Help on stepper motor control

Started by fhgrossi July 13, 2006
Hi, everybody!

Ive tried to control a stepper motor (got in a broken floppy disk)
using my HC12EVM.

As I dont have any datasheet about my stepper motor, I think it is
bipolar with 4 poles operating at 5Vdc.

I programmed my software and it seems very well. I designed a bridge
push-pull circuit (so, in a bridge circuit, I have phases A, B, C and
D to bias my two windings), interfacing with HC12 board, to power my
current flow across my motor. It looks to work very well, but...

...But when I load my circuit with the stepper motors windings,
phases A and C (and B and D), whose should be completely out of phase
each other, become completely in phase, like a short circuit, and the
motor doesnt run.

Have I made a mistake? Any suggestion or issue about how to drive a
floppy disk stepper motor usind HC12?

Thank you and best regards,
Fabio