We have been using a custom carrier board with a TX2 Module configured for auto power on. Recently we switched over to a TX2 4GB module and we have run into an issue during a module power cycle.
We wait one second after we see the Carrier board power on signal fall to O volts before pulling power from the VIN pins.
We then wait two seconds once we disable the VIN power supply then we turn the supply back on to complete the restart.
This sequence works every time with the 8GB module, but the Jetson 4GB does not come back once we reapply power. We have to wait 4 seconds from pulling power to reapplying power to consistently get a proper boot up from the 4GB module. It appears the PMIC isn’t fully turning off (measuring the OTG ID pin)
My questions
1.) Is there a proper way / official timing in terms of a reboot or is this outside of the normal Jetson use case scenario ( Pulling VIN and applying VIN in a sub 4 second time window)
2.) Are we suppose to turn the PMIC off in software or by pulling on a pin?
As below screenshot showing, there is a workaround on carrier board to add delay on ACOK, can you please try it on your board?
However, the circuit has two assumption on customer side:
CVM pin A36 USB0_OTG_ID is not used by carrier board other function
a. If USB0_OTG_ID is used: connect R231 to CVM VDD_IN power, and stuff R232 to divide the voltage based on customer’s power supply voltage.
There is a always on 5V_AO power. Always on means it power up before CVM power. 3V3_AO should be OK for this function too.
a. If not available, using an LDO to get 5V_AO is an option
This is great news, this is same conclusion we came to based on reading other forum posts.
We already had a similar circuit implemented to allow the Carrier_PWR_ON to drive the state of our system, so adjusting the use case to be with USB0_OTG_ID should work well.
