SYS_5V rail timing on the BeagleBone

Might also be of interest to others and I wanted a second opinion before
making things more complex -

Does power from the SYS_5V rail meet timing to drive IO on the
BeagleBone/AM335x? That is -
If I use SYS_5V to drive an always enabled 3.3V LDO, will the output of the
LDO be safe to directly connect to an input GPIO.

The PMIC datasheet suggests it is not (it is the input to the 3.3V regulator
on there). Delays in the 3.3V regulator would cause the 3.3V rail to come up
later then the SYS_5V line. Checking before adding more switching and


Basically,no. You need to enable the LDO with 3.3V rail on the expansion header.