Assume a constant frequency PWM. Assume that a period begins on the low to high transition. Suppose an application needs to change the duty cycle. Question 1. Should (must) changes to the duty cycle be done on the same edge (i.e. low to high)? Can the change be done on _any_ part of the cycle? Question 2. Are there scenarios where the duty cycle should be changed gradually? For example, consecutive cycles could see only one bit change until the new duty cycle is reached.