[time-nuts] ***SPAM*** Motorola Oncore UT+ firmware upgrade & backup power questions

Mike Cook michael.cook at sfr.fr
Fri Mar 13 18:47:07 EDT 2015

> Le 13 mars 2015 à 21:33, Pete Stephenson <pete at heypete.com> a écrit :
> Hi all,
> After a few years of using a Garmin GPS 18x LVC for timekeeping, my
> budget now allows for some upgrades and I had a small field day on eBay:
> I acquired a Trimble Thunderbolt, two Trimble Resolution Ts, and two
> Motorola Oncore UT+s (seconds purchased for spares and testing).
> The documentation for the Trimbles is clear, but I had several questions
> regarding the Oncores that I was unable to find clear answers to online.
> I would be very much obliged if the folks here might be able to help.
> 1. Is it possible to upgrade the firmware on the Oncore UT+? If so,
> where can one acquire the latest firmware (3.2, I believe) files and how
> would go one about installing it? Is this something WinOncore can do? I
> ask because the receivers on eBay are of varying vintage and may not be
> fully upgraded.

The WinOncore12 application has an option to download firmware but I have not been able to find a source of firmware. 

> Since Motorola exited the GPS business a relatively long time ago,
> firmware updates and directions have proven difficult (impossible so
> far) for me to find.
> 2. The two Oncores I purchased were not factory-equipped with a
> rechargeable battery. The user guide says that one can apply "Externally
> applied backup power (< +5V)" to pin #1 in order to maintain data in RAM
> in case the main power is interrupted.
> Can one use a common non-rechargeable coin-cell battery like a CR2032 to
> provide this backup power, or does it need to be a rechargeable battery?
> Will a CR2032 or the Oncore itself be damaged if such a cell is used?
> 3. Tom says at
> <http://lists.ntp.org/pipermail/questions/2012-October/034001.html> that
> in addition to being an input for external backup power, pin #1 on the
> Oncore provides current-limited 5V for battery/supercapacitor charging.
> Is this true for Oncore receivers that were not factory-equipped with a
> rechargeable battery?

I don’t recall detecting any voltage on that pin.

> If true, what is the maximum current that can be
> safely supplied by the pin? As above, is it safe to use a
> non-rechargeable battery like a CR2032?

 I have a couple of UT+ receivers which were not equipped with batteries and I used a CR2032 for backup without any issue. They were disconnected sometimes for considerable periods on a number  of occasions and the saved data was always accessible on power up.  I don’t know how long a battery like that lasts. I have one, powered off, still with the battery in circuit that I pulled in 12/2010. Hmmm. might be worth powering it on to see.

> If pin #1 can supply power and I wanted to charge a supercapacitor from
> that pin, would I also need to include a current-limiting resistor to
> prevent the Oncore from sourcing too much current?
> I could find nothing in the user guide that says that pin #1 can be used
> for charging a battery.
> <http://www.synergy-gps.com/images/stories/ShopTalk/9backup_battery_considerations.pdf>
> is unclear on whether or not pin #1 can be used for charging batteries,
> or if it's safe to use non-rechargeable cells like a CR2032 coin-cell
> battery.
> 4. The user manual and the battery backup considerations document says
> that the Oncore UT+ draws 5-100 uA (15uA typical) from the backup power
> source. Is this a constant draw, even when the main 5V power is being
> supplied to the unit, or does the unit only draw current from the
> battery when the main power is interrupted?


> I'd measure it directly, but none of my multimeters are able to
> accurately measure microamperes.
> Thank you all for your time and assistance. If any other time-nuts
> happen to make it to Bern, Switzerland in the next few years, please let
> me know and drinks are on me.
> Cheers!
> -Pete
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