[time-nuts] BC637PCI 1024 week rollover

[GandalfG8 at aol.com]

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