L9942 - Motor lose some microsteps

Posted on August 08, 2013 at 20:17

I want to control a stepper motor (

) with L9942 from ST.

But i have some problem because the motor dont rotate uniformly (lose some step):

My current profiles are (for DC = 111 - 1300mA):

Can you help me? Why lose some step?!

#l9942-stmdiscovery-stm32f4

This topic has been closed for replies.

ST Employee

Posted on February 02, 2014 at 19:41

The STEP signal is an input signal and it should be generated by a microcontroller or by an external circuitry.

Checking the scope-snapshot, the duty cycle of the STEP signal is not constant. this behaviour can be the source of the problem you claimed.

Visitor II

Posted on July 09, 2014 at 21:22

Good morning,

I would like to know how you manage to use the SPI protocol with the L9942 driver. I doesn't manage to use it so far...

Thank you in advance,

Thomas.

ST Employee

Posted on July 14, 2014 at 18:19

dear Thomas,

The info you need are reported in the datasheet

Please check chapter 5 and 6. Figure 10 and figure 11 are showing the timing diagrams.

Best regards,

Marco.

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