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User avatar
By Landru

Can someone set me straight on a problem I've run into? The RTC settings in my OLA do not always persist after the unit is powered down.

Here's a summary of what I've encountered:
1. Set the RTC date and time on OLA via CoolTerm. Works fine.
2. Power OLA down.
3. Power OLA up again and log some data with an attached BMP280.
4. Power OLA down and examine the logs from the SD card. RTC data has persisted and barometer data looks fine. Yay!
5. Put OLA away overnight.
6. Power OLA up again and log some data.
7. Power the OLA down and examine the logs. Barometer data looks fine but RTC has reset. Zoinks. :(

Has my OLA got a bum RTC battery? Or, am I making a bonehead error?

Another possibly related thing I've noticed is that the OLA does not always start to log automatically on power up. Sometimes pressing the reset button is required. Pressing the button may even be necessary when one logging session follows another after only a few minutes of power off. My guess is that the OLA may be going into low power mode. However I have not set that option.

Other than this little hiccup with RTC, the OLA is just what I was looking for to log in-flight data from model aircraft.

Many thanks in advance.
User avatar
By TS-Russell
My first guess would be to suspect the battery...or perhaps how long it is being charged?
The hookup guide ... -guide/all (40% of the way down the section on RTC starts....that one, the 'reset' one, and the 'low power considerations' might combine to point us in a direction) mentions it needing 20mins to charge the RTC clock up (but doesn't say how long that will will last)

Hope this helps!
User avatar
By Landru
Thanks for the good suggestions.

I had wondered whether the RTC battery may not be getting charged. However, since all my logging sessions are at least 20 minutes long, I had set that possibility aside.

Now it occurs to me that the RTC battery may charge only when the OLA is connected via USB. Or, perhaps 1S Lipo battery power is insufficient. (1S Lipo is how I power the OLA for logging.)

Meanwhile, further weirdness has occurred: sometimes the OLA fails to log at all, and now the green Tx LED flashes constantly even when the OLA is not connected via USB.

I'll investigate the charging issue and report back on what I discover.

Many thanks for your help.
User avatar
By Landru
I'm happy to report progress.

First, what didn't work: after charging the OLA via USB for 30 minutes and resetting the RTC data, it failed just as before. That seems to rule out battery charge as a cause.

Then I twigged to another possible culprit: the values I entered when configuring the RTC settings. For example, the prompt in terminal call for the month to be entered as a value from "1-12". Accordingly, I had been entering "6" for June. My moment of inspiration was to suspect that a two-digit entry was actually required i.e. "06".

Sure enough, using two digits for the month seems to have done the trick. The RTC data showed up correctly in the log files from three sessions earlier today. And that's with the OLA having been powered off overnight. Presumably all the RTC data must be entered as two-digits even though the help text for some fields indicates otherwise.

I'm stoked that the RTC problem seems solved. Accurate RTC data is a big plus for my purposes.

The flashing green Tx LED still remains a mystery. The documentation says it indicates USB-C serial traffic. However, I'm seeing it whenever the OLA is logging, with or without a USB connection. Until any significant consequence comes along, I'll consider it a curious quirk.

Then there's the incompatibility of the Apollo3 board definitions with Arduino > 1.8.12. I hope and expect that'll be sorted out at some point. I'm looking forward to unlocking more of the potential of this neat little device.
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