Simple voltage level shifter questions...

[alank2]

I am trying to interface a single bidirectional data pin cheaply and with as little components as possible.

On each side I have an AVR, so I can use the pullup on its GPIO pin if that helps/eliminates any external components.

One AVR will be running 5V from USB, the other AVR might be 2.5V-5V.

The thing is that I only want a 2 pin connection to the 2.5V-5V AVR.  Ground and data.  I found this BSS138 shifter, but it shows LV coming from the lower voltage device which would be 3 pins which I don't want.



Any ideas?

[alank2]

I should add that I plan on having each AVR switch between input with pullup enabled OR output ground.

[alank2]

Any ideas or suggestions?