powering my stamp
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Posts: 46,084
I'm designing a new circuit for a BS2 that will run on a 9v battery.
Can I just connect the 9v directly to the VIN pin on the stamp, or
should I use a separate 5v regulator and connect it to VDD?
Can I just connect the 9v directly to the VIN pin on the stamp, or
should I use a separate 5v regulator and connect it to VDD?
Comments
andywatson@m... writes:
> I'm designing a new circuit for a BS2 that will run on a 9v battery.
> Can I just connect the 9v directly to the VIN pin on the stamp, or
> should I use a separate 5v regulator and connect it to VDD?
>
>
It is safer to use an external regulator. The Stamp on-board regulator has a
low current capacity, 50ma, I think.
Sid Weaver
W4EKQ
Port Richey, FL
[noparse][[/noparse]Non-text portions of this message have been removed]
really isn't much of an issue.
--- In basicstamps@yahoogroups.com, Newzed@a... wrote:
> In a message dated 3/4/2004 2:24:47 PM Eastern Standard Time,
> andywatson@m... writes:
>
>
> > I'm designing a new circuit for a BS2 that will run on a 9v
battery.
> > Can I just connect the 9v directly to the VIN pin on the stamp,
or
> > should I use a separate 5v regulator and connect it to VDD?
> >
> >
>
> It is safer to use an external regulator. The Stamp on-board
regulator has a
> low current capacity, 50ma, I think.
>
>
> Sid Weaver
> W4EKQ
> Port Richey, FL
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
a very low dropout on-chip regulator. In practice,
I have never done this, though it is in the group
of labs I'd like to do -- put a 9-volt on a BS2 and
see how long it will run before the 9-volt reaches
6 volts.
And you do want to be very careful driving anything
else with the BS2's VDD pin as an output. It sounds
like you ARE being careful -- so this should be cool.
Note the BS2's '16' serial port is powered by the
PC talking to it, so you shouldn't have to worry
about that taking current.
--- In basicstamps@yahoogroups.com, "andy_watson5" <andywatson@m...>
wrote:
> I'm designing a new circuit for a BS2 that will run on a 9v
battery.
> Can I just connect the 9v directly to the VIN pin on the stamp, or
> should I use a separate 5v regulator and connect it to VDD?
wrote:
> I'm designing a new circuit for a BS2 that will run on a 9v
battery.
> Can I just connect the 9v directly to the VIN pin on the stamp, or
> should I use a separate 5v regulator and connect it to VDD?
The on board regulator is sized correctly to run the Stamp and the
max safe I/O current.
That said, if you need any additional current, you may think of an
additional regulator (if the other thing cannot be run off the 9V
battery directly).
Good Luck
wrote:
>
> And you do want to be very careful driving anything
> else with the BS2's VDD pin as an output. It sounds
> like you ARE being careful -- so this should be cool.
>
Can I still connect a switch between the VDD pin and one of the
stamp's input pins for an active high input?
5 volts at Vdd. For saftey, you may want to put a 220 ohm resistor
inline with your button input; that way a programming error won't cause
the death of the pin.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: andy_watson5 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-yVd6Sg_hcfdfwHlGqKLBPCg87xndYsjZQ8R1sap6Xjl1xGXQ-ViooI9quelRjMPLsUqXgZA781Q]andywatson@m...[/url
Sent: Thursday, March 04, 2004 2:13 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: powering my stamp
--- In basicstamps@yahoogroups.com, "Allan Lane" <allan.lane@h...>
wrote:
>
> And you do want to be very careful driving anything
> else with the BS2's VDD pin as an output. It sounds
> like you ARE being careful -- so this should be cool.
>
Can I still connect a switch between the VDD pin and one of the
stamp's input pins for an active high input?
wrote:
> Yes -- so long as you provide at least 6 volts to the Vin pin
you'll get
> 5 volts at Vdd. For saftey, you may want to put a 220 ohm resistor
> inline with your button input; that way a programming error won't
cause
> the death of the pin.
>
What type of programming error could cause the death of a pin?
active input, poof goes the pin -- this happens to the best of us. On a
couple of our student-based boards we've actually started incorporating
these resistors, much to the delight of teachers across the globe.
For your active-high input you can do this:
----
<Pin>
[noparse][[/noparse]220 ohm]
*
o o
Vdd
|
[noparse][[/noparse]10K]
|
Vss
With this circuit the pin current would be limited to about 23 mA if the
pin was made an output-low and the button pressed.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: andy_watson5 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=34T2fIND4tgl-qTLtuXKO6-QHMT9twvchyA7250xRcaeYhnghbVfSG90A7eqA7iBnp0ozhzSNfTtcVKYW34]andywatson@m...[/url
Sent: Thursday, March 04, 2004 2:33 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: powering my stamp
--- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
wrote:
> Yes -- so long as you provide at least 6 volts to the Vin pin
you'll get
> 5 volts at Vdd. For saftey, you may want to put a 220 ohm resistor
> inline with your button input; that way a programming error won't
cause
> the death of the pin.
>
What type of programming error could cause the death of a pin?
> --- In basicstamps@yahoogroups.com, "Jon Williams"
> <jwilliams@p...>
> wrote:
> > Yes -- so long as you provide at least 6 volts to
> the Vin pin
> you'll get
> > 5 volts at Vdd. For saftey, you may want to put a
> 220 ohm resistor
> > inline with your button input; that way a
> programming error won't
> cause
> > the death of the pin.
> What type of programming error could cause the death
> of a pin?
Accidentally setting that pin to an output... =(
=====
Chris Savage
Knight Designs
324 West Main Street
Montour Falls, NY 14865
(607) 535-6777
http://www.knightdesigns.com
__________________________________
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