10 Nov
2007
10 Nov
'07
1:39 p.m.
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