AVR-Chat

That argues for an external pullup on the SS line to make sure it is  
not asserted during reset.

Jim Wagner
Oregon Research Electronics

On Sep 2, 2010, at 9:20 PM, Clark Martin wrote:

>
> On Sep 2, 2010, at 9:02 PM, Jim Wagner wrote:
>
> > Most of the ATtinys that that have debugging have DebugWire which  
> uses
> > the reset pin, only. Check the processor you are interested in for
> > DebugWire. If it does not have it, then no debugging on that chip.
> >
> > You might need a way to isolate the other lines during operation if
> > you need to actively use one of those lines. I seem to recall folks
> > using a series resistor between the programming connector and the
> > micro, in that case.
>
> On the ATMegas I use a 1K ohm resistor between the shift register  
> and the MISO pin on the chip (and the pin to the programmer). AFAIK  
> the Tinys should work the same way. None of the other pins need any  
> isolation since only the MISO is an input to the chip. You do have  
> to watch out for the serial stream affecting the SPI device(s) but  
> that isn't likely since SS shouldn't be driven low (although it  
> might float low since it will be hi impedance until the SPI is  
> initialized).
>
> >
> > Jim
> >
> > On Sep 2, 2010, at 8:48 PM, Philippe Habib wrote:
> >
> >> I'm considering an ATTiny part but I'm not totally clear on the
> >> programming and if source level debug is supported. My reason for  
> the
> >> ATTiny is the physical size I can have is very constrained.
> >>
> >> The programming data line is also the I2C data line. Does that mean
> >> no I2C if I want in circuit programming?
> >>
> >> Is source level debugging possible on the part?
> >>
> >> I'm guessing that I can't have source level debug and I2C at the  
> same
> >> time since they share a pin.
>
> Clark Martin
> Redwood City, CA, USA
> Macintosh / Internet Consulting
>
> "I'm a designated driver on the Information Super Highway"
>
>
> 



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