Hi Markus, Well I feel bad about saying this but the problem was that the legacy framework I was using to build the .hex file was giving "-j .data -j .text" option to avr-objcopy. Hence the .bootloader section was simply not present in flash.
AVR Studio uses memory models during simulation/emulation, so I was kind of blind. As you said, 0xFF instructions were getting executed until it looped back to the reset vector. One precision though... The Atmega644 _does_ support moving the whole IVT in BLS... See table 10-2 page 58 of the reference manual (2593L-AVR-02/07). So my apologies and many thanks to everyone who gave it a thought... Pat -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Markus Lampert Sent: August 23, 2007 6:01 PM To: [email protected] Subject: Re: [avr-libc-dev] Problem writing to flash - atmega644 > And once again, if I leave this routine in the .text section, the > unexpected resets suddenly disappear. That would exactly be the behaviour if you have an interrupt enabled as Joerg mentioned. The ATmega644 does not support moving the whole interrupt vector table into the bootloader section. So any interrupt (other than reset) would be serviced by whatever you have in the application section. If you just downloaded your bootloader that would be 0xFF. From experience I can tell you that is a noop (logically) and the IP gets incremented as normal. So it runs through your whole code section until it reaches something different than 0xFF which is the bootloader reset vector (typically a rjmp). Looking from the outside at the behaviour it would seem as if your processor gets reset, although no reset source will be set (as you pointed out earlier). Your best bet is going through your code and check if you enable any interrupts, or if any of your library functions do so. Markus ________________________________________________________________________ ____________ Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 _______________________________________________ AVR-libc-dev mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-libc-dev _______________________________________________ AVR-libc-dev mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-libc-dev
