Question about drv8825 and heatsink

I think the datasheet writers are allowed to assume that the user of a microstepping stepper driver chip knows
the basic principles of operation of stepper motors and microstepping.

MarkT:
I think the datasheet writers are allowed to assume that the user of a microstepping stepper driver chip knows
the basic principles of operation of stepper motors and microstepping.

I have no argument with that.

However the writers of technical documents rarely take the trouble to dispel any confusion that might exist in the reader's mind where a few words of that nature can often lead to the "light bulb" moment.

And does this mean you are in agreement with what I wrote in Reply #19 ? I would like to have a form of words which IMHO is meaningful for a newbie and with which you (and other experts) can also agree. Newbies should not be expected to be as knowledgeable as the target audience you have described for the technical datasheets.

...R

I’d agree with the proviso that these drives will shut down if pushed. So at 2.1 amps you may start skipping steps, well more than the DVR8825 usually does.

I tried driving an '80s unipolar as bipolar with the Pololu type drivers with no success. At best they would drive for a while then shut down when the coils in the stepper warmed. I eventually used a 4 amp rated L298P with a big heat sink to drive it. The stepper was rated at 12V, 148Ω/coil times four coils. Wired as bipolar I measured 300Ω/ coil.