Re: [avr-chat] Crystals (was ATmega32 @ 16MHz : fuse bits ??)

[Joerg Wunsch]

Vincent Trouilliez <address@hidden> wrote:

>> ... use a JTAG programmer you can mess with fuses to your heart's
>> content because the JTAG port has its own clock and works fine when
>> the main clock is screwed up.

Well, unless you disable the JTAG fuse, of course. ;-)

> IIRC, the latest and shiniest release of Avrdude does support JTAG
> programming ?

Yes, it does, for the JTAG ICE mkII.

> Does it also work with a cheap/DIY cable like SPI
> programming ??

Not (yet).  I tried to get JTAG ICE mkI support ready before avrdude
5.0, but didn't get it to work reliably in any way.  So far, I haven't
found the time to analyze the cause.

However, there's still avarice which has flash reprogramming support
for the mkI JTAG ICE.

> But, forgive my ignorance (I only know of avrdude), are there mature
> and usefully functional/featured open-source software that can do
> that ?

avarice + GDB

> Do they have a decently user friendly interface for setting break
> points and watching data/variables in RAM, and controlling and
> visualising code execution ?

That depends on your notion of "user-friendly" (obviously).  I for
myself always have a hard time working with AVR Studio, because I find
its user interface quite terrible.  I got quite used to GDB + Emacs as
a user-friendly interface for my purpose.  YMMV.

There are graphical frontends to GDB as well, I have no idea whether
they would fit your notion of user-friendlyness, as I've never used
them.

> And can they work with a hand made/DIY cable, or do they require
> expensive extra hardware ?

avarice works with both, the mkI and the mkII JTAG ICE (and the clones
are mkI clones usually running Atmel's original firmware).  Keep in
mind that new AVRs will probably only be supported by the mkII ICE
though, so while the cheap clones are certainly a good start, if you
restrict yourself on them, you'll also prevent yourself from using
more modern AVRs.

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

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