DRV8711 Stall Detection

Hi, 

We use DRV8711 to drive a NEMA23 stepper motor, the internal stall detection is employed to avoid hard collision, all of parameters are adjusted to suitable value and the function is okay, however, sometimes ago we made a small mass production and found that it did not work, no matter how I adjust the registers, the stall detection always fail. neither the software nor PCB layout is changed, we cannot find out the root cause, Is it probably caused by chip production lot?

The internal stall detection parameters:

SMPLTH=1, SDCNT=1, VDIV=2, SDTHR=100, MICROSTEP=8, VELOCITY=128000pps

Thanks and Regards.

Liur