ATmega128 has no support for the BREAK instruction

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Hi there,

Reading the help of the mkII I see at supported devices a note telling me "Note that ATmega128 has no support for the BREAK instruction"

does anybody know what does it means?

thanks.

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

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It means the JTAGICE doesn't have the option of setting "software breakpoints" with that chip. Only "hardware breakpoints" are available.

It shouldn't affect your day-to-day usage of the ATmega128, except that there'll be a limit to the number of breakpoints which AVR Studio will allow you to enforce simultaneously.

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Ok, ifmorrison thank you very much.

Michael.

User of:
IAR Embedded Workbench C/C++ Compiler
Altium Designer

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Actually some might even call it an advantage. When soft breaks are used it involves the debugger erasing/reprogramming the code flash to replace an instruction with a BREAK while if only h/w breakpoints within the AVR's separate OCD block are used that won't be necessary - so you won't "wear out" the flash in a part used heavily for debugging.

Cliff

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According to the Trondheim folks, they've never seen any real sign of
"wear out" caused by software breakpoints. However, there's at least
the disadvantage that rewriting an entire page of flash takes much more
time than the JTAG hardware breakpoint handling. But as long as you
restrict yourself to at most 3 breakpoints (the fourth one will always
be reserved for single-stepping), no software breakpoints will ever be
needed for JTAG.

Things are completely different for debugWire, which can *only* do
software breakpoints. I'm rather impressed how fast it "feels" anyway.

Jörg Wunsch

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