Here I come again back to the best AVR forum to ask for some experience.
I'm planning to do some I2C communications, single master, multiple slaves. The idea is to have a logging station, so each slave is nothing but a simple sensor (temperature or whatever).
This is the question: is it neccesary to power on every slave before starting the master?
It's obvious that the master won't be able to find them otherwise, but what I mean is..
1) Do the avr pins have high-impedance when the avr is off? That should be so in order for the pullups (at the master side for instance) to keep the lines high. (I should test this, I haven't yet)
2) if a device is powering on and other two are communicating, will it be able to turn on silently in order to avoid interference on the lines?
Maybe I should try these first in practice, but I wanted to know other's experience with this.
Thanks a lot!