What special requirements are required when interfacing PIC microcontroller with DC motor?

Answer 1

You generally need a transistor circuit (either bi-polar or power MOSFET) the translates the command logic signals from the microcontroller to current through the windings of the motor.

Bridge and H-bridge circuits are most common. Here is an example:
http://www.bobblick.com/techref/projects/sv2hb/sv2hb.html

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