Is this better or wose than the sum method ?
Maby I can do both ?

Kyrre

----- Original Message -----
From: "Philip Pemberton" <philpem@DSL.PIPEX.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, June 26, 2004 5:40 PM
Subject: Re: [PIC:] 16F88 RS232 bootloader.


> In message <1b6801c45b8c$d13a8980$fe01010a@cartman>
>           Kyrre Aalerud <kreature@C2I.NET> wrote:
>
> > What check algorithm do you guys (and girls?) suggest ?
> > It should be as small as possible, but I do have 22 words left before I
> > start on the next 32 word block...
> How about this:
>
> declare variable Checksum as byte
>
> proc checksum_init()
> {
>   Checksum = 0x00
> }
>
> proc checksum_update(byte in ByteIn)
> {
>   Checksum = Checksum XOR ByteIn
> }
>
> Basically, you XOR together all the bytes in the data block that was
> received. Compare the checksum you received with the value in the Checksum
> variable after you've scanned through all the data.
>
> Later.
> --
> Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB,
6GB,
> philpem@dsl.pipex.com              | ViewFinder, 10BaseT Ethernet,
2-slice,
> http://www.philpem.dsl.pipex.com/  | 48xCD, ARCINv6c IDE, SCSI
> ... LASER : Looking At Source Erases Retina
>
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