Nvidia Jetson TX2 NX Manual page 21

POWER_EN
is a level active signal. When high, the system powers on or stays on. When low,

POWER_EN
the system powers down or stays off.
The DevKit carrier board designs latch

active. The Jetson Nano DevKit carrier board uses an SR latch with discrete logic
components was implemented to latch the
affected by any other signal other than
a button MCU controller to latch the
shutdown sequence has been initiated.
SYS_RESET*
is bidirectional. The signal is controlled by the PMIC during power-on and

SYS_RESET*
power-off. When the system is powered on,
to reset the module. This results in a full system power cycle.
The signal is asserted by the PMIC during power-on.

SYS_RESET*
is not asserted externally during the power-down sequence. When

SYS_RESET*
de-asserted, the PMIC performs a power down sequence that includes asserting
.
SYS_RESET*
SHUTDOWN_REQ*
is driven active (low) by the module if the system must be shut down, due

SHUTDOWN_REQ*
to a low power level, a thermal event, or by a GPIO on the PMIC that can be asserted under
software control to request a shutdown. The power control logic on the carrier board must
drive inactive (low) if
POWER_EN
is not driven during power-on. It is pulled up to the 5V supply, so stays

SHUTDOWN_REQ*
inactive. If the system is on and reset is driven low, the PMIC will initiate a full power cycle
and start the power-on sequence. Again,
will only go low when the system needs to shut down.
is de-asserted after

SHUTDOWN_REQ*
latch on module and is cleared when
If is asserted, the PMIC will start a system shutdown.

SHUTDOWN_REQ
de-asserted within 10 uS after
(or nearly so) in that time.
Asserting
SHUTDOWN_REQ*
high to power the system ON and low to power the system OFF can have issues.
POWER_EN
Without the SHUTDOWN_REQ* signal, there can be a logic mismatch between the module and
carrier board. If the module shuts down due to a thermal issue, and so on, then without the
signal the carrier board would not "know" that the module has shut down and
SHUTDOWN_REQ*
the carrier board may just keep
for subsequent power on attempts. The correct sequence should be to assert
signal so that carrier knows that module is shutting down so the
brought down as well. Using
must be asserted soon after.
SHUTDOWN_REQ*
NVIDIA Jetson TX2 NX
POWER_EN
POWER_EN
SHUTDOWN_REQ*
POWER_EN
SYS_RESET*
SHUTDOWN_REQ*
SHUTDOWN_REQ*
POWER_EN
POWER_EN
SHUTDOWN_REQ
is the recommended signal to initiate a power off. Just setting
high. This can cause issues including uncertainties
POWER_EN
to power the system OFF is an option, but
POWER_EN
state to ensure that the signal stays
signal and prevent it from being
. The Jetson Xavier NX DevKit uses
signal. only goes low when a
POWER_EN
can be driven by the carrier board
is asserted.
is not asserted.
goes low.
SHUTDOWN_REQ*
goes low.
is asserted. The system will be powered off
POWER_EN
Power
is
POWER_EN
SHUTDOWN_REQ*
comes from a
must be
POWER_EN
SHUTDOWN_REQ*
signal can be
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