Pulling a pin to 12 V using 3.3V
3.3 volts > 1.4 volts.  So 3.3 volts should keep it shut off.

But for more confusion see also note 5.  The two sentences seem contradictory to me.



EDIT: Here's a pic of what I'm talking about.  Push-pull totem output is internal to the microprocessor.  You should reduce \$R_{FA}\$ by the output resistance of the totem pole, which is in the vicinity of 25 ohms.   It's in the micro's datasheet.