RTC doesn't survive power cycle

[mck1117]

Reports that the real time clock (ie, SD card timestamps) doesn't work if you power cycle the ECU, even with an RTC battery installed

[rusefillc]

Status update:

There is FOME-Tech/ChibiOS@7ed8236 and FOME-Tech/ChibiOS@12c805f within stable_21.11.x.FOME

but https://github.com/FOME-Tech/fome-fw/blob/master/.gitmodules does not seem to use https://github.com/FOME-Tech/ChibiOS?

@nmschulte do you know anything about all that? Any interest in a common ground customEfi naming convention for FOME-Tech/ChibiOS@12c805f?

[nmschulte]

@nmschulte do you know anything about all that?

I have no real comment or position other than that I see the value in FOME-Tech/ChibiOS, and purposefully made the port and rename separate commits. (https://github.com/FOME-Tech/ChibiOS/pull/1/commits)

The first thing that comes to mind as a solution is to (agree to) simply drop the prefix on the names (a la STM32_LSE_WAIT_MAX...) and just extend the ChibiOS namespace directly and without qualification.

[rusefillc]

@nmschulte my main question is if RTC works and/or if anyone knows why RTC does not work in what scenarios?

The namespace question is secondary I would suggest CUSTOM_ or CUSTOM_EFI_ or anything else really as long as it's clear that it's not original ChibiOS I guess?

[nmschulte]

I see. w/re: ChibiOS 21, it has not landed: #385; I'm unsure if it resolves this issue or what might stand in the way of answering (that is, like, what's it need yet?).

I'm not sure of the scenario other than vaguely FOME Proteus RTC doesn't survive reboot power cycle, and since a while now. It could be due to LSE_MAX_WAIT, though I suspect not, but easy to test by setting RTCSEL to LSI and observing. Otherwise I don't see the culprit in firmware code yet; if I understand correctly, from the LSE_MAX_WAIT code and the datasheet, the backup domain will be reset on every boot (and try to await LSE, before applying RTCSEL), but datasheet suggests RTC/backup RAM should be retained. I haven't found time to reproduce or debug anything yet.