PIC16F84A unipolar stepper driver frequency

[same79]

I want to use PIC16f84a with power mosfet to driver unipolar driver. Please tell me about its frequency rate performance. I think it can provide me 1000 steps per second [means higher frequency]. Or how to make it to provide higher frequency? Or how about to use PIC16F877A instead of PIC16f84a to get higher frequency?

[RomanLini]

Both those chips will give about the same frequency.

And both should be good for 50000 steps per second (or more!) if you run them with a 20Mhz xtal.

[same79]

Thanks for your reply. There is attached driver that about I am talking. There is also an 20Mhz xtal included. Now I would like to talk some bit about it. It also support half/full step mode. There is only one jumper called JP1. Is it change the stepping mode of all motors? But want to change stepping mode of any axis motor at any time individually. Is this circuit has such facility to change stepping mode individually?

What dose JP2 [spare] here?

What is "Spindle Relay" between J6-1 and J6-2? why is it?

Is it possible to use bigger mosfet to handle more amp [if needed in future]?

What is a small separate schematic at right upper corner? and what is IC1P and IC3P written in this circuit?

Thanks in advance

[george4657]

This is a simple controller and only option would be full step or half step and all motors would be the same.

JP2 goes to the reset pin on PIC so shorting it would reset the stepper.

The "Spindle Relay" is to control the spindle speed using the PC. This is an advanced feature that is not easy to add to router motor.

This type of controller has no current limiting so current limiting resistors have to be added externally. These will be large and expensive for high current. 4 X 3 = 12 required.These may be the most expensive part of the build. Also since so much power is lost in heat a bigger power supply is require than a chopper type circuit would require.

The IC1P and IC3P are pins on the 74HC14 for power and ground?

An interesting circuit but I would only use for lower power circuits of 2 to 3 Amps.

George