Well, the circuit should like this:
...........x-----||---x
...........|.............|
|O|-----x---|<|----x---- |X| this is the input of L298
Don't care bout the .... , I have to add .... because if I don't, it cannot view exactly. ---- is the wire, and x is connected. |X| is the input pin of L298 and |O| is the output of your MC. You need only 1 pin, but in stead of connect it directly, you connect like this. And from the input of L298 to output of L298, you add a 10K resistor.
If you got a email, I'll send you the test circuit, I used to test L298 with its all characters, such as: short circuit, feedback voltage via sense pins, 4A driver, ... and especially, we should note that if we use the normal diode for the H brigde, we cannot drive the motor upto 5KHz period of PWM, but if we use fast diode, it works good. And PWM is usually used at that frequency.