L9942 - Motor lose some microsteps

[jdiogo10]

Posted on August 08, 2013 at 20:17

I want to control a stepper motor (

http://pt.farnell.com/astrosyn/163/stepper-motor-1-8deg-5v/dp/9598650

) 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

[Brugus]

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.

[thomas239955]

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.

[Brugus]

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.