Re: [avr-chat] avr-gdb, assembly, and JTAG

[Joerg Wunsch]

As Graham Davies wrote:

> >Why are you throwing debugWIRE into the debate?

> The OP stated that 
> to turn debugWIRE on and off under her Linux tool set, it is necessary to 
> rewire to high voltage programming mode.

Sorry, I missed that.  Seems I stopped reading the original posting
before that...  He didn't right away state it but he suspected it.

>  I don't know if that's true, but 
> you certainly don't have to do that with AVR Studio.

Since the tools hardware involved is the same, the possibilities are
also the same, regardless of the operating system.  Sure, there might
be situations where you can shoot into your foot with debugWIRE
(e.g. if you power-off the SPI in your firmware, the chip is rendered
inoperable until you clear the DWEN fuse and/or chip-erase it using HV
programming), but in general, there are no different limitations of
debugWIRE whether you run it on Windows, Linux, FreeBSD, or Solaris.

Similarly, if you disable both the JTAGEN and the SPEN fuse through
JTAG on a JTAG-capable device, you can no longer program/debug it,
and have to HV reprogram it.

However, the OP was under the wrong assumption anyway that the
ATmega8515 shipping with the STK500 would offer debugWIRE; in fact, it
doesn't.  So as the other AVR shipping with the kit is an ATmega16,
that's certainly a good choice for experimenting.

-- 
cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)