Re: [avr-chat] Verify on-target image

[Rogier Wolff]

On Tue, Apr 11, 2017 at 07:54:34AM +0200, Rolf Pfister wrote:
> Am 11.04.17 um 00:03 schrieb Sam Voss:
> >I was wondering if it was possible to compare the hex file that is
> >currently on the chip to hex files on the host and determine which (if
> >any) were the flashed version?
> >
> With avrdude you could do this:
> avrdude -p m8 -c avr910 -P /dev/ttyUSB0 -U flash:r:flash.hex:i
> This will write the content of the microcontroller to the file flash.hex.
> 
> But when compared the contents of flash.hex with your hex file
> usally you will get a difference even the content is the same.
> So it needs to convert to binary first to compare the two hex files.

That's not going to help.  The problem with a direct compare is that
the flash file that your compiler made only contains those bytes that
matter. The programmer leaves all other bytes at the default value of
0xff. When reading back from the chip you'll also see those "default
0xff" bytes in the hexfile. 

Just compare the hexfiles with diff, and expect to see one file
ending, and the other continuing with 0xff.... 

        Roger. 


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