I/O pins and maximal current
Archiver
Posts: 46,084
Hello!
I maybe have damaged my BSII :-(
I forgot the resistor when I put a LED on one of the i/o-pins of my
BSII. I realized this and put the resistor in (unfortunately after
running a program putting the LEDs i/o-pins high). Now, when I use the
LED, or other devices on i/o-pins, the voltage drops to 4,5V for just
a tiny little moment in a regular frequency (maybe 1 time per second).
Is this a resonable permanent damage to the BSII after what I have
done? Do I have to replace it completely, or is there any way to fix
it?
Regards David
--- In basicstamps@egroups.com, "Steve Tatum" <swt@p...> wrote:
> Mike,
> the bs2 I/O pins can 20mA and sink 25mA each. You will have to use
NPN
> transistor switching if you require the use of a lot of output pins.
Use
> the Vdd to source your servo(s) but you may want to make sure that
your amp
> draw is in the exceptable range for the output of the Voltage
Regulator that
> you are using.
>
>
Original Message
> From: Flaming Headphones [noparse][[/noparse]mailto:headphones99@i...]
> Sent: Thursday, August 03, 2000 8:58 PM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] BOE bot I/O pins and current
>
>
> Hi guys,
> I recently got a boe bot, and now that I've zipped right through the
> experiments, I've got lots of ideas to try out. First question: I've
heard
> that if there's too much current draw/sink/something like that, the
I/O
> pins (and therefore the stamp) can be damaged. Is this true? If so,
how do
> you prevent this?
>
> Second question: What is current sink and draw? I'm confused. :-)
>
> Lastly: I know that servos such as the ones in the boe bot are
designed to
> run off of 4-6 volts (at least that's what my r/c airplanes battery
packs
> feed them.) Is if OK to run them off the 9 volts that come from the
VIN or
> should I hook it up to the VDD (regulated to 5 volts) on the boe?
The
> reason I ask is because on the boe you have a choice between
connecting a 9
> volt battery or 4 AA cells, and I've got a lot of 9 volt batterys
and very
> few AAs.
>
> Thanks for putting up with my newbie questions!
> Mike Ball, AKA Flaming Headphones
I maybe have damaged my BSII :-(
I forgot the resistor when I put a LED on one of the i/o-pins of my
BSII. I realized this and put the resistor in (unfortunately after
running a program putting the LEDs i/o-pins high). Now, when I use the
LED, or other devices on i/o-pins, the voltage drops to 4,5V for just
a tiny little moment in a regular frequency (maybe 1 time per second).
Is this a resonable permanent damage to the BSII after what I have
done? Do I have to replace it completely, or is there any way to fix
it?
Regards David
--- In basicstamps@egroups.com, "Steve Tatum" <swt@p...> wrote:
> Mike,
> the bs2 I/O pins can 20mA and sink 25mA each. You will have to use
NPN
> transistor switching if you require the use of a lot of output pins.
Use
> the Vdd to source your servo(s) but you may want to make sure that
your amp
> draw is in the exceptable range for the output of the Voltage
Regulator that
> you are using.
>
>
Original Message
> From: Flaming Headphones [noparse][[/noparse]mailto:headphones99@i...]
> Sent: Thursday, August 03, 2000 8:58 PM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] BOE bot I/O pins and current
>
>
> Hi guys,
> I recently got a boe bot, and now that I've zipped right through the
> experiments, I've got lots of ideas to try out. First question: I've
heard
> that if there's too much current draw/sink/something like that, the
I/O
> pins (and therefore the stamp) can be damaged. Is this true? If so,
how do
> you prevent this?
>
> Second question: What is current sink and draw? I'm confused. :-)
>
> Lastly: I know that servos such as the ones in the boe bot are
designed to
> run off of 4-6 volts (at least that's what my r/c airplanes battery
packs
> feed them.) Is if OK to run them off the 9 volts that come from the
VIN or
> should I hook it up to the VDD (regulated to 5 volts) on the boe?
The
> reason I ask is because on the boe you have a choice between
connecting a 9
> volt battery or 4 AA cells, and I've got a lot of 9 volt batterys
and very
> few AAs.
>
> Thanks for putting up with my newbie questions!
> Mike Ball, AKA Flaming Headphones
Comments
>I forgot the resistor when I put a LED on one of the i/o-pins of my
>BSII. I realized this and put the resistor in (unfortunately after
>running a program putting the LEDs i/o-pins high). Now, when I use the
>LED, or other devices on i/o-pins, the voltage drops to 4,5V for just
>a tiny little moment in a regular frequency (maybe 1 time per second).
>Is this a resonable permanent damage to the BSII after what I have
>done? Do I have to replace it completely, or is there any way to fix
>it?
When a program ends, the BASIC Stamp goes into a low-power sleep mode that
might explain what you are seeing. E.g.,
led con 0
high led
If that is the complete program, P0 will be an output most of the time, but
periodically (about 2 second intervals) it will turn into an input for a
brief time (about 18 milliseconds) and the led will flicker. There are
ways to work around that in either the software (using a loop or the stop
command), or in hardware (using a buffer). The good news is, I don't think
you damaged the Stamp.