Re: [lwip-users] lwip + sam7x = udef exception

[Çağlar AKYÜZ]

B B wrote:
> Hi Caglar and everyone else :)
>  
> I am using FreeRTOS v4.1.3 + lwip 1.2.0 + Rowley CrossWorks.

Hi,

As I said before, I'm using also this configuration and it is working in 
a perfect harmony for me.

>  
> Upon further investigation, it actually seems to be a stack overflow, 
> which is
> the root for my problem 
> I have increased the value for lwipTCP_STACK_SIZE from 600 to 800,
> and now the application has run straight for over an hour.

I think this stack size is well suited for most kind of operation. 
However, since you are encountering a
stack overflow issue, it is strongly probable that there is something 
wrong with the code. How do you handle ethernet
tasks. Sockets api , raw api ? If you can post your ethernet task, then 
you may find better support than me :)

>  
> I read up on the undef exception handling in the ARM archtecture 
> reference manual.
> Which says that the instruction pointed to by LR is the instruction 
> after the instruction that caused
> the exception.
> I thought as per the Atmel datasheet that the failing address would be 
> present in the MC_AASR,
> but the value in LR - offset, doesn't match the value in MC_AASR.

I think there is nothing important to be concern of this mis-alingment 
error. Since there is a fact like stack overflow
you should concentrate on it.

Can you investigate your stack when you face the undef exception. If you 
don't see 0xa5 values at the end your stack,then you
have a stack problem. If you can't debug your stack, you can try 
avaliable options in the FreeRtos code.

Kind Regards,
Caglar AKYUZ