Hi,
I have a question about the TX2 NX power down sequence.
It is stated that POWER_EN can be used to turn off the system, but does it mean that if I set POWER_EN low before SHUTDOWN_REQ is asserted, SHUTDOWN_REQ will be asserted automatically?
In the red line at the top below, it is stated that SHUTDOW_REQ is deasserted after POWER_EN goes Low, so please tell me about the behavior when POWER_EN goes Low first.
Best Regards,
UNA
hello UNA_H,
may I know what’s your actual use-case?
as it state in the Jetson TX2 NX Product Design Guide,
the correct sequence should be to assert SHUTDOWN_REQ* signal so that carrier knows that module is shutting down, so the POWER_EN signal can be brought down as well. for the Jetson Xavier NX Developer Kits, POWER_EN only goes low when a shutdown sequence has been initiated.
Hi JerryChang,
may I know what’s your actual use-case?
As mentioned above, I am assuming the case where POWER_EN is Low before SHUTDOWN_REQ is asserted.
Since the Jetson TX2 NX Product Design Guide states that POWER_EN can be used to turn off the system, please show the behavior of SHUTDOWN_REQ in that case.
Best Regards,
UNA
hello UNA_H,
those figure5-5 and figure5-6 power down sequence has indicate the case.
For figure5-5 and figure5-6, SHUTDOWN_REQ is asserted first!
What I want to know is the case when POWER_EN is Low before SHUTDOWN_REQ is asserted.
Please refer to latest doc in DLC. SHUTDOWN_REQ is used by module to request carrier board to power off. POWER_EN is for module on/off. POWER_EN is always before SHUTDOWN_REQ.
As I have shown before, Jetson_TX2_NX_Product_Design says the following, what does this mean?
It appears that POWER_EN can be turned off before SHURDOWN_REQ as an option. This is contradictory to your answer.
Ah, I misunderstood your question. Please ignore my comment. We are checking this internally, will update once get result.
The first underlined case is started with SHUTDOWN_REQ* going active, and this signals the carrier board to shut the system down. The carrier board should deassert POWER_EN which will power the system off, and during the powerdown, SHUTDOWN_REQ* will be cleared (to inactive). The second case is if no SHUTDOWN_REQ* has been generated, but instead the design just brings down POWER_EN to power the system off. This is not the preferred method of powering the system off and can result in issue unless SHUTDOWN_REQ* is asserted letting the carrier board know the module should be powered down.
As for the second case you commented on, does SHUTDOWN_REQ mean that it will automatically output an assert after POWER_EN goes low?
I would like to know how SHUTODOWN_REQ works when POWER_EN goes low first.
No, it is not automatically output here and should be asserted manually by the design.
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