[avrdude-dev] [bug #30061] stk500 skips writing blocks of 0xff, even if the part/page wasn't erased

[Joerg Wunsch]

Follow-up Comment #1, bug #30061 (project avrdude):

I'm afraid you have to elaborate a little more:

This is standard EPROM behaviour, you can only write a '1'
bit by erasing the memory.  A normal write cycle can only
write a '0' bit, or it does not change the cell if it is
trying to write a '1' bit.  Thus, writing pages that consist
of only 0xFF is essentially a no-op, and can always be
skipped.  Obviously, if the page does have prior contents,
and the file has 0xFF, without erasing it, this will result
in a verification error if verification is enabled.

For the STK500 algorithm, there is no option to page erase
the memory, only a device erase is supported.  With the
current AVR architecture, only bootloaders could perform a
page erase, but as there is no corresponding STK500 command,
AVRDUDE has no means to tell a bootloader that a page erase
is required.

    _______________________________________________________

Reply to this item at:

  <http://savannah.nongnu.org/bugs/?30061>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.nongnu.org/