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???
11/03/06 13:00
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 		 #127314 - timestamp, serial number, neutral 16 bit checksum
Responding to: ???'s previous message
I like to use a timestamp (__DATE__ and __TIME__ near the end of code memory) and two 'neutral' 16 bit checksums (one at 0x0ffe, the other at 0xfffe).

'neutral' in the sense of -Big_Endian_Checksum_Negative or -Little_Endian_Checksum_Negative of the srecord.sf.net package. (XOR could probably be used too)

Using checksums which add up to zero allows me to check:
sum(0x0000..0x0fff) = 0 (bootloader)
sum(0x1000..0xffff) = 0 (application)
sum(0x0000..0xffff) = 0 (bootloader and application)

Also I can serialize the device by inserting a 4 byte serial number (+2 bytes special padding) into a reserved 6 byte field within the bootloader section (without spoiling the checksum).

List of 26 messages in thread
TopicAuthorDate
Global Checksum            01/01/70 00:00      
   Checksum of what?            01/01/70 00:00      
      Rom Contents            01/01/70 00:00      
         why checksum???            01/01/70 00:00      
            The OP intended to use CRC-32...            01/01/70 00:00      
            ... but it's a good point otherwise...            01/01/70 00:00      
               timestamp vs crc            01/01/70 00:00      
                  timestamp, serial number, neutral 16 bit checksum            01/01/70 00:00      
                  who said 'automatic' and yes I have            01/01/70 00:00      
                     You didn't, Jan did            01/01/70 00:00      
   A bit of a logical fallasy            01/01/70 00:00      
      not at all... depends on application...            01/01/70 00:00      
      Statistics            01/01/70 00:00      
         ferrite beads            01/01/70 00:00      
            \"legitimate\" uses of checksum            01/01/70 00:00      
               I have seen NO catches by a checksum            01/01/70 00:00      
                  it's not just the matter of "kitchenware"...            01/01/70 00:00      
                     One thing that should not be handled by checksummi            01/01/70 00:00      
                        blah blah            01/01/70 00:00      
                        That's not how I remember it ...            01/01/70 00:00      
                           that was me            01/01/70 00:00      
                  I\'ve got a box that contains a few ...            01/01/70 00:00      
            links to CRC            01/01/70 00:00      
               I still say that crc's and checksums only work            01/01/70 00:00      
                  Most            01/01/70 00:00      
      I'd like to learn more            01/01/70 00:00      

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