[En-Nut-Discussion] Group to port to AVR32 UC3.

[Thiago A. Corrêa]

Hi Michael,

Michael Fischer wrote:
> Normaly you have only 2 breakpoints if you execute code in flash
> of an SAM7 for example. But if you can execute the code in external
> RAM, the breakpoint count is not limited. I think this is one of
> the advantage of the EIR board.

According to AVR32 Technical Reference [1] the OCD supports up to 6
breakpoints in flash and 2 data breakpoints. Hopefully that's not
restricted to the Nexus interface... as I have only the jtag mkII
right now.

Anyway, I guess I could live with 2 breakpoints as long as steping and
the data inspect function of the debugger works properly. There is
nothing worst than having to rebuild with additional debug code just
to check if a variable has the expected value.

> Specially if you want to port the assembler part (context switching) to
> the AVR32, I think a real debugger could be helpful.
>

I'm studying how to do that as I prepare my AVR32 build skeleton
(Makefiles and lua script for nutconf). AP7 seams to have some nice
automagic context switching commands, while UC3 have some quirks if
you do that inside interrupts, which we don't.

I'm having some trouble understanding the ARM and AVR context
switching ( to port to avr32). The fields of SWITCHFRAME and
ENTERFRAME are a bit cryptic to me.

[1] http://www.atmel.com/dyn/resources/prod_documents/doc32002.pdf

Kind Regards,
    Thiago A. Correa