ZHCSH31B August 2017 – February 2018 DRV10987
If SpdCtrlMd = 1, the SPEED input pin is configured to operate as a PWM-encoded digital input. The PWM duty cycle applied to the SPEED pin can be varied from 0 to 100%. The speed command is proportional to the PWM input duty cycle. The speed command stops the motor when the PWM input keeps at 0 for tEN_SL_SB (see Figure 29).
The frequency of the PWM input signal applied to the SPEED pin is defined as fPWM. This is the frequency the device can accept to control motor speed. It does not correspond to the PWM output frequency that is applied to the motor phase. The PWM output frequency can be configured to be either 25 kHz when the PWMFreq bit is set to 0 or to 50 kHz when PWMFreq bit is set to 1.