AVR-Chat

Hi Jim,

On 9/2/07, wd0e <jim@coloradosatellite.com> wrote:
> We have a pair of ATMEGA128s talking to each other using SPI.  The
> slave is not always powered on.  The problem is when Vcc to the slave
> is off it gets partially powered by the SPI lines.

Configure the output SPi lines as GPIO and set them up as outputs
which get driven to ground. This should eliminate and leakage current
via that means. Input lines need to not have any pullups on them.

Have an input signal from the other processor which indicates when
it's on and when its not. You can then reconfigure the appropriate
lines when the other processor powered on versus not powered on.


-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/