[time-nuts] BC637PCI 1024 week rollover
GandalfG8 at aol.com
GandalfG8 at aol.com
Mon Feb 10 10:15:46 UTC 2014
Ah, I took 1999 as I thought that was the only relevant date for another
1024 weeks, I'm not familiar with the shifted 1024 week period so will take a
look at that.
Does "shifted" imply a shift at the whim of the manufacturer, ie could it
explain why these boards might have been ok a few years ago but not now?
Oh dear, I think a wee light bulb has just exploded:-)
I haven't checked this yet, but if shifting means to start a 1024 week
period that's approximately from or not too far before the date of
manufacture, either for individual units or just as a ballpark for a given production
run, that would buy them nearly twenty years from then, which would mean
these boards should still be ok.
If shifting means to do this say at the design stage or starting with the
first production run then they might buy twenty years from then but
regardless of individual manufacturing date.
I'm not too sure that even the earliest of these boards should be twenty
years old yet, but if plan Z was to stick with some previously picked
arbitrary date, such as company formation or granny's birthday, then that might
well be the answer:-)
Thank you, will definitely look more closely at this, perhaps it's not time
yet to put the boards back into hibernation after all:-)
I agree re the TMS29F010, and I'm sure I could read it, but would
definitely need an adapter for that.
Regards
Nigel
GM8PZR
In a message dated 10/02/2014 01:40:44 GMT Standard Time,
magnus at rubidium.dyndns.org writes:
It probably operates on a shifted 1024 week period and that was probably
not changed after the original code was written. Obviously the shifted
wrapping has now occurred.
1999 is only relevant for the non-shifted 1024 period.
> It is possible to set the board for other than GPS, (Timecode,
Freerunning,
> or 1PPS) but I suspect I might then loose the conditioning, something
I'd
> need to check. Either way, I'd like to have the correct GPS date too if
> possible, but it's the conditioning that's of more interest so I'd do
without
> the correct date if needs be.
>
> I've identified two programmable devices, the version H manual with
> schematics is very useful:-), the first being a OTP configuration PROM
for the
> Spartan FPGA and the other a TMS29F010 flash mamory IC which I suspect
holds
> the firmware. That is socketed but I don't think I have the necessary 32
> pin quad adapter to be able to read it.
It would be the TMS29F010 flash which would be of interest.
> This was only intended to be a quick test, funny how "quick tests" soon
> become major projects:-), so these might have to go back into
hibernation
> again shortly, for the time being at least.
Fair enough!
Cheers,
Magnus
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