Re: [avr-gcc-list] ATmega64 boot code blues

[Theodore A. Roth]

On Wed, 30 Jun 2004, Richard Ziemerink wrote:

> Hi,
>
> I am trying to write a bootloader for the ATmega64 using avrgcc.  As a
> small test to see if I could change the program memory I tried out the
> following code:
> [code]
>
> #include <avr/interrupt.h>
> #include <avr/boot.h>
> #include <avr/io.h>
>
> int main(void)
> {
>  #define ADDRESS     0x1000UL
>
>    // debug pin
>     DDRE =  0xff;
>     PORTE = 0xff;
>
>  // Erase page.
>     boot_page_erase((unsigned long)ADDRESS);
>     while(boot_rww_busy())
>     {
>         boot_rww_enable();
>     }
>
>     // Write data to buffer a word at a time. Note incrementing address
>     // by 2. SPM_PAGESIZE is defined in the microprocessor IO header
> file.
>     for(unsigned long n = 0; n < SPM_PAGESIZE; n += 2)
>     {
>         boot_page_fill(ADDRESS + n, n);
>     }
>
>     // Write page.
>     boot_page_write((unsigned long)ADDRESS);
>     while(boot_rww_busy())
>     {
>         boot_rww_enable();
>     }
>
>  for(;;)
>  {
>     PORTE  ^= 0xff;
>  }
>
>  return 0;
> }[/code]
>
> The code is located at address 0x7C00, and the following values have
> been set
>
> BOOTSZ = 01
> BOOTST =  0
> No lock bits have been set.
>
> I have verfied that the program  is running by looking at the toggling
> of PORTE.
>
> I would expect the program memory to change, but when I read the memory
> back via the ISP port all memory values except the values where  the
> booloader is located  equals 0xff..
>
> Could anybody please point out what I am doing wrong here?  I  have run
> out of ideas and would appreciate some input.

You might be interested in this:

  http://lists.gnu.org/archive/html/avr-libc-dev/2004-02/msg00053.html

There's a link in that message to another one that might be related to
you problem.

You might also want to have a look at the boot.h file in cvs head. The
example there has been updated.

---
Ted Roth
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