[En-Nut-Discussion] IP Checksum calculation broken. Reenabled old algorithm for the meantime.

Ulrich Prinz ulrich.prinz at googlemail.com
Thu Jul 5 14:26:54 CEST 2012

> My first intention is to provide a highly portable, generic routine to get new targets up and running fast.

As we have only 8bit and 32bit targets,we only need optimized
functions for these two. They can be compiled in depending on the
compiler switch for the architecture width.
> The second intention is to have a "Plan B" version available in case the architecture specific version fails for some reason, e.g. after upgrading the compiler.

Hmm. For testing ethernet you do not need to have CRC. And if you like
to provide a complete stack for your cpu, you need to provide CRC, if
it is possible (enough power or HW).

For STM32 I have no issues with the HW CRC calculator. I use it with
and without DMA for my CAN system and for image verification in the
bootloader. But I think I am always on word boundary.
I am not sure about the memory impact if going from 1 to 4 but I
consider it to be the safest. If you need to safe memory you could try

So why not setting it to 4 and let's fix all the other errors, Then we
could investigate again with the 2.


More information about the En-Nut-Discussion mailing list