Bipolar stepper motor driving by Micro-controller Xmega
I'd call these signals A1-A2-B1-B2 (as in the datasheets).

For the pattern: 
 0101->1001->1010->0110->0101... the motor will rotate one direction and for
 0101->0110->1010->1001->0101... it will go the other way.

If you add a delay between steps it will just rotate slower.