Re: [avrdude-dev] xmega PDI support for stk500/avrispmkII/jtagmkII?

[Joerg Wunsch]

As Galen Seitz wrote:

> What is the status of xmega PDI programming and debugging support
> using the stk500/avrispmkII/jtagmkII?  Assuming the PDI protocol
> documentation is not currently available, has anyone gotten feedback
> from Atmel as to when it might be released?

The low-level PDI protocol documentation itself is part of the Xmega
datasheets, and programming is supposed to be documented as well.

As nobody (so far) came up to roll their own PDI hardware, what's more
important to us is the protocol documentation for the Atmel-delivered
tools, about how to talk to Xmega/PDI devices there.  So far, the only
available documentation here is the STK600 protocol document.  This
has been the base of the current AVRDUDE implementation.

Supposedly, the AVRISPmkII uses the same protocol in that respect, so
it automatically benefits from the STK600 implementation.  (It appears
to be currently broken due to some parameter issues in avrdude.conf
though.)

However, there is zero documentation about how to debug Xmega devices.
AVaRICE made some effort to support it, using the JTAG implementation
through the normal JTAG ICE mkII in a similar way as it used to work
for classic AVRs.  This works to some degree, but fails at the point
where the Xmegas differ from the classical AVRs -- and they differ in
a lot of things, most notably in their entire breakpoint handling.

Also, there is exactly zero documentation about how to debug using an
STK600 or JTAG ICE mkII on top of PDI.

> The avrdude 5.8 documentation implies that PDI programming is
> possible using the stk600.  How does the stk600 differ from the
> stk500 with regards to programming?

The STK500 simply cannot handle PDI at all.  As its firmware is filled
up to about 99 %, there is not even a remote chance someone could add
PDI support to it, even if the hardware were capable of handling PDI
(which is about as questionable as well).

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

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