Hello, I am using JetPack 4.6.3 (L4T 32.7.3 ) on Jetson AGX Xavier device. Surprisingly, the voltage across the supercapacitor (C512) is always 0 V (whether turned on or off). It was suggested here to enable the “backup-battery” by the device tree. I did it but had no success. The “backup-battery”…

Looks like board issue. You can run RMA for it.

Did you sync the time to RTC? sudo hwclock -r -f /dev/rtc0

[image] ShaneCCC: Did you sync the time to RTC? No. How to do it?

nvidia@nvidia-desktop:~$ sudo timedatectl set-ntp off nvidia@nvidia-desktop:~$ sudo timedatectl Local time: 三 2022-10-26 12:41:11 CST Universal time: 三 2022-10-26 04:41:11 UTC RTC time: 三 2022-10-26 04:41:12 Time zone: Asia/Taipei (CST, +0800) System clock synchronized: yes NTP service: inact…

@ShaneCCC Here is the update. I tried as you suggested but had no success. Below are the details: In the commands above, you used /dev/rtc0 and rtc1. So, I checked which one to use. $ dmesg | grep rtc [ 0.814461] iommu: Adding device bc00000.rtcpu to group 23 [ 1.000406] vdd-rtc: at 800 mV …

After disable tegra RTC you should only have rtc0. Does any kernel message to load the time from rtc0?

Modify “rtc@c2a0000” back and reference to below topic to verify. [image] RTC can't hold time the after system rebooted in L4T 35.1 Jetson AGX Xavier @matanh Modify kernel configure to modify CONFIG_RTC_HCTOSYS_DEVICE to rtc0 to build new kernel for it. Thanks

[image] ShaneCCC: After disable tegra RTC you should only have rtc0. Does any kernel message to load the time from rtc0? Yes. rtc0 is registered as shown below: $ dmesg -T | grep rtc [Tue Sep 6 12:17:58 2022] iommu: Adding device bc00000.rtcpu to group 23 [Tue Sep 6 12:17:58 2022] vdd-rtc…

No, the RTC time is incorrect. You need set it by “sudo hwclock -r -f /dev/rtc0” [image] RaviJoshi: RTC time: Sat 2000-01-01 01:03:54

@ShaneCCC Thank you very much. [image] ShaneCCC: No, the RTC time is incorrect. Yes, you are right. That is the problem. [image] ShaneCCC: You need set it by “sudo hwclock -r -f /dev/rtc0” I set it again. The problem persists. Please see below: I set the time manually.$ timedatect…

Looks like the RTC time didn’t keep by the supercapacitor. Could you check the kernel log to by dmesg | grep -i rtc

Supercapacitor shows 0V even when powered on

Robotics & Edge Computing Jetson Systems Jetson AGX Xavier

ShaneCCC May 11, 2023, 5:12am 24

Modify “rtc@c2a0000” back and reference to below topic to verify.

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Supercapacitor shows 0V even when powered on

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