01/70 00:00      
      I use 2 copies and a counter for that            01/01/70 00:00      
         adding to Jan's post            01/01/70 00:00      
   Here's one method            01/01/70 00:00      
      another interesting scheme!            01/01/70 00:00      
   Try the Dallas 1-wire CRC            01/01/70 00:00      
      another good idea but...            01/01/70 00:00      
         I just meant the CRC            01/01/70 00:00      
            oups            01/01/70 00:00      

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