Rtc0 not working

Robotics & Edge Computing Jetson Systems Jetson Orin Nano
1

I am using an 8GB Orin Nano (P3767-0003) on a custom carrier board that mimics the Nvidia Developer kit carrier board (P3768-0000).
I am unable to read from rtc0. Would anybody know any additional debug I can do in software? Below is my output from reading rtc1 and rtc0.
I have a 3V coin cell going to pin 235 (PMIC_BBAT) through the reverse protection diode (D4), as per the Nvidia Dev Kit Schematic.

~$ sudo hwclock --show --verbose -f /dev/rtc1
hwclock from util-linux 2.37.2
System Time: 1609462230.429967
Using the rtc interface to the clock.
Last drift adjustment done at 1609459209 seconds after 1969
Last calibration done at 1609459209 seconds after 1969
Hardware clock is on UTC time
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
...got clock tick
Time read from Hardware Clock: 1970/01/01 00:49:23
Hw clock time : 1970/01/01 00:49:23 = 2963 seconds since 1969
Time since last adjustment is -1609456246 seconds
Calculated Hardware Clock drift is 0.000000 seconds
1970-01-01 00:49:22.440492+00:00

$ sudo hwclock --show --verbose -f /dev/rtc0
hwclock from util-linux 2.37.2
System Time: 1609462234.917699
Using the rtc interface to the clock.
Last drift adjustment done at 1609459209 seconds after 1969
Last calibration done at 1609459209 seconds after 1969
Hardware clock is on UTC time
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
hwclock: select() to /dev/rtc0 to wait for clock tick timed out
...synchronization failed

I am using JP 6.1.0 L4T 36.4.
I have found this forum post from someone else having the same problem, and the marked solution is that there was a bug in JP6.0 DP (R36.2) but it is fixed in JP6.0 R36.3
rtc issue
Please advise if this has regressed in JP6.1.0 - or what the solution is.

3

What I am finding is not everything they offer is on the same page.
jp6.1 r36.4

This is from sdkmanager install onto NVMe, some stuff in it does not work. However the clock problem does not seem to be present.

fred@ubuntu:~$ sudo hwclock --show --verbose -f /dev/rtc0
[sudo] password for fred: 
hwclock from util-linux 2.37.2
System Time: 1734493565.963996
Using the rtc interface to the clock.
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
...got clock tick
Time read from Hardware Clock: 2024/12/18 03:46:07
Hw clock time : 2024/12/18 03:46:07 = 1734493567 seconds since 1969
Time since last adjustment is 1734493567 seconds
Calculated Hardware Clock drift is 0.000000 seconds
2024-12-17 22:46:06.322778-05:00
fred@ubuntu:~$ sudo hwclock --show --verbose -f /dev/rtc1
hwclock from util-linux 2.37.2
System Time: 1734493576.892169
Using the rtc interface to the clock.
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
...got clock tick
Time read from Hardware Clock: 1970/01/01 02:36:00
Hw clock time : 1970/01/01 02:36:00 = 9360 seconds since 1969
Time since last adjustment is 9360 seconds
Calculated Hardware Clock drift is 0.000000 seconds
1969-12-31 21:35:59.144651-05:00
4

So, r36.4 don’t have problem for you?

5

It doesn’t appear @foxsquirrel1 has the issue on Jp6.1 r36.4. We also see the correct behavior on our Orin Nano devkit running Jp6.1 r36.4. Its only when we are on our custom carrier board we have this issue.

6

So, the problem is on customized carrier board no matter r36.4?

7

Yes, The issue is now resolved, we found an issue on our carrier board disign, and after fixing it now works. Thanks for your help @foxsquirrel1 for testing the rtc readback

9

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.