[aprssig] Re: Emergency comms

Dave Baxter dave at emv.co.uk
Tue Aug 30 11:37:00 EDT 2005

What I was hoping to hear!

I guess the use of watchdog timers and brownout detection is
implemented.  There is no reason why the TT (or SOTT) can't do the same,
especialy on the bigger chips with internal FLASH/NOVRAM, but it needs
work and coding of course.  And as in all thing's is easier to implement
from the very start, rather than add later...

Of course it could also be due to better PSU circuitry, low dropout
reg's etc.

Good news anyway..

73  Dave.

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Curt, WE7U
> Sent: Tuesday, August 30, 2005 4:25 PM
> To: TAPR APRS Mailing List
> Subject: [aprssig] Re: Emergency comms
> On Tue, 30 Aug 2005, Dave Baxter wrote:
> > Here's one for Scot and the OpenTracker project.  Can it survive a 
> > brownout reliably, or a short term dropout (less than that 
> needed for 
> > a full reset) without locking up, or corrupting stored data 
> that was 
> > waiting to be TX'd?  Not many (if any) of the "classic" TNC's can, 
> > that I do know, and as for most things PC based, well...  
> OK, OK, yes 
> > yes I know laptops have internal batteries, but what about the 
> > attached TNC/Radio?  And the also "Attached" software.  
> Ui-View goes 
> > into abject raptures if the TNC or D7 it's using, "burps"...
> I know you said that was for Scott, but I know from personal 
> experience that my OpenTracker has not ever lost it's configs 
> during engine start (undervoltage), whereas my TinyTrak-II 
> would lose its configs every once in a while (happened at 
> least three times).
> I suspect that has to do with the processor itself and how it 
> performs during undervoltage.  The OpenTracker and the 
> TinyTrak's use different processors (different manufacturers even).
> Sometimes the TT-II would fail to operate during part or all 
> of my commute but then the next commute it would be fine.  A 
> friend of mine had similar problems and suggested that it 
> might have to do with receiving the GPS stream at the wrong 
> time on startup, and so sounds like a firmware issue.  In 
> that case, that particular problem may be solved on later units.
> In any case, the OpenTracker has proven more reliable in my 
> particular mobile setup.  With the APO switch by James 
> Jefferson added in there as well I don't have to touch power 
> wiring or power switches on my mobile setup at all which 
> makes it even more reliable.
> --
> Curt, WE7U.

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