Before you do that, read this: http://www.8052.com/forum/read.phtml?id=70016


You cannot connect a motor direct to an 8051 port pin, an 8255 port pin, nor even an FPGA/CPLD port pin (unless its a very special high-power FPGA/CPLD designed specifically for the task)

You will need some power interface circuitry between the logic (8051, 8255, whatever) and the motor; eg, as Steve said, a couple of relays would do it.
(not that you'd connect relays direct to an 8051, either)


Like I said - it depends on how you arrange the power driver circuits.

Think about it - you have three states:
1. Going Forwards;
2. Going Backwards;
3. Stopped.

So yes, you need two bits; but you have one "don't care" condition - can you see why?