I got my Dragon, and built a headder so it can plug into a breadboard. But cannot find how to get into debugwire mode and back...
1. Plugged in the dragon, installed the drivers automatically for Win7.
2. Launched AVR Studio, and upgraded the Dragon (which I mounted in a box to prevent any 'issues'.
3. Connect up target and try get into debug mode, chip is detected fine, and then I remember the DWEN fuse - OK, use the programmer screen to set DWEN, and cycle the target power... but that leaves me with a dead chip, so I swap another atmega168 in.
4. OK, try the demo program, build, then require about 5 mouse-clicks just to download, Download and verify, program OK.
5. Start debug,,, get cryptic error message
6. Cycle target power
7. Start debug,,, get message:
Failed to launch debug session with debugWIRE. THis could be caused by reset line circuitry or disabled debugWIRE interface. Make sure that the reset line is free before continuing. Do you want to use SPI to enable the DWEN fuse?
I had to go through above steps incorrectly a few times for some reason, the upshoot is it's working now.
1. If using debugWIRE with the Dragon, there is no need to make a special 3-pin header.
2. You do not have to start out in ISP mode, but do need to disconnect the ISP, cycle the power on the target, and then re-connect the ISP when changing into ISP or DW. If you do not disconnect the target, the fuse will not take effect.
3. I suggest only having filter caps on the target, and nothing more than 10uF so it the target will discharge.
4. AVR Studio has a totally separate deliberate step for downloading, you have to select your programmer, then verify the chip is the one you expect, then select the hex file, and then hit the "program" flash button, Flashing is not a one-click affair!
5. After a debug session, you can leave the target in DWEN mode unless you want to download again.
This story has a happy ending, I just had to share and encourage others to just perservere a little longer.