CRC question

[jim s]

dwight elvey wrote:
>
>
> Hi
>  It is most likely a simple checksum and not a crc. Still, making a crc
> come out to zero is not hard. It is about the same as a checksum resulting in zero.
> If it was doing a 16 bit crc, it would need 2 bytes to be the check bits.
>  Still, most ROM checks that I've seen are simple checksums.
> Dwight
>   
Checksums have a problem when used to check prom space in that a common 
error in function can just
misorder the bytes or location of the eproms in memory space, and a 
checksum won't catch that.

CRC's can be constructed which will only work well if the bytes are in 
the correct order thru the entire
space.

Jim