Programmable ramp-up on start and/or ramp-down on stop are also possible with the PCA9629. The ramp-up (or motor speed up) starts from the maximum pulse width and the ramp-down (or motor speed down) ends at the same maximum pulse width. The maximum pulse width, accelerating rate and decelerating rate are defined in the ramp control registers and these translate to the ramp acceleration and deceleration. The top (or final) speed of the ramp control is defined in both the PRE-SCALER and STEP_PULSE_WIDTH values in step pulse width registers. During ramp-up, the step pulse width is automatically decremented (from the maximum value for step pulse width in the chosen range) until the final value is reached. Similarly, during ramp-down, the step pulse width is automatically incremented from the current value, until it reaches the maximum value for step pulse width in the chosen range.