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PiSupply / PiJuice

Resources for PiJuice HAT for Raspberry Pi - use your Pi Anywhere
https://www.pi-supply.com/product/pijuice-standard/
GNU General Public License v3.0
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Section "Sync RTC time at boot" - legacy instructions #1029

Closed bablokb closed 7 months ago

bablokb commented 8 months ago

With a halfway up to date PiOs, you don't need to update the system clock as described in the software-section. This is now automatic once the kernel detects the rtc. In consequence, you just have to add the overlay regardless of the EEPROM-address (as described in the section above).

As a side note: in the section you recommend updating the rtc in /etc/rc.local. Note that /etc/rc.local was already legacy in 1983. 50 years ago.... In modern Linux, you use either udev-rules or systemd-services for things like that. /etc/rc.local is about the last thing that is executed during boot, but updating the system-time should be done as early as possible.

But wait: there is a section ("Repeaded wakups") where you recommend @reboot in the crontab. Now this is really really legacy :-(

tvoverbeek commented 8 months ago

Note: the PiJuice RTC is simulated in the firmware. When Pi/PiJuice are both off the RTC is not running, so you canot rely on the PiJuice RTC to have the correct tie at boot. Basic issue is the OS detecting a DS3239 (clock with alarm) due to the device tree fragment in the HAT eeprom. 2 captains controlling the RTC does not work.

bablokb commented 7 months ago

I rechecked and adding the overlay works just fine. The system time will be automatically updated from the RTC and I can still control the alarm and wakeup from the gui. The RTC also does not loose it's time either as long as there is a power source (usb or battery) connected.

tvoverbeek commented 7 months ago

Closing this. If you do not agree, please reopen it