[avr-gcc-list] Re: [PATCH] avarice: JTAG ICE: Cannot synchonise

[Shaun Jackman]

On 7/6/07, Joerg Wunsch <address@hidden> wrote:
> > I should mention I was using
> > debugWire to communicate with a AT90PWM3B.
>
> I don't have an AT90PWM3B (only the older AT90PWM3), but I've
> seen similar problems on other debugWire devices as well.

I initially suspected the new AVR Dragon I was using, but I pulled out
my old AVR ICE mkII, and it exhibits similar problems when using
debugWire. It's more likely that debugWire is the problem than the
programmer.

I haven't ruled out the possibility of a communication problem
specific to my board. At least there's only one communication line to
worry about with debugWire.

I've read about problems with debugWire when there's a capacitor on
the nRESET line. I don't have a cap, but I do have a voltage
regulator/power-on reset controller, MIC2951, with an open-collector
output on the nRESET line along with a 10k pull-up resistor. Perhaps
the resistor is too small.

Cheers,
Shaun