Reliable boot up on supplying power

Objective:
Need to ensure that the Jetson TX1 is turning on automatically reliably when we provide it 19 V power.

Current Setup:

  • Hardware -> Jetson TX1, which is powered on by shorting the power pins emulating a button press. The pins that we short is given below
  • https://slack-files.com/T06UBFMJP-F1LAMEU0P-2a1da79df7 is the image that shows how we short the power pins and which pins we use across our led.
  • The pins are connected across a button, which we press when we want the jetson to turn on. Ideally we would want the jetson to turn on when power is provided, but were not able to do that. hence the button.
  • The jetson is enclosed inside of a box with other electronic components
  • we have also added an led to give a hardware level feedback that the jetson has turned on. The led was connected to the pins in the picture above

Observations:

  • The jetson does not reliably turn on when we provide clean power (adaptor given with dev kit, and press the power button on the jetson itself
  • The power to the jetson is not very regulated. other components in the system sometimes send a voltage across the jetson for a very very short amount of time before jetson itself is turned on.
  • When the power is turned on, the voltage is consistent and the jetson does not turn off
  • Sometimes, the jetson turns on for a short duration and then powers off. The time is usually 5 seconds or about 16-19 seconds.
  1. If Jetson can’t be turned on by press power button, please try to press the power button twice quickly, and/or try to change C36 to 0.1uF.
  2. When you find Jetson turns off unexpected, can you check if Tj is overheat if no proper thermal solution works.
  3. If you find some power is suspicious before system is turned on, please capture the waveform to us.
  4. Power-on autostart suggestions: https://devtalk.nvidia.com/default/topic/924300/jetson-tx1/power-on-autostart/

To support auto boot after AC power loss on JTX1, The PMIC MAX77620 need a change on ACOK pin.
It was suggested that a 4.7kohm pull down and 1uf to VDD_5V0 for ACOK signal
ACOK is Pin A49 of J13 connector or Pin1 of J27 connector.
Please try to rework on Pin1 of J27(Pull down to GND with 4.7kohm and a 1 uf to VDD_5V0)

Press power button pin for ~8s will cause the PMIC force shutdown.