External drivers are reversing and going forward randomly
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So, I've built a little PCB that drives 2 more extruders on the e2 and e3 pins on the expansion connector.
I'm using 2 pololu DRV8825 drivers with all MS pins held high doing x32 microstepping
But, one of the extruders will randomly go backwards or forwards.
What the heck?
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@stoop it is probably losing steps. DRV drivers are know for the problems with holding position even when the current is set right.
Try to increase it. -
DRV8825 drivers are known for needing very slow step pulse timings. Use the T parameter of the M569 command to extend the timings. Note, this also reduces the maximum possible step rate.
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Thanks David.
What would you suggest as a figure?
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The datasheet for the DRV8825 will tell you minimum step pulse length, step pulse interval, direction setup time and direction hold time. AFAIR they are about 2.5us.
