[time-nuts] ***SPAM*** Re: ***SPAM*** Motorola Oncore UT+ firmware upgrade & backup power questions
kb8tq at n1k.org
Sun Mar 15 09:49:16 EDT 2015
The “old almanac” issue is *very* normal for early Oncore modules. Some (possibly custom) firmware times out a stored almanac after
searching for X hours (minutes?). The original firmware did not time out. You can sit there for a *long* time with a bad almanac ….
The real issue is the lack of a running real time clock. With no way to figure out how old the almanac is, the module can’t make a rational
decision about almanac age. By default, the module just saves the last clock value in ram. It starts from what ever time it had last when
the main power comes back on. The app notes on the module recommended clearing the almanac as the solution.
The obvious drawback to the official solution is that you have to do it with firmware. If you have to do that, you might as well re-load
the ram based data from scratch. Essentially all the OEM’s made that decision. Thus we have a lot of modules out there with no
batteries on them.
> On Mar 15, 2015, at 2:36 AM, Mike Cook <michael.cook at sfr.fr> wrote:
>> Le 14 mars 2015 à 19:01, Pete Stephenson <pete at heypete.com> a écrit :
>> On Sat, Mar 14, 2015 at 12:56 PM, Mike Cook <michael.cook at sfr.fr> wrote:
>>>>> 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.
>>> Well, I dug it out and checked the voltage across the CR2032. Down to 2.8volts after 4yrs 3mths. Connected up the receiver ad powered up.
>>> It came up in position hold mode with the coordinates that were stored in 2010. 1PPS is on but I am only seeing 2 sats and am not to sync’d to UTC. I think the almanac may be no good. I’ll leave it a while and see if t recovers.
>>> Anyway. Using a CR2032 is OK, at least with my hardware and you get backup for at least 4 years.
>> Fantastic. Just what I wanted to hear. Thanks for checking.
> Probably was a bad almanac . Maybe in testing, Motorola hadn’t figure the receiver could be off for years . I had to reset the receiver.
> But OK after that. BTW that was firmware 3.2.
>> Also, my apologies for sending a blank reply to the list a moment ago.
>> Pete Stephenson
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