TPS65217C bring up

What is connected to PWR_EN?  Is that signal high or low?

floating at present --no MCU

In order for LDO1 to be on, you need to either be in SLEEP mode or ACTIVE mode.  ACTIVE mode requires PWR_EN to be high.  SLEEP mode requires PWR_EN to be low, but you can only get there from ACTIVE mode.

Please see the state diagram in the datasheet.

have power_en it to an external 1.8V LDO, am not seeing VLDO1 or any other psu activity.

If VLDO1 (or VRTC) can't turn on without PWR_EN on initially, how does the MCU get the first stage power to be able to signal the PMIC high?  What is PWR_EN high usually powered from?

My previous post was not completely thorough.

There is also a WAIT PWR_EN state during which LDO1 is on.  Once the AM335x sees LDO1, PWR_EN will automatically go high.  That state is used during wakeup from OFF.

any problem using VIO/PWR_EN as the 1.8V (if it would stay on --LDO1)?  Im still having an issue getting LDO1 to stay on.  I have both internal LDO pins showing proper voltages, but little else.  SYS voltage is around .6V  I have tied PWR_EN to VLDO1 to try to catch it on startup.  Is there an error state that would hold LDO1 off?  I've played with VBAT sense line to see if the UVLO might have something going on, but doesn't seem to make much difference.

OK, some new info:

The design is running battery free --bat charge and sense lines are bridged and connected to a 4.7uF cap.  Powering through (5.00V) into AC or USB in that configuration does not work (1.8V and all other rails do not come up).  If I bridge the 5V line to the battery cap I can get 5 V to show on SYS.  If I temporarily connect GND to the PB_IN pin that was floating on my PCB (power on button), I can get everything to power up (all rails show proper voltages LDO1 (1.8)  VCORE, MPU, 1.8, 3.3, etc..).  It seems as though I'm missing something on the AC and USB inputs --I've tied the battery sense lines to gnd, left float and this does not seem to affect the AC powered bring up (it still fails).  Now that I know that it can power all the rails in battery mode, I can discount that one of the outputs are causing the fault.  What kinds of things should I look out for regarding the AC or USB powered modes not coming up with SYS or LDO1 rails, but having internal LDO correct.  I do have LDO1 connected to the PWR_EN pin while the MCU is not populated...

"Im still having an issue getting LDO1 to stay on"  -- So LDO1 is on for a while and then it turns off?  Is it on for 5 seconds?  That could indicate that you were in WAIT PWR_EN state but had a 5s time-out.

Also, if SYS node is at 0.6V that means that the power path is turned off.  This means that you are in OFF state.

It doesnt actually show up on the DMM, but I assume based on what you said earlier, that it comes up for a few milliseconds checks for MCU response and dies.  The power path does seem to be turned off when in AC or USB state.  I'm not sure why I'm starting in off from powering up from AC or USB positive edges.  Does it sound like its faulting or not seeing the AC/USB/BAT thresholds?

~8ms ramp, seems like it should be OK

OK, have the problem figured out --my setup had an overshoot on startup when I turn on the lab supply.  I think the device was seeing the overshoot and turning on the protected input mode.  Funny thing is I don't see it over 5.8V on the scope.  Anyway, changed some caps and switch board inline to the supply and I'm doing OK now.

Thanks!