AVR-Chat

Hi 
  you can use a pull up ressistor (internal pul ups can be used) on the slave front for each input pin of spi (MOSI,SCK,SS) and a diode which anode is connected to slave pin and the cathode is connected to the corresponding pin of master.
   
  I dont have any idea about MISO pin.

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.

It appears we could isolate them with optoisolators. But is there a
better/cheaper/smaller way?

Jim



                         

       
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