Hello,
I try to program a
boot loader on Atmega1280.
My configuration
:
- linux
Fedora Core 7,
- avr libc
1.4.6,
- avrdude
5.3.1,
- avrgcc
4.2.0.
I use the program
in application section and there is no problem.
When I try to use
it in boot loader section, the program starts but I can't access to string in
flash.
I use
pgm_read_byte_far().
I read in file
pgmspace.h :
\note If possible, put your constant tables in the lower 64 KB and
use
pgm_read_byte_near() or pgm_read_word_near() instead
of
pgm_read_byte_far() or pgm_read_word_far() since it
is more efficient that
way, and you can still use the
upper 64K for executable code.
All functions that are
suffixed with a \c _P \e require their
arguments to be
in the lower 64 KB of the flash ROM, as they do
not use
ELPM instructions. This is normally not a big concern
as
the linker setup arranges any program space constants
declared
using the macros from this header file so they
are placed right after
the interrupt vectors, and in
front of any executable code. However,
it can
become a problem if there are too many of these constants,
or
for bootloaders on devices with more than 64 KB of
ROM.
<em>All these functions will not work in that
situation.</em>
Does that really
mean that I can't use Boot loader in Atmega1280 ?
How can I access
to string in flash ?
If someone can help.
Thanks for
answers.
Yannick
PODGORSKI.
Kuantic.
Hi,