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Stepper impulse width mod SOS

Added by minczer over 5 years ago

Hi,

please help me!
I have a problem with the pulse width of stepping. I measured cca.2us, but the external controller like 5us.
Where can I mod in the source code?

Thanks


Replies (2)

RE: Stepper impulse width mod SOS - Added by jaap over 5 years ago

Hi,

The pulse is created in stepper.cpp, part of the grbl code. There are relevant two routines:

set_step_pins(); // line 309
clear_all_step_pins(); // line 466

The time between the calling of those two in st_interrupt() determines the pulse width.

The comment on line 406 reads: clear the pins, assume that we spend enough CPU cycles in the previous statements for the steppers to react (>1usec)
. So much for "pulse timing" :-(

I suppose you could solve it by adding

wait_us(3)

just before line 406 (although adding a wait statement in interrupts is generally considered a Bad Thing)

RE: Stepper impulse width mod SOS - Added by minczer over 5 years ago

hi,

It's really a bad thing, but working!
Thanks!
1us wait enough for the stepper driver!

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