Drive the hard disk motor with DRV11873,It is found that when the motor starts, the direction of rotation is random。If the motor starts in the right direction of rotation, it can work properly.
If the motor starts not in the right direction of rotation, it will run at low speeds in the wrong direction with 70% duty cycle test。
With 10% duty cycle test, the motor stops and goes, and eventually moves in the right direction.
No matter what the duty cycle is, if we set a right direction for it by hand, it will run properly.