Re: [avrdude-dev] JTAG ICE3 + XMEGA32A4U = works! Now the DFU..

[Joerg Wunsch]

As "Ing. Daniel Rozsnyó" wrote:

> But no mention about what the VTG is (input or output, what voltage
> it accepts or supplies).

As already with the JTAGICEmkII, VTG is normally called "VTREF".  It's
the reference supply voltage from the target, which is used for the
levelshifters, so the ICE talks at the correct voltage level with the
target, independent from the ICEs internal Vcc.  (As such, the level
shifters draw several 100 µA from this pin — just to keep this in mind
for battery-powered applications.)

> Yes, it just says to flip that bit (in text, not giving exact way
> how to do it), so in x32a4u case that is:
> 
> -U fuse2:w:0xBF:m
> 
> I can read that back too.

OK.

> Is it possible to detect, why the bootloader fails? E.g. see from
> dis-assembly if it really checks for PC3 being low ?

I think the Xmega DFU bootloader is available as source code, so it
should be possible to have a look at what they are doing.

-- 
cheers, Joerg               .-.-.   --... ...--   -.. .  DL8DTL

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