output low or high impedance only

[Ttelmah]

output_float.
It basically turns the pin into an input, without reading the data, leaving it in a high impedance state.

Best Wishes

[david9000]

bingo. Thanks

[david9000]

I know it's high voltage for an io pin, but when I input 9V from my battery, I can see 25mA is flowing into the high Z pin. Why?

I don't see any current flow when I input 5V from the regulator into the HIgh Z pin which is expected and good.

[dyeatman]

You are seeing junction breakdown because you are greatly exceeeding the chip maximum ratings (5.5VDC).. I'm surprised you didn't blow the chip.

From the manufacturer manual.

# Input voltage: Vin
Maximum voltage that may be applied to input pins.
This voltage is determined by the punch-through breakdown voltage of the input transistors or the breakdown voltage of input diodes, and therefore voltage exceeding this rating may destroy these transistors or diodes.