Tx2 nx power

[2634100881]

Hi，I have two questions aboutTX2 NX.
1、we are designing our carrier board with TX2 NX. we want to design the system can be auto power-ON without the button MCU(EFM8SB10F2G) to simplify our design.
Is that okay?
2、Whether there is a reference design for auto power-ON？

[Trumany]

Hi, you can refer to the Power ON/OFF Logic page in P3449_B01 schematic for auto-power-on design.
Jetson Nano Developer Kit Carrier Board Design Files (P3449 B01)

[2634100881]

thanks，Does the design you’re talking about need to modify the circuit? Can it be used directly on TX2NX?

[Trumany]

You should take it as reference and make custom change on your board. The key point is to enable POWER_EN >400ms after main power supply is stable.

[2634100881]

thanks，
I have a question about power down sequence；

As shown in Figure 5-5 below, only the time sequence between each signal is given in the power-off time sequence, and no clear time requirement is given. Can we not strictly observe the time, but just ensure the time sequence?

[Trumany]

Yes, it is just sequence for those without specific data, the timing is not so strict.

[2634100881]

thanks；

About the description in the picture above“The carrier board cannot drive high or pull high any signals that are associated with the module when the module rails are off.”
I have two questions，
1、”the module rails are off“
Does this refer to 3.3V and 1.8V power supplies？Whether 5.0V power supply is included
2、“The carrier board cannot drive high or pull high any signals that are associated with the module”.
Does the signal in this sentence refer to the Open Drain signals in the module？As shown in the red box below.

[Trumany]

That is to make sure the module pins status won’t be affected by carrier power rails when module is power-off. You can get that in the power off sequence that module should be power off first and then the carrier rails.