On Sunday 30 September 2001 11:03, Bernd Walter wrote:
> Controlling steppers via lpt is what I explained and showed last
> tuesday on the cosmo-project meeting.
> We used nanosleep() which worked fine for the demonstration and
> playing.
> As long as you don't have troubles with longer than requested periods
> this would fit your needs.
Is there a record of your explanation somewhere? As for the
longer-than-requested timing periods, yes that is a problem. If maximum
velocity of the drill is 30cm/s, a sudden stop would not be good. I can of
course change the MAX_V, but I'm still hoping for a non-kludgy solution.
> Nevertheless in my opinion it's a job for a dedicated CPU/controller.
> Think about using an 68HC11 or something like that.
> If you can enshure not only minimum but also maximum step times you
> can even get the motor faster - well not with lowered drill of course.
I agree. This does need a dedicated MCU. However, I only had 1 PCB layer
to work with, so simplicity was key here.
> You can shorten the steps while the motor is rotating which you can't
> do at once.
What do you mean here? I already do use variable timing for the steps BTW.
Remember, the motors perform constant-acceleration operations...it means they
slowly approach MAX_V. It's pretty neat to listen to. :)
--Bart
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