Recently, we confirmed the HW and SW shutdown sequence of Jetson Xavier NX’s EVB.
There is a question regarding the SHUTDOWN_REQ event.
For Force shutdown, we assume it should keep press power button pin(pin 240) over 10sec, and then system shutdown. However, SoC didn’t issue shutdown_req# to MCU through our measurement as below table show.
And MCU still issued POWER_EN from high to low for turning off module power. Therefore, we assume the MCU’s behavior is “MCU received power button pin(pin 240) over 10sec, and then issued the power_en(timing should be ASAP) to low”
It means MCU will not wait SOM’s shutdown_req*, and issued power_en low when MCU received power button pin(pin 240) over 10sec. Please let me know if any misunderstanding?
Not sure, HW shutdown is “keep press power button pin(pin 240) over 10sec” or not? If not, how do we make this event?
For SW shutdown, we type SUDO poweroff, and shutdown_req# goes low and MCU issued power_en. But it can’t meet T<10us criteria, the T timing is around 90us. Could you also help to check if it can be accepted?
Force shutdown: CH1: POWER_EN / CH2:SHUTDOWN_REQ#
SW shutdown: CH1: POWER_EN / CH2:SHUTDOWN_REQ#
On devkit the behavior is expected. P3509 carrier board has a DCJ unplug detection which goes directly to button MCU’s force_off pin, so regardless of shutdown_req, the debug MCU will drop power_en if DCJ voltage drops below a certain threshold. So in sudden power loss scenario button MCU will not wait for shutdown_req if it see DCJ is unplugged.
Regarding the 100us wording in datasheet, we are checking internally.
Thank you for your feedback on the sudden shutdown. However, we still have some questions on force shutdown and HW shutdown:
- For force shutdown, MCU needs to pull low power_en signal by itself once MCU’s PWR_BTN* pull low over 10sec.
- For the HW shutdown, it is also controlled by MCU? Could you let us know what scenario MCU will assert HW shutdown?
Force shutdown is devkit feature implemented by MCU thru power_en. HW shutdown is module feature no matter what trigger power_en.
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