RC circuits drift with temerature and voltage, not an accurate source of time or position information. A better whay uses a timer chip like the Z80 CTC or 8253. Though a PIC or other micro(8048, 8051) usually has a timer counter on board. Generally speaking using a micro as a morot controller is commmonplace. The real trick is being able to start at a calibrated point and return back to it (resetability) as well as move to any point with accuracy. So beside the mechanical problem of movement there are the issues of knowing where you are or at least where the start point is. Yes, you can if CMOS, if not then add a 330 ohm pullup resistor. The Z80 requires a clock that swings closer to ground and Vcc than all the other pins. Because most digital hackers would not know what it is maybe? A parallel or series resonant osc refers to the whay the crystal is connected in and used. The inportant thing is to meet the rise and fall times as well as the logic high and low voltages that the Z80 requires. and that wasn't addressed well there. If google isn't helpful then you asked the wrong question. There is literally mountains of z80 information out there. Allison