DRV8703-Q1EVM: bits in control register of DRV8703-Q1EVM for duty cycle varying purpose

Part Number: DRV8703-Q1EVM

hi,

1.how to vary the duty cycle of   DRV8703-Q1EVM  fro SPI interfacing using time.

2.which bits has to be change in the control register, config register for PWM changing or duty cycle change purpose while SPI interface using time.