AW: AW: [basicstamps] Urgent Brownout help
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Hi Beau,
thanks for the advice but would the ATN problem cause such a 'sleep'
at all?
The display has its own power supply, only ground is connected to the stamp
8and the signal of course).
Tracy, does that mean that if the resonator stops or slows down the stamp
might just stop in the middle of a program without going on and without
restarting? As this is an outside promotion there might be humidity, the
stamp doesnot get wet or anything but the humidity might be pretty high.
I did replace the stamp with another, but that did not change a thing...
So if Beau is right I shouldnot tie ATN to ground?
I will go to sleep now and in the morning I will run to my desk like it was
christmas and look for more advice :-)
Thank you all very very much,
Uli
Urspr
thanks for the advice but would the ATN problem cause such a 'sleep'
at all?
The display has its own power supply, only ground is connected to the stamp
8and the signal of course).
Tracy, does that mean that if the resonator stops or slows down the stamp
might just stop in the middle of a program without going on and without
restarting? As this is an outside promotion there might be humidity, the
stamp doesnot get wet or anything but the humidity might be pretty high.
I did replace the stamp with another, but that did not change a thing...
So if Beau is right I shouldnot tie ATN to ground?
I will go to sleep now and in the morning I will run to my desk like it was
christmas and look for more advice :-)
Thank you all very very much,
Uli
Urspr
Comments
>might just stop in the middle of a program without going on and without
>restarting? As this is an outside promotion there might be humidity, the
>stamp doesnot get wet or anything but the humidity might be pretty high.
>I did replace the stamp with another, but that did not change a thing...
Yes, high humidity could do it too. A layer of moisture on the
circuit board could stop the oscillator. The oscillator input is a
very sensitive point in the circuit. The problem would be aggravated
by any residue (coffee stain??!) on the circuit board. A drop of
silicone "conformal coating" would help, as would putting the whole
circuit in a box with desiccant.
In re-reading your post, it does sound like the program is just
stopping in the middle and subsequently continuing on from where it
left off, rather than resetting and starting from the beginning. Is
that what you are seeing, are you sure?
The effect of the ATN pin would be to restart it from the beginning.
On the other hand, stopping the clock might just put it into
suspended animation. However, I am not sure of that, because I think
the watchdog timer might still be active and would attempt to reset
the chip even if the clock stops. Just not sure.
>
>So if Beau is right I shouldnot tie ATN to ground?
I think it can't hurt. Connecting that point to ground effectively
short circuits both AC and DC voltages at that point.
-- Tracy
> >Tracy, does that mean that if the resonator stops or slows down the stamp
> >might just stop in the middle of a program without going on and without
> >restarting? As this is an outside promotion there might be humidity, the
> >stamp doesnot get wet or anything but the humidity might be pretty high.
> >I did replace the stamp with another, but that did not change a thing...
>
>Yes, high humidity could do it too. A layer of moisture on the
>circuit board could stop the oscillator. The oscillator input is a
>very sensitive point in the circuit. The problem would be aggravated
>by any residue (coffee stain??!) on the circuit board. A drop of
>silicone "conformal coating" would help, as would putting the whole
>circuit in a box with desiccant.
Condensation could easily happen if you are moving the unit from the nice
"cool" indoors to perhaps a not so nice "hot", high humidity outdoors.
>In re-reading your post, it does sound like the program is just
>stopping in the middle and subsequently continuing on from where it
>left off, rather than resetting and starting from the beginning. Is
>that what you are seeing, are you sure?
>
>The effect of the ATN pin would be to restart it from the beginning.
>On the other hand, stopping the clock might just put it into
>suspended animation. However, I am not sure of that, because I think
>the watchdog timer might still be active and would attempt to reset
>the chip even if the clock stops. Just not sure.
>
> >
> >So if Beau is right I shouldnot tie ATN to ground?
>
>
>I think it can't hurt. Connecting that point to ground effectively
>short circuits both AC and DC voltages at that point.
>
> -- Tracy
Tracy,
You are correct. I guess the point being that you could connect
the ATN line to either VDD or GND with similar results. GND as
the more obvious solution.
Beau Schwabe Mask Designer IV - ATL
National Semiconductor Enterprise Networking Business Unit
500 Pinnacle Court, Suite 525 Wired Communications Division
Mail Stop GA1 Norcross, GA 30071
>Condensation could easily happen if you are moving the unit from the nice
>"cool" indoors to perhaps a not so nice "hot", high humidity outdoors.
...or when the humidity is high during the day and the temperature
then drops in the evening. The surface of the board drops below the
dew point and condensation forms. Even a microscopic thin layer.
A small heater (resistor) in a small enclosure could help with that
too, if you have power available. Or simply add a resistive load on
one of the Stamp outputs, to heat it up a bit. It is odd though,
because usually the operating heat of the circuit would be enough to
keep condensation from forming.
-- Tracy