Re: [avrdude-dev] special handling of 0xff in flash memory

[E. Weddington]

Brian Dean wrote:

> Hi,
>
> I've just committed a change that affects the handling of flash
> memory.  Basically, any time a file on disk is read into memory, it's
> size is reported such that 0xff padded data is ignored.  This has the
> affect of causing avrdude to only write up to the last non 0xff data
> values into the flash, ignoring the rest.  This is valid because
> writing 0xff to flash is bascially a no-op anyway.
>
> Likewise, if you instruct avrdude to dump the contents of flash to a
> file, trailing 0xff data will not be written and the file size will be
> shortened as a result.
>

I haven't looked at the code yet, or tried it, but can you explain this a
little more?

What about the special case where you have bootloader code at a high
address as well as application code in the same file? You have a big block
of valid data at the beginning, followed by a lot of "blank" memory
(0xff), followed by valid data (bootloader code) at a high address,
followed again by some blank memory (after the bootloader code). Will it
handle this?

Thanks
Eric