Hijack of Evans stepper driver thread

[John Stevenson]

I don't have time to argue Paul, I'm going to town for a blood test.

Ask for nurse Dracula

[EVguru]

The L297/298 combination produces a horrible racket of squeals and squelches..

They also seem to leak smoke without much provocation and are a pretty dated design these days. They must be what, 30 years old?

[Paul Alciatore]

The L297/298 combination produces a horrible racket of squeals and squelches..like having a bag of angry cats next to you router.
The increasing current slope is always shallower than the decreasing slope.which leads to unstable waveforms and the noise.

You should research the free 5 microstep TinyCPLD coolrunner based design Mariss F. The increasing current slope is steeper than the decreasing current slope leading to a stable waveform and virtually no noise under 20khz.

I used the Mariss front end combined with dual motorola MC33887 5A 50v bridges with internal current sensing.Much better imho.
Mariss's 5 microstep tutorial and pinmo's code are available on cnczone.



Using the Marris disign ..I can get in at under $20...excluding time.

Rob

Under $20. I would love to see the design.

Do you have a link?

[MrSleepy]

Under $20. I would love to see the design.

Do you have a link?

This is a link to the design provided by Mariss F. on cnczone.
Its a complete tutorial on the coolrunner XC2c256..the ide..and a blow by blow explanation of the design..
I believe it to be in essence a 0.75 Gecko (G203?)design...it does not incorporate mid band resonance control..

The complete verilog code has been tweaked and posted on cnczone by pinmo.

http://rapidshare.com/files/370379490/5_microstep_tutorial.pdf

On my version..I have sacrificed the high voltage capability of the discrete H bridges and used MC33887 H bridges on 24v. I made a Fxxx up though..the MC33887 is only rated for 10kHz..but I'd already built the boards ..but they work fine..I hind sight I may have been better off using the Nat Semi H bridges.

Rob