[avr-libc-dev] Corrections of bootloader example in boot.h

[pfaff - Markus Pfaff]

Hi,

found a little problem in boot.h:

At the end of the file there's a little example (very helpful!):     


// 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 i = ADDRESS; i < ADDRESS + SPM_PAGESIZE; i += 2)
    {
        boot_page_fill(i, (i-ADDRESS) + ((i-ADDRESS+1) << 8));
    }


    // Write page.
    boot_page_write((unsigned long)ADDRESS);
    while(boot_rww_busy())
    {
        boot_rww_enable();
    }


I had to change this a little to make it work on the Mega32. If you call

  boot_rww_enable(); 
while the flash is in the programming phase this will abort programming
(see Mega32 datasheet, p. 246, description of bit 4). To prevent this I
used code like this:

              // Erase page
              boot_page_erase(((unsigned
long)FlashPageNr)*SPM_PAGESIZE);
              // Wait until the memory is erased.
              boot_spm_busy_wait();
              // Store buffer in flash page
              boot_page_write(((unsigned
long)FlashPageNr)*SPM_PAGESIZE);
              // Wait until the memory is written.
              boot_spm_busy_wait();
              // Reenable RWW-section again. We need this if we want
              // to jump back to the application after bootloading.
              boot_rww_enable();


Markus

---------------------------------------
Dipl.-Ing. Dr. Markus Pfaff
FHS-Hagenberg/HSSE
VLSI-Design
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A-4232 Hagenberg/Austria/Europe
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