I also have an RTC issue, where the clock (and date) hangs after a power-off, and is the same when I power it on (it doesn't reset to 2009, it is exactly the same time and date as just before I powered down), and continues to "tic" (i.e. it keeps going second-to-second) after the unit is turned on. I don't believe to be a problem with the backup battery, as it would have reset to 2009. Can anyone confirm my bug?
Hi, this is a (late) follow-up on my RTC problem. I've finally gathered the nerves to troubleshoot it. After some analysis, and datasheet reading, I was convinced that the only culprit is the 32.768KHz quartz crystal resonator. My hypothesis was also backed-up by running "hwclock" via UART console. It's return value (date, time) was the same as the last manual setting (via the DSO's Utility menu), even if the unit was powered-cycled, meaning that the RTC's external source clock wasn't working (or the SoC was defective, but I didn't even dare to consider that
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
). After a quartz replace, it's finally working! Hope it helps others with similar issue.
EDIT: The day after my initial mod (the quartz replacement), my unit's hardware RTC still stalled. So, I've checked the SoC datasheet (
http://www.wvshare.com/datasheet/SAMSUNG_PDF/S3C2416.PDF) yet again, and noticed on page 13-6 (page 310) the crystal connection schematic: the 5MOhm resistor in series with the crystal is emphasized in another color, and also circled in red, giving the impression that this addition is seemingly an manufacturer after-thought. I've checked my board, it didn't include such resistor, also confirmed by the low impedance across the board's crystal pads. Thus, I've soldered an 5M1 0603 SMD resistor, and now it seems to work perfectly (at least for the past hour or so). It may be possible that I'm in possession of a early revision board, and that's why no other user reported the same issue. Hope it helps!