Why does BasicX24 keep resetting?

Started by nathanchronister January 28, 2005

I've got this problem with my BX24: Certain hardware events cause the
processor to reset or restart, almost as if the power had been
briefly interrupted. I'd like your advice on possible causes and
solutions. Here's when it happens:

1. The BX24 is on a custom PCB with a ground plane (supposedly to
reduce interference). When I touch a multitester probe to the ground
plane, the processor restarts.

2. The PCB has some MOSFETs on it, which control two electric motors
with noise filtering capacitors on them. The motors are controlled
using the dual PWM outputs on the BX24. When the motors come on more
than the very slightest amount, the processor resets.

(I'm using a 7.4 volt battery to drive the motors. There is an
external 5 volt regulator which powers a PAK coprocessor and RC
receiver, and the BX uses its internal power supply. There are 1 K
resistors on the PWM outputs and 100 K pull down resistors between
the gate and ground.)

Whatever's going on here, is it possible I could fix it by putting a
capacitor somewhere, to smooth out any power fluctuations caused by
the above two events? What value/type should I use? Or would
something else be a better solution?




Did you intend to say that the BX uses it's internal voltage regulator?

If the BX is attached to the battery, which it sounds like it is, you should use a separate power supply to the BX. The grounds need to be tied together for the BX to properly control the external circuitry.

Thad

nathanchronister <> wrote:

...(I'm using a 7.4 volt battery to drive the motors...

...the BX uses its internal power supply.... ---------------------------------



Hi Thad,

Sorry I was unclear. I actually did mean that the BX is using its
internal regulator, not power supply. Do you feel that I should power
the BX from the same external regulator that the Receiver and PAK are
using? It's easy enough to give that a try.

Nathan

--- In , Thad Larson <highwayman_33402@y...>
wrote:
> Did you intend to say that the BX uses it's internal voltage
regulator?
>
> If the BX is attached to the battery, which it sounds like it is,
you should use a separate power supply to the BX. The grounds need
to be tied together for the BX to properly control the external
circuitry.
>
> Thad
>
> nathanchronister <nathanchronister@y...> wrote:
>
> ...(I'm using a 7.4 volt battery to drive the motors...
>
> ...the BX uses its internal power supply.... > ---------------------------------
>




Re: Why does BasicX24 keep resetting?
Re: Why does BasicX24 keep resetting?
Re: Why does BasicX24 keep resetting?
Actually, I was recommending that you have two on-board batteries. One for the BX and use your 7.2V for Receiver and PAK. The problem is that it doesn't take much to reset the BX24. When you pull current from you battery, the voltage may drop too low to maintain the BX and it resets.

If, for instance, you put a 9V battery to pin 24 and that battery isn't supplying power to anything else, the resetting should not occur.
Note that ALL your grounds need to be attached at some point. i.e. pin 4, pin 23, (-) of BX battery, and (-) of 7.2V battery... For proper electrical circuits, you need some form of loop.

Thad

nathanchronister <> wrote:

Hi Thad,

Sorry I was unclear. I actually did mean that the BX is using its
internal regulator, not power supply. Do you feel that I should power
the BX from the same external regulator that the Receiver and PAK are
using? It's easy enough to give that a try.

Nathan

--- In , Thad Larson <highwayman_33402@y...>
wrote:
> Did you intend to say that the BX uses it's internal voltage
regulator?
>
> If the BX is attached to the battery, which it sounds like it is,
you should use a separate power supply to the BX. The grounds need
to be tied together for the BX to properly control the external
circuitry.
>
> Thad
>
> nathanchronister <nathanchronister@y...> wrote:
>
> ...(I'm using a 7.4 volt battery to drive the motors...
>
> ...the BX uses its internal power supply.... > ---------------------------------
>


---------------------------------
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---------------------------------



Re: Why does BasicX24 keep resetting?
Re: Why does BasicX24 keep resetting?
My 2 cents worth,

The power source to drive "computer and logic(other chips)" and the power that drives any kind of "electrical mechanical devices (motor)" should be "sufficently" isolated from each other by voltage regulators and filters. Or like Thad said separate. There are trade offs. Basically you don't want "dirty"(varing voltage or noise) power going to the BX or logic.

Mark

Thad Larson <> wrote:

Actually, I was recommending that you have two on-board batteries. One for the BX and use your 7.2V for Receiver and PAK. The problem is that it doesn't take much to reset the BX24. When you pull current from you battery, the voltage may drop too low to maintain the BX and it resets.

If, for instance, you put a 9V battery to pin 24 and that battery isn't supplying power to anything else, the resetting should not occur.
Note that ALL your grounds need to be attached at some point. i.e. pin 4, pin 23, (-) of BX battery, and (-) of 7.2V battery... For proper electrical circuits, you need some form of loop.

Thad

nathanchronister wrote:

Hi Thad,

Sorry I was unclear. I actually did mean that the BX is using its
internal regulator, not power supply. Do you feel that I should power
the BX from the same external regulator that the Receiver and PAK are
using? It's easy enough to give that a try.

Nathan

--- In , Thad Larson
wrote:
> Did you intend to say that the BX uses it's internal voltage
regulator?
>
> If the BX is attached to the battery, which it sounds like it is,
you should use a separate power supply to the BX. The grounds need
to be tied together for the BX to properly control the external
circuitry.
>
> Thad
>
> nathanchronister wrote:
>
> ...(I'm using a 7.4 volt battery to drive the motors...
>
> ...the BX uses its internal power supply.... > ---------------------------------
>


---------------------------------
Yahoo! Groups Links

To
--------------------------------- Yahoo! Groups Links
---------------------------------



Re: Why does BasicX24 keep resetting?

Hi Mark and Thad,

Thanks for your suggestions earlier. Because I need to keep the
weight of my system as low as possible, I don't want to add another
battery. (I'd have to use button cells. They are expensive and would
only last a few minutes... etc.) Can you give me some more specifics
as to what kind of filtering I would need? (I don't know anything
about this so if you could recommend specific components I could try,
I'd really appreciate that.)

Thanks,
Nathan
--- In , Mark Newell <m_l_newell@y...> wrote:
> My 2 cents worth,
>
> The power source to drive "computer and logic(other chips)" and the
power that drives any kind of "electrical mechanical devices (motor)"
should be "sufficently" isolated from each other by voltage
regulators and filters. Or like Thad said separate. There are trade
offs. Basically you don't want "dirty"(varing voltage or noise) power
going to the BX or logic.
>
> Mark
>
> Thad Larson <highwayman_33402@y...> wrote:
>
> Actually, I was recommending that you have two on-board batteries.
One for the BX and use your 7.2V for Receiver and PAK. The problem is
that it doesn't take much to reset the BX24. When you pull current
from you battery, the voltage may drop too low to maintain the BX and
it resets.
>
> If, for instance, you put a 9V battery to pin 24 and that battery
isn't supplying power to anything else, the resetting should not
occur.
> Note that ALL your grounds need to be attached at some point. i.e.
pin 4, pin 23, (-) of BX battery, and (-) of 7.2V battery... For
proper electrical circuits, you need some form of loop.
>
> Thad
>
> nathanchronister wrote:
>
> Hi Thad,
>
> Sorry I was unclear. I actually did mean that the BX is using its
> internal regulator, not power supply. Do you feel that I should
power
> the BX from the same external regulator that the Receiver and PAK
are
> using? It's easy enough to give that a try.
>
> Nathan >
>
> --- In , Thad Larson
> wrote:
> > Did you intend to say that the BX uses it's internal voltage
> regulator?
> >
> > If the BX is attached to the battery, which it sounds like it is,
> you should use a separate power supply to the BX. The grounds need
> to be tied together for the BX to properly control the external
> circuitry.
> >
> > Thad
> >
> > nathanchronister wrote:
> >
> > ...(I'm using a 7.4 volt battery to drive the motors...
> >
> > ...the BX uses its internal power supply....
> >
> >
> > ---------------------------------
> > ---------------------------------
> Yahoo! Groups Links
>
> To >
> --------------------------------- > Yahoo! Groups Links >
> ---------------------------------
>



If you look at the new Board Of Education board for the Basic Stamp they have added a separate voltage regulator for the Servo Motor and 1000mF of capacitance on the incoming power to help prevent this problem. This may be your problem also.

Art

> -----Original Message-----
> From: nathanchronister [SMTP:]
> Sent: Friday, January 28, 2005 2:13 PM
> To:
> Subject: [BasicX] Why does BasicX24 keep resetting? >
> I've got this problem with my BX24: Certain hardware events cause the
> processor to reset or restart, almost as if the power had been
> briefly interrupted. I'd like your advice on possible causes and
> solutions. Here's when it happens:
>
> 1. The BX24 is on a custom PCB with a ground plane (supposedly to
> reduce interference). When I touch a multitester probe to the ground
> plane, the processor restarts.
>
> 2. The PCB has some MOSFETs on it, which control two electric motors
> with noise filtering capacitors on them. The motors are controlled
> using the dual PWM outputs on the BX24. When the motors come on more
> than the very slightest amount, the processor resets.
>
> (I'm using a 7.4 volt battery to drive the motors. There is an
> external 5 volt regulator which powers a PAK coprocessor and RC
> receiver, and the BX uses its internal power supply. There are 1 K
> resistors on the PWM outputs and 100 K pull down resistors between
> the gate and ground.)
>
> Whatever's going on here, is it possible I could fix it by putting a
> capacitor somewhere, to smooth out any power fluctuations caused by
> the above two events? What value/type should I use? Or would
> something else be a better solution? >
> Yahoo! Groups Links