Re: [avr-gcc-list] Boot loaders

[Tyler Hall]

Larry,
You have to modify the linker script and add your new
section name to the list of sections that go into the
"code" memory space.

The default linker script describes a lot of object
sections and what target sections they go in, but your
new one isn't described. The linker will happily
relocate the bootloader section, but since you didn't
tell it to _also_ toss it into .text it will get
thrown away.


As for the vector table. I barely remember something
about that in the avr-libc manual. I haven't tried
relocating that myself, you might get away with adding
another switch like:
   --section-start=.vectors=0xXXXXX
where ".vector" is the name of the vector table
section...I can't remember what avr-libc sets calls
it,  look at the linker script and you'll see what I
mean.

Maybe someone else on the list could answer that
question...

Tyler

--- Larry Barello <address@hidden> wrote:
> Ok, I think I need some help.  I have a boot loader
> that I modified for GCC.  I stuck it
> in it's own section called BootLoader and modified
> the makefile to locate that section
> in high memory.  But it doesn't show up on my map
> (neither does main?) and I although I
> can see the source in Studio, when the code jump to
> it, studio looses track.  I can see
> the Program counter incrementing, but no source.
> 
> ----- near the start of my boot code ------
>  .section BootLoader,"ax",@progbits
>  .func BOOT_START
>  .global BOOT_START
> 
> BOOT_START:
> 
> ------- relevant section of the makefile -------
> LDFLAGS
> =
>
-Wl,-lm,-Map=$(<:.o=.map),--cref,-v,--section-start=BootLoader=0x1F000
> -mmcu=$(MCU)
> 
> It looks like my Boot code never made it into the
> COF file...
> 
> Any help out there?
> 
> Also, any tips for getting the C runtime interrupt
> vector table in my boot section?  Or
> do I just have to craft my own and not worry about
> the Clib version?
> 
> Cheers!
> 
> ----
> Larry Barello
> www.barello.net
> 
> 
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