Computer control the speed of stepped motor

Could you describe your project a little more?

Do you have a normal stepper motor, and you want to build a driver for it and control it from an IBM compatible PC?

Do you have a stepper motor and a driver and you want to control it from a PC?

If you want to control it from a PC, what operating system are you using?

Do you want to control it from a microcontroller? If so, which one would you like to use?

How critical is the 1.28 PPS timing?

Is is a Unipolar or a Bipolar stepper motor. Any details or specs on the motor and what driver and controller board your using?

This is a 4-phase stepper motor. I don't have more specs about it.

I want to build a drive program, and control it from Windows 2000 or higher.

I don't have microcontroller for it. My task is to write a program that can control the speed of the motor.

The 1.28PPS timing is only information that is related to the speed from the manual.

Please give a help. Thank you so much

Thank you.

I will put more description about my project below:

Computer will generate pulses on Pin 4 of DB9 serial port. The input pulse, a square wave or a spike is needed to trigger the stepper motor driver circuit. The square wave starts at 10pps up to 500pps at 50% cycle. The voltage of the pulse can be between 5 vdc and 18 vdc.

Pin 4 : pulse input; Pin 5: ground; Pin 7: direction

It may be my question how to generate the square wave that can control the speed of the stepper motor.

I look forword to hearing from you, our expert. Thank you so much

Well, why not *add* a microcontroller? Sure seems to make more sense than using a Win2K/XP serial port to drive it directly -- especially since "DOS-like" serial port access isn't avaialble in 2K/XP.

Ok, I think you have a stepper motor and a stepper-motor driver, and you swant to use a PC running Windows 2000 to create pulses out the RS232 port to drive the stepper-motor driver.

If that's correct, I can't help you.