On many MCUs, pin-states default to tri-stated (a.k.a. analog inputs) when the MCU resets so as to not affect the circuits they are connected to until software configures the pins. The tri-stated pins also allow the HW designer to choose the pull state of each pin on a case-by-case basis in function of the underlying circuitry.
However, there are some MCUs (and SoCs) that default their pins to instead activate an internal pull-up/down. For example, the LPC845 defaults all pins to pull-ups coming out of reset.
Is there a reason defaulting pins to pull-up/down is preferable to tri-stated (other than the possible incremental power savings when coming out of a reset, or the marginal BOM cost savings)?
If anything, I rarely find that pins should be pulled-up coming out of reset (I typically need to pull them down, if at all).