Big endian and Little endian ?

asterix · ‎2008-01-09

Posted on January 09, 2008 at 18:05

asterix · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Hi Folks,

I am tearing my hair out on this one and hoping someone can help :

is STM32 ( Cortex-M3) Little or Big endian and how we can change it at both processor level and in keil or IAR compiler options ? :-?

Thanks , Magigimix

edware · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Hi Magigimix,

Here's a quote from the Arm M3 Cortex Technical Reference Manual:

Quote:

The processor can access data words in memory in little-endian format or big-endian format. It always accesses code in little-endian format.

Note

Little-endian is the default memory format for ARM processors.

...

The processor contains a configuration pin, BIGEND, that enables you to select either the little-endian or BE-8 big-endian format. This configuration pin is sampled on reset.

You cannot change endianness when out of reset.

I hope you still have some hair left!

Regards

edware

sjo · ‎2011-05-17

Posted on May 17, 2011 at 12:20

No you cannot change the endianess, it is little endian only.

The BIGEND is an internal setting to the cortex die.

Cheers

Spen

asterix · ‎2011-05-17

Posted on May 17, 2011 at 12:20

Dear edware,

Thanks so much , I still have some :) last night.

back to your answer and to conclude : I can change at reset the data endianess only, but how ? I can not see any pin called BIGEND. Thx again.

kind regards, Magigimix

HDaji.1 · ‎2023-11-20

"some hair left" is the reason I thumbed it up. :D