ARM CM3 printf() problem

[Freddie Chopin]

General advice regarding printf():

1. Make sure that your stack is double-word aligned - that is 8-bytes

2. Make sure you have A LOT of stack, printf can use up to 1kB of stack 
- really! If you don't plan to use floating point you can cut that down 
by using integer-only version iprintf().

Your problem is caused by wrong linking - notice that the problematic 
instruction is "blx <even-address>", so it tries to switch to ARM mode, 
which does not exist for Cortex-M3. First of all you need to use gcc (or 
g++) for linking, not ld directly - this way it's easier to deal with 
multilib. Second thing is that you need to have proper multilibs, 
compiled for cortex-m3 in thumb mode...

4\/3!!