I'm trying to power everything off my 3V battery pack including the mega48 sitting on the STK500.
To do so, I disconnect the VTARGET jumper on the STK500 and put 3V from my battery pack on the VTG pin of one of the port headers. I also attach the negative side of the battery pack to one of the GND pins of the STK500.
In this configuration, the circuit doesn't turn on.
If I plug in the regular power supply to the STK500 (but change nothing else - VTARGET is still disconnected) it all works.
I'm not sure why I have to power the STK500 control chips in order to get the mega48 to run. The mega48 is using its internal oscillator.
Anyone know what I'm missing?