# Thread: Convert Step/direction to phase drive

1. ## Convert Step/direction to phase drive

Does anyone know how I can convert a step/direction signal to phase drive?
Mach 2 uses step/direction and I want to control a BP boss which uses phase drive. Quadrature I think its called, it looks like this:
L L
H L
H H
L H

Their is bound to be a way to do this with transistors or something. I don't completely understand what step\direction looks like, nor do I understand how 4 steps (defined above) can control a stepper when their are many more than 4 steps per revolution.

2. There is only four basic methods for drive command, step and direction, +- analogue, digital and Two phase sinusoidal. It looks like the latter maybe the one you are looking for?
Al.

3. I think I know what I am trying to do now, I just don't know how to do it. The pc output signal would look like this:
Direction: 1 (cw) or 0(ccw)
Step: pulses on and off for each step

Every time the step signal pulses I need to somehow shift my output from 0 to 1 or from 1 to zero, ultimately looking like above
00 Step 1
10 Step 2
11 Step 3
01 Step 4

a low direction signal will reverse steps from 4 to 1
Question is what electrical gadget will take a momentary input and convert its output from high to low (or low to high) for each input pulse.
I should have paid more attention in circuits class!

4. Hi,

A basic circuit to this is uses 2 flipflops (74hc74) and 2 exclusive OR gates (74hc86).
See pic.

John

• Thanks John!
Do you know of any online references for this kind of stuff? Something that tells you what specific components do, like what a flip flop does?

• Hmm, I think this circuit comes from a internet tutorial : "jones on stepper motors" or something like that.. Just do a google search. I believe there was also a PCB layout in this tutorial.

John

• How is that any different from Direction / Step??

• I stopped by the local radio shack to see if I could find a flipflop, no luck, but I did find a counter it is 8-bit though. It seems that if I had a 2-bit binary counter it would be a piece of cake. Problem is I can't find anyone that makes them! The lowest I can find is 4-bit. So now i'm thinking can I convert 8 bit to two bit?
What would be nice is a program (kinda like CAD for electronics) for designing circuits and testing them. Someone is bound to know of one?

• Could somebody please explain the application for this?

I cannot understand the bigger context of the problem.

I thought computer speaks to driver which drives stepper which controls router. Is this somewhere within the driver stage and is therefore a non issue for anyone taking the gecko path?

Thanks

Andy

• Use a CD4013 for the dual D-Flop and a CD4030 for the quad XOR gate. Tie all unused inputs to ground. See www.digikey.com or other for these parts.

Mariss

• andy, the original drive system is already intact and I don't want to spend the big bucks to replace it just yet. The old Bridgeport computer is not up to par so I want to replace it with a pc running mach2. I can use the original drive system if I can output the phase signal. It would be a piece of cake if the program would output the proper signal.

• ## warning: error in first diagram

Guys,

I just noticed I had swapped the Q en Q_not outputs in the diagram... I redrew this from a PDF file. I now have replaced the schematic diagram in my initial post to be sure there is no false version on the site. Sorry about that. Now I've double-double checked it.

jderou,

A 2 bit counter can't be used directly. It produces

00
01
10
11

wheras you need

00
10
11
01

You could use some logic to convert one in the other but its probably easyer to try if you can get the components Mariss suggested. they should work fine.

John

• Page 1 of 2 12 Last