Electronic – Linux on ARM Cortex-M3 series


I'm new to ARM and a bit confused with all the diferent series.

I need to build a low power gateway (ethernet, wifi…), so I guess a cortex-M or cortex-R will be the good starting point.
But it didn't find any dev board with say a cortex-m3 (wich seems to be quite popular) supporting linux.

It seems possible linuxM3, so I wonder why there is no linux project around an mbed or a LPCXpresso for example ?

Can anyone point me to the dev board I seek, or explain me why "cortex m"+linux doesn't comme with more answers ?

Best Answer

Regarding the ARM Cortex-M3:

Linux requires an MMU (Memory Management Unit). The ARM Cortex-M3 does not have one. It is impossible to run the mainline Linux kernel on the ARM Cortex-M3.

However, there is a variant of the Linux kernel for MMUless processors called uCLinux.

Linux on M3 Guide

ST's Application Note on uCLinux

However, as others have noted, Linux is unlikely to be practical on the M3. It won't run without external RAM. I believe that even the largest Cortex-M3 parts only have 1MB flash, so you'll likely need extra storage too.