AW: [basicstamps] Urgent Brownout help
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Hi Al,
thanks for the idea, I will try it though I have no wire at the ATN line at
all. Do you have any idea what strange kind of state this stamp could be in?
Thanks again,
Uli
Urspr
thanks for the idea, I will try it though I have no wire at the ATN line at
all. Do you have any idea what strange kind of state this stamp could be in?
Thanks again,
Uli
Urspr
Comments
I think I am sure because I debugged the action permanently and when this
state uccured the debug stopped and also the quadravox kept on playing
instead of restrting the soung every second like it should when the stamp
runs. Third indicator was the Counter (LCD-Panel) that stopped counting
until the stamp came back to life. I absolutely know that it was no brownout
because then I would have had to push the start-button to start a new game
and the counter would have been reset.
I don't have the code on this PC, so I can't show you but I don't think it
can be the code because most of the time it works just fine, and no code can
make the stamp fail after a restart...(there is not even read or write in
the code)
Thanks for your help, Leroy. Sincerely, Uli
Urspr
A brown out, to me, means the supply voltage falls below the point (4.3
volts) that allows the cpu to run. If the voltage did in fact take a
dip, when you press reset, I would expect the thing to resume normal
operation. What I am hearing from you is that the CPU stops running and
will not restart until after a time period has elapsed. Could there be
over heating - from over voltage? You said you replaced the CPU and the
symptoms still remain. A spike on the atten line might reset, but then
it should restart right away, unless the voltage there remained and that
don't make sense if it restarts after a couple of hours.
Strange problem, but I am sure it's about to go away [noparse]:)[/noparse])))))))))
Leroy
ulibasic wrote:
>
> Hi Leroy,
>
> I think I am sure because I debugged the action permanently and when this
> state uccured the debug stopped and also the quadravox kept on playing
> instead of restrting the soung every second like it should when the stamp
> runs. Third indicator was the Counter (LCD-Panel) that stopped counting
> until the stamp came back to life. I absolutely know that it was no brownout
> because then I would have had to push the start-button to start a new game
> and the counter would have been reset.
>
> I don't have the code on this PC, so I can't show you but I don't think it
> can be the code because most of the time it works just fine, and no code can
> make the stamp fail after a restart...(there is not even read or write in
> the code)
>
> Thanks for your help, Leroy. Sincerely, Uli
>
>
Urspr
>
>thanks for the idea, I will try it though I have no wire at the ATN line at
>all. Do you have any idea what strange kind of state this stamp could be in?
>
>Thanks again,
>
>Uli
That would be my first try too, to ground the ATN line if it is not being used.
Any chance that you have condensation on your circuit board? If
there is a residue on the board between the +5 volts and the ATN
pin, the leakage can be enough to make the stamp go dead for a while,
until the board warms up or dries off. Grounding ATN should stop
that, and cleaning and sealing the circuit board could help too.
It is not unusual that you could stop the Stamp by putting your
finger on the resonator. The oscillation is quite sensitive to stray
capacitance, and if you play with it you can get it to operate at the
wrong frequency or stop altogether. However, a bad oscillator on the
Stamp is an unlikely culprit, especially if the board is still clean
and dry. If you have a spare stamp there you can pretty well rule out
the possibility of a bad chip or bad resonator.
-- Tracy
would cause
a reset, Noisy electrical environment is likely the main culprit. In fact,
after
revisiting the BS2-schematic it would not do you any good to connect the
ATN to Vdd
or GND. The initial capacitor essentially blocks DC but allows an AC
signal or
random noise to enter.. See below
http://www.parallaxinc.com/downloads/Documentation/oems/OEM%20BS2/OEM%20BS2%20Sc\
hematic.PDF
Simplified BS2 Schematic(focus ATN):
ATN>---||--o--||
o---->GND
.1uF | .1uF |
| 10K 10K |
o
/\/\--o--/\/\---o
| |
10K | |
Vdd>
/\/\---o--C B E
o
| (2N3904)
|
RST>
o
> To MCLR (PIC16C57)
Note: This built-in DC-Blocking filter with the capacitors did not exist
in the earlier BS2 front end when some of us started out. So an
earlier time allowed you to connect directly to the ATN with results.
...In order to prevent RESET, you could "beef-up" the 10K pull-up resistor
between
Vdd and RST by adding another 10K in parallel. I wouldn't tie this pin
directly
to Vdd, or you could risk damaging the NPN transistor, and you won't be able to
program your BS2 if this happens.
Have you tried isolating power between the BS2 and the "big
LCD-Display"? This
doesn't need to be elaborate, just a simple DIODE capacitor blocking technique
on the supply to each device.
o
>+Stamp
| +
o-->|--o--||--o
| 100uF |
Main Power +>---o o--->GND (to ALL)
| 1000uF|
o-->|--o--||--o
| +
o
>+LCD-Display
>Hi Al,
>
>thanks for the idea, I will try it though I have no wire at the ATN line at
>all. Do you have any idea what strange kind of state this stamp could be in?
>
>Thanks again,
>
>Uli
>
>
>
>
Urspr
Thanks very much, Uli
Urspr
a disconnected antenna (albiet a short one). So grounding it can help by
making sure there is no noise on that part of the line for the capacitor
to grab. Anyway, it can't hurt. I've definitely seen this help when
there is a long run of wire on ATN.
Al Williams
AWC
* Floating point A/D
http://www.al-williams.com/awce/pak9.htm
>
Original Message
> From: Beau Schwabe [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=m1QllVHI8k2Y74blLWIy0YOfeNvPwkcYQOiZd1-DkwQjaN_CVBfdR3ooAHlTMVhs_QKQAL-HKeE04eQeoc1CBrUIQw]bschwabe@a...[/url
> Sent: Thursday, June 13, 2002 4:29 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: AW: [noparse][[/noparse]basicstamps] Urgent Brownout help
>
>
> For the most part there doesn't need to be a wire at the ATN
> line that
> would cause
> a reset, Noisy electrical environment is likely the main
> culprit. In fact,
> after
> revisiting the BS2-schematic it would not do you any good to
> connect the
> ATN to Vdd
> or GND. The initial capacitor essentially blocks DC but allows an AC
> signal or
> random noise to enter.. See below
>
> http://www.parallaxinc.com/downloads/Documentation/oems/OEM%20
> BS2/OEM%20BS2%20Schematic.PDF
>
>
> Simplified BS2 Schematic(focus ATN):
>
> ATN>---||--o--||
o---->GND
> .1uF | .1uF |
> | 10K 10K |
> o
/\/\--o--/\/\---o
> | |
> 10K | |
> Vdd>
/\/\---o--C B E
o
> | (2N3904)
> |
> RST>
o
> To MCLR (PIC16C57)
>
>
> Note: This built-in DC-Blocking filter with the capacitors
> did not exist
> in the earlier BS2 front end when some of us started
> out. So an
> earlier time allowed you to connect directly to the
> ATN with results.
>
>
> ...In order to prevent RESET, you could "beef-up" the 10K
> pull-up resistor
> between
> Vdd and RST by adding another 10K in parallel. I wouldn't
> tie this pin
> directly
> to Vdd, or you could risk damaging the NPN transistor, and
> you won't be able to program your BS2 if this happens.
>
> Have you tried isolating power between the BS2 and the "big
> LCD-Display"? This
> doesn't need to be elaborate, just a simple DIODE capacitor
> blocking technique on the supply to each device.
>
> o
>+Stamp
> | +
> o-->|--o--||--o
> | 100uF |
> Main Power +>---o o--->GND (to ALL)
> | 1000uF|
> o-->|--o--||--o
> | +
> o
>+LCD-Display
>
>
>
> >Hi Al,
> >
> >thanks for the idea, I will try it though I have no wire at the ATN
> >line at all. Do you have any idea what strange kind of state
> this stamp
> >could be in?
> >
> >Thanks again,
> >
> >Uli
> >
> >
> >
> >
Urspr
its not that I do't want to show the project, I simply donot have it here
now, I will post it as soon as possible. Of course you are right, it is
better to see the bear and then shoot...
No, quadravox has its own supply.
Thanx a lot, uli
Urspr
I would like to thank you all for your supportbin the brownout question.
Though I had a hard time on the weekend trying to solve the problem I think
it is done now, but I donot really feel I solved it. Maybe it was just one
bad stamp, I am almost sure I double-changed it in the first palce so that I
thought it was new but it wasn't. The new one hasn't had the same problems
yet and I pray it will stay like this because the promotion tour is going on
for five more weekends...
Thanks again for your kind help,
Uli
Urspr