Re: [avrdude-dev] xmega status

[Paul Thomas]

On Tue, Oct 6, 2009 at 11:29 AM, Zoltan Laday <address@hidden> wrote:
> Paul,
>
> On 10/6/09 7:20 PM, Paul Thomas wrote:
>>
>> Hello,
>>
>> I'm new to the list, but I wanted to ask a few questions while my
>> hardware design is still on paper.
>>
>> First, it looks like from both the mailing list and the source tree
>> that programming xmega parts using the jtagmkII via the JTAG interface
>> is supported. Is that right? Are there any problems/limitations? I saw
>> one post that said the fuse programming didn't work?
>>
>>
>
> Yes, xmega parts are supported using JTAGICEmkII via the JTAG interface.
> The xmega support is pretty usable, but not perfect.
> I added most of the xmega support. Read functions were tested quite
> thoroughly and found to be
> working. Memory write functions are also ok. Fuse read is ok, but there can
> be problems
> writing them. One other known limitation is that the target is not reset
> after programming
> finishes (so, eg. it starts to execute the newly downloaded code only after
> a manual reset).
> (This works in AVRStudio in Windows.) PDI is not supported.
>>
>> Second, are any other programmers supported? It would be nice to use
>> something like the USBtinyISP or the AVRISP2 (low cost). I saw this
>> post (http://blog.frankvh.com/2009/09/22/avr-xmega-and-avrisp-mk2/)
>> that says the AVRISP2 is supported by the latest avr studio. From the
>> description it looks like the old ISP was 3-wire SPI whereas the xmega
>> is only 2-wire (shared data). In the source tree I saw just a few
>> references to the XMEGA PDI interface, but nothing to suggest it was
>> supported. Also on the mailing list a couple of people asked about
>> using the PDI interface, and it looked like it was undocumented from
>> Atmel and thus unsupported by avrdude? Do I have this right?
>>
>>
>
> AFAIK, there is no support for the xmega parts on the AVRISPmkII.
> As far as the physical PDI interface is concerned, it is not available on
> the AVRISPmkII only, but
> it is on the JTAGICEmkII, too.
> PDI interface is documented in Atmel literature, so the method of
> communication between the
> programming tool and the target MCU is known.
> As far as avrdude PDI support is concerned, however, this is not relevant.
> The real question is if the protocol between the host machine (Mac or PC,
> serial or USB) and the programming
> tool is supported by the avrdude code. This protocol is different on the
> JTAGICEmkII and the AVRISPmkII.
> These protocols are documented in Atmel literature, too.
> The catch, however, is that this documentation is outdated. I do not know
> too much about the AVRISPmkII
> documentation, but I had to analyze the protocol thoroughly for the
> JTAGICEmkII when I was
> adding xmega support. The situation is that the JTAGICEmkII uses
> undocumented extensions of the
> protocol when dealing with new MCU families like the xmega and the AVR32.
> I could add xmega support only by reverse engineering the protocol
> extensions.
> Reverse engineering means that the serial line or the USB needs to be
> sniffed while programming
> is performed with the factory supported AVRStudio tool in Windows and you
> should make
> your best guesses what the undocumented messages do. This situation makes
> it difficult to eg. find the culprit of such issues that the target is not
> reset after programming.
> In the case of the xmega, about 20% of the messages are undocumented.
> In the case of the AVR32, it is the other way around, about 80% of the
> messages are not documented. This makes AVR32 support very hard or even
> impossible.
> As far as PDI support for xmega parts on JTAGICEmkII is concerned, is
> undocumented,
> but it does not seem to be particularly difficult to add support for it. It
> will, however,
> have a command line interface implication, as the physical interface
> selector (JTAG or PDI)
> should be added there.
>
> Regards,
>
> Zoltan
>>
>> Finally, what support is there for using a bootloader with avrdude on
>> the xmega parts? Looking at this site
>> (http://pramode.net/2008/01/23/avr-atmega16-bootloader-experiments/)
>> it looks like the butterfly programming type is just talking to a
>> bootloader. Has anyone tried something similar with the XMEGAs? Is the
>> butterfly "type" what I should be investigating?
>>
>> thanks,
>> Paul
>>
>>
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>>
>
>

Zoltan,

Thanks for the detailed update. I look forward to using the
JTAGICEmkII with the XMEGA.

Did anyone have any insights into using avrdude with a bootloader
through a standard serial port?

thanks,
Paul