ItWillDo

Goodday everyone, As a school project, I'm making a little automobile with a normal DC-Motor to go forward, and we have a single steering wheel (driven by a bipolar stepper motor) in the back to make the little car turn. Now the point of the project is that when the front sensor (an ultrasonic sensor) encounters an obstacle, the car turns to the left (We might expand later on and make him turn right, though it seemed quite useless to implement this function). The main problem I'm encountering is the fact that I have very little experience considering (stepper)motors. I have acquired a L297/L298 combo which will have to be the main control/drive-unit for the stepper motor, and the CLK sent into the L297 will be a generated PWM that starts once my controller (a PIC 16F690) gets a signal from the sensor. I'm currently ready to start building up the driver-circuit, but I still have a few questions of which I was hoping you would be able to answer. Here they are: - In the datasheet the L297 is connected straight to the L298, and this one goes into an L6210 before it goes to the motor windings. Is the L6210 really necessary or is it more of a precaution? - Pin 16 of the L297 stands for OSC and needs to have a certain chopper rate. What exactly is the function of this? And what link does it exactly have with Vref? - If I'm using only 1 L297 do I still need to connect the SYNC to something (f.e. Vs or GND) or can I leave it open? (Pin 1) - How do I calculate RS1 & RS2 which are connected to SENS1 & SENS2? Thanks in advance!