negitive current on an arduino

Hi,
another newbie question;
How do you make a digital pin on an arduino negative.
Thank you,
Jaredpi

Drive it negative from an external source.

Course, anything below -0.5V will blow the pin:

Voltage on any Pin except RESET
with respect to Ground ................................-0.5V to VCC+0.5V

How do you make a digital pin on an arduino negative.

Are you talking about inputs or outputs?
Why do you want to do this?
There is no need / you can't do it.

If you are just talking current:
An output pin can Source (supply) 5v and up to 40mA to a load needs 5V or less.
Example, output pin to anode to LED, cathode to current limit resistor, to ground. LEDs generally have a max of 20mA.

An output pin can Sink up to 40mA from a load that is driven from 5V.
Example, output pin to current limit resistor to cathode of LED, Anode to 5V.

Sourcing current to a load is typically indcated as negative current on data sheets.

How do you make a digital pin on an arduino negative.

You real should define what you mean by negative.

Lefty

That wouldn't leave us anything to speculate about then :grin:

I don't think he knows. :wink:

define what you mean by negative.

Why do you want to do this?

To clarify, I am building an arduino-powered robot and need help getting the motors to go both ways on a digital pin.
Sorry for any confusion.
Thank you,
Jaredpi

Can't do that. You need switching to swap the motor poles back & forth so current flows + to - for one direction, and - to + to spin the other direction.
Need either relays that you control in pairs (assuming you will need an off-state as well), or an H-Bridge chip, see L293 as an example.
Pins are only good for 30-35 mA, and will burn out when motor stalls (and acts like a short circuit).