TX2 Recovery pin difference vs. TX1

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hi Guys,

I have an odd observation.

If I plug a TX1 into my carrier board and power on while holding RECOVERY button it does enter recovery mode.
Also - if the board is powered on and I hold RECOVERY low and toggle RESET_IN it also does enter recovery mode.

If i plug in a TX2 I’m unable to enter recovery mode using the two different methods above and I have to unplug the TX2 and put it into the development board to flash it which is quite annoying.

Some information about my carrier board:

Jetson is powered with +8V and the VIN_PWR_BAD (B8) pin is connected to the “Power Good” signal of the +8V regulator.

RESET_OUT is connected to my carrierboards +1.8V Power Good signal which is the last supply to be turned on.
RESET_IN is tied to a push button that goes to ground and there’s no pull up connected.

CARRIER_POWER_ON signal asserts a LM3880 power sequencer that turns on 5V then 3.3V and finally 1.8V with 16mS delay between each supply turning on.

Once the 1.8V starts then it’s Power Good signal will release RESET_OUT on the jetson.

Can you explain me what differences there are between the FORCE RECOVERY circuit on TX1 vs. TX2 ?

Regards
Lasse

3

Hi, TX1 and TX2 share same carrier board design, not sure why yours only works with TX1. Maybe you can probe the related signals and compare to that with dev kit carrier board.

The circuit you mentioned seems no problem, but not sure about others, you can check all your design based on the checklist sheet in product design guide to see if any difference.

4

I am just wondering if the button down hold for the failure case is from manually holding down buttons for a significant amount of time, or if the button hold for force recovery mode is in some way automated or through a solid state relay? If both are manual buttons I have no idea why this would fail on your carrier board, but if this is in some way automated perhaps time or voltage drop over a relay would be an issue.

5

Hi All,

My recovery button is a physical button and the RESET pin is tried to a button also.

I found the problem however, I was using the SLEEP pin to drive a FET that had internal pull-down and the RM says that this pin must not be pulled down for RECOVERY to work on TX2

Sure enough - removing the FET so that SLEEP was left floating made it work…