Power-on Autostart

The documentation for Jetson TX1 Developer Kit Board Spec states that:

(page 30, powering up Jetson TX1 Developer Kit)
4. Plug the power adapter into an appropriately rated electrical outlet
5. They system should power on. If not, press and release the power button on the device

I observe a consistent requirement for power button press and release.

Is this a normal operation using Jetson provided power supply connected to 110 outlet in US?

If this the case, is it possible via jumper settings or board modification to remove requirement for button press?


It needs to do some modifications on carrier board to implement auto-power-on w/ adapter in.
The key point is to assert CHARGER_PRSNT when AC plug in.

On order to power the system on without a power button, a specific sequence is required between the time the VDD_IN power (5.5V-19.6V) is connected and the CHARGER_PRSNT# pin on Jetson TX1 is driven high. The CHARGER_PRSNT# pin connects to the Jetson TX1 PMIC and requires a minimum delay of 300ms from the point VDD_IN reaches its minimum level (5.5V) before it can be driven low. Three options to meet this requirement and allow Auto-Power-On are described:

  1. Microcontroller: Recommended if a microcontroller is already being used to control power-on.
  2. Supervisor IC: Using a supervisor IC and related discrete devices to meet the sequencing requirements.
  3. Discrete Circuit: Circuit using only discrete devices to meet the sequencing requirements

Hi Trumany,

Can you clarify if there are power on sequencing requirements between VDD_IN and CHARGER_PRESENT# being driven high?

I understand that CHARGER_PRESENT# is active low. Is there internal pull-up present on the PMIC or do I have to add this externally on the carrier board?

If CHARGER_PRESENT# is pulled high after VDD_IN exceeds 5.5V (via internal pull-up) then the auto power on would function if CHARGER_PRESENT# is pulled low 300ms after the 5.5V threshold is exceeded. Does this sound right? Is it okay to keep CHARGER_PRESENT# pulled low indefinitely?

I was somewhat confused by your previous explaination where you stated there was power sequence requirements for CHARGER_PRSNT# being driven high and being driven low. Can you please clarify?

Yes, the CHARGER_PRESENT# is active low w/ internal pull-up and needs 300ms low delay after VDD_IN reaches 5.5V. If keep it pulled low indefinitely, that might cause power-off sequence issue.


while googling, I found this thread. I created a small lab and have all my boards with remote access control. Unfortunately, I can’t use the Jetson TX1 because of this power on push button. If I understood correctly, there is a way to fix this. Does anyone have any information about the procedure ?

Thanks in advance.

Hello dlezcano, just to clarify: are you talking about the Jetson TX1 Developer Kit as opposed to a different board?


I’m looking to try auto start with a microcontroller. Are there any pins on the Tx1 development board that supply 5V or 3.3V before power on??

This is probably not what you are looking for, but USB ports do provide a standby 5V even with system off (this is true via either HUB or directly).

Hi ctichenor,

We are considering the same, using a microcontroller, did you find any reliable source when poweroff?


Power button (S4) is pulled up to 5V thru a 10K resistor when power off, you can use it if no much load request and pay attention it will be pulled low when pressing power button.

Hi Trumany,

actually most of the boards I have will auto poweron when plugged in. This behavior is usually configurable via a switch or a via the place the board is plugged (eg. powered through usb or DC).

So, IIUC, the solution would be to solder directly the output of my relay to the S4 and close it one second (> 300ms) to emulate a button-press, is that correct ?

Is there any other way to do that ? Eg, a configuration in the firmware ?

Anyway, if it is not possible I will deal with power input + delay + J6/S4 signal.

Hi dlezcano,

Seems you are just looking for remote controlled power on, right?
If so, yes, you can simply use a relay to remote control power button to power on. I don’t think firmware can help on this as it’s a hardware action before system on.

I think ‘remote controlled power on’ is the only option, as the Jetson TX1 dev board seems to have no other means to turning it on other than pressing (or simulating the press of) the power button once Vdd is appropriate.

I suppose a question not entirely answered: On the Jetson TX1, is there any source for power from the board (A breakout for the DC jack voltage for example) that a microcontroller or alternative circuit may be powered from so it can automatically ‘press’ the button?

Tapping into the pulled-up 5V via power-button was a silly suggestion :) once ‘pressed’, the circuit (or micro) will reset and repeat!

If there is no source for power when the board is off, then the solution is obvious: Power the ‘button press’ circuit externally. I just want to make sure that is the only way.


There is a 10k PU on the 5V of S4, that’s why microcontroller can use it and will not cause power off. This can be done by some rework in module, not to connect microcontroller to S4 directly. And external power supply surely can work on this too, but i think user usaarizona is asking for a on-board power source of dev kit.

You are suggesting that a micro-controller may be powered from a 5V source even though there is a pull-up of 10K-Ohm in between (on S4, which is also jumper J6).

I suppose in my world of thought, this solution is not feasible due to (using ohms law) the voltage drop you would have from the load of a micro controller would not leave you with any voltage for booting your micro. I have tested with a micro which needs 5V (4.5V min) to power up, and it did not work. Measure the voltage before connecting micro and you have 5.0V. Measure after connecting micro (directly to VCC pin) and voltage is dropped to 1.5V. Bad solution.

Not to mention: Pressing the button (or even simulating the press of a button) WILL turn off your micro, because you are shorting it’s high-impedance 5V connection to GND!

This is just not feasible. Thus the only solution for auto-powering the NVidia TX1 dev kit, is by providing power for the external circuity OUTSIDE of the jetson tx1 development ECU (unless proven otherwise that there is a reliable breakout of power).

I think you misunderstand what i meant. I suggest to rework on module side to connect micro to 5V source itself directly, not to power key (which goes to 5V source thru a 10K PU). This 5V supply is always on after DC plug in, if the load of micro is not too much, it can be used and will not be pulled low in any case.

You were not so clear (and still are not clear): How would one tap into this 5Volt source using the Jetson TX1 carrier board? Where is there such a connection available for “re-work”? Because this would be what people are looking for.

I already said this rework is on module side which I think is clear enough. And because the schematic/layout of module is not public, I can not share the detail points, but it is not difficult to find this 5V source on module board. Hope this can help you.

I have fixed the Tx1 board in an aluminium enclosure with ventilation and cut-outs for the connectors.
I have made a provision external push button to turn ON the board.
Can you tell me where should I connect button (two wires) on the board?
Can PNL PWR “J6” can be used for this purpose?

Yes, J6 is connected to power button.