Jetson Xavier NX, disable RTC battery charger

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
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I want to disable the RTC battery charger function, but i can only find examples on how to do this with the kernel builder. I already have the device up and running fine but now i need to disable the battery charger function.

Is there a way to disable the battery charger without having to rebuild the kernel/re-flash the device?

This is my first time using NVIDIA Jetson devices so perhaps i am missing something very basic.
Any help is appreciated

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Sorry for the late response, have you managed to get issue resolved or still need the support? Thanks

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Hi , we still need support, we are running A Jetson Xavier NX module and want to disable the RTC backup battery charger. WE made the image on a virtual machine (Ubuntu 18.04 64bit).
Hoping you can help,

Kind regards,
Koen

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please check

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Hi WayneWWW,

We are having some trouble disabling the battery charger. after adding your advised change it seems to be still enabled. below are the steps we have taken to try to disable the battery charger along with additional information about our setup:
setup:

  • Xavier NX module with custom carrier board (based around the “P3509-A01 Jetson Xavier NX Carrier Board”)
  • Host system for configuration and image building: Linux Ubuntu 18.04.

Image building/ adaptation steps:

  • Get base image files with the NVidia SDKManager tooling.

  • Run installer until image is ready and it asks to flash target >> skip flashing.

  • close installer

  • Make changes in resulting image files, located: /nvidia/nvidia_sdk/JetPack_5.1_Linux_JETSON_XAVIER_NX_TARGETS/Linux_for_Tegra/bootloader/t186ref/BCT/

  • Changed file:
    tegra194-mb1-bct-pmic-p2888-0001-a04-E-0-p2822-0000.cfg

location:
Linux_for_Tegra/bootloader/t186ref/BCT/tegra194-mb1-bct-pmic-p2888-0001-a04-E-0-p2822-0000.cfg

added ‘pmic.system.block[2].commands[1].0x04.0x01 = 0x0;’ to “pmic.system.block[2]”

resulting configuration pmic.system.block[2]:
pmic.system.block[2].type = 1; #I2C
pmic.system.block[2].controller-id = 4;
pmic.system.block[2].slave-add = 0x78; # 7BIt:0x3c
pmic.system.block[2].reg-data-size = 8;
pmic.system.block[2].reg-add-size = 8;
pmic.system.block[2].block-delay = 10;
pmic.system.block[2].commands[0].0x1A.0xFF = 0x28; # SD4 to 1.1V
pmic.system.block[2].commands[1].0x04.0x01 = 0x0;

// Rebuild image

  • run “./apply_binaries.sh” to create new image.

// Flash module

  • run ./flash.sh “jetson-xavier-nx-devkit-emmc” “mmcblk0p1”

Image buiding and flashimg of the module seem to go correctly according to terminal ouptut.

  • Restart module after flashing >> still measuring 3V on the battery connection.

we also tried these steps but with the target file being (same configuration change):
“tegra194-mb1-bct-pmic-p3668-0001-a00.cfg”
location:
Linux_for_Tegra/bootloader/t186ref/BCT/tegra194-mb1-bct-pmic-p3668-0001-a00.cfg

Are we correctly rebuilding the image using the “./apply_binaries.sh” command or do we need to take other actions to rebuild.

Any help would be appreciated.

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please also disable it in kernel.

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Hi WayneWWW,

Apologies for the late response, i completely forgot.
These commands disable the battery charger correctly and we can use this for testing (in the final image we’ll want to disable it via device tree options but for now this will work).

Thank you for your support.

Kind regards.
Koen

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