[AVaRICE-user] AVaRICE with AVRDragon and AtMEGA8u2, debugWire

[Brian <bh...@ch...>]

Hello,

I'm trying desperately to cut all ties with the Windows desktop, and I'm 
down to getting a working debugging environment set up for my projects 
based around the AtMEGAXXU2 line of processors, which AVaRICE 2.13 does 
not appear to directly support.

I found one thread on AVRFreaks[1] from 2010 where some fellow describes 
almost exactly the problem I'm having, and his avarice command used 
"--part atmega48" -- he does not describe how he came to select atmega48 
as the device to force.  More importantly, there is not a single 
response to that thread! :-(  So there's no help to be had.

Anyway, it boils down to this:  AVaRICE will start and seem happy, 
avr-gdb will connect to it and seem happy, but once I actually start 
execution (by issuing "continue" command) AVaRICE very quickly starts to 
complain about receive timeouts:

    got asynchronous event: 0xf7
    recv: timeout

    command[0x00, 7]: 00
    recv: 0x1b
    recv: 0xff
    recv: 0xff
    recv: 0x01
    recv: 0x00
    recv: 0x00
    recv: 0x00
    recv: 0x0e
    sDATA: reading 1 bytes
    read:  f7
    recv: 0xc6
    recv: 0x79
    CRC OK
    Got message seqno 65535 (command_sequence == 16)

This sequence of messages is emitted repeatedly, with the values in the 
square brackets of "command[0x00, 7]: 00" changing/incrementing until 
eventually this message arrives:

    got asynchronous event: 0xf7
    recv: timeout
    terminate called after throwing an instance of 'jtag_exception'
       what():  JTAG communication failed
    Aborted

..at which point AVaRICE exits and of course avr-gdb tells me the remote 
connection is closed.

So...is this something to do with telling AVaRICE it's an atmega48 when 
it's really an atmega8u2?  Suffice it to mention that using Atmel Studio 
under Windows works flawlessly.

AVaRICE v 2.13, built from source
avr-gdb 7.7.1
Debian Jessie x64
AVRDragon firmware revision 7.39

Thanks in advance for any help!

Regards,
-Brian