Re: [avr-gcc-list] xmega128A1 + WinAvr 20081205

[Russell Shaw]

larry barello wrote:
> Is anyone successfully using WinAvr and Xmega (and fp/printf) in a 
> significant project?  I already corrected the vararg problem and have my 
> project running, but there is a rare stack corruption problem with the 
> xmega that I don’t see on the mega series (mega128 and mega1280). 
>   Interrupts and i/o change protection are the big differences between 
> the two series so that seems like a possible source of errors.
>
>
> I have five serial sources and a 1khz system timer and a multitasking 
> kernel that relies on nesting interrupts (run to completion model) and a 
> GUI.  So it is pretty busy and, as I said, works sweet on the  m128.  
> The problem is subtle.  There is no evidence of stack overrun.  Just one 
> task eventually ends up somewhere it shouldn’t be and dies.  Evidence 
> pointing to it being my problem is that it is always the same task and 
> indirectly the same routine because if I cut the routine out, the 
> problem either disappears or becomes so rare I never wait long enough…  
> The routine is a character glyph bitblit.  The evidence that it isn’t my 
> code is that I have two other bitblit routines (windows bmp, and a 
> specialized fill routine) that have the same code in their core (about a 
> dozen lines) and they don’t fail.  Failure occurs in minutes to hours 
> after starting a test screen. 
>
>
> Anyway, I am running out of ideas and starting to consider moving to the 
> mega1280.  I don’t want a big discussion, but would be interested in 
> knowing if others have success, or have seen problems.  That will help 
> me decide if I am going to pursue this more (i.e. my code issues, or 
> possible compiler issues) or drop it (chip issues).

Does the code poke any hardware? Some hardware is globally shared but
hidden such as when a 16-bit peripheral is loaded, causing strange
corruption problems.